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a724f313f8
In the search loop of the binary search function, we are doing a division by 2 of the sum of the high and low slots. Because the slots are integers, the generated assembly code for it is the following on x86_64: 0x00000000000141f1 <+145>: mov %eax,%ebx 0x00000000000141f3 <+147>: shr $0x1f,%ebx 0x00000000000141f6 <+150>: add %eax,%ebx 0x00000000000141f8 <+152>: sar %ebx It's a few more instructions than a simple right shift, because signed integer division needs to round towards zero. However we know that slots can never be negative (btrfs_header_nritems() returns an u32), so we can instead use unsigned types for the low and high slots and therefore use unsigned integer division, which results in a single instruction on x86_64: 0x00000000000141f0 <+144>: shr %ebx So use unsigned types for the slots and therefore unsigned division. This is part of a small patchset comprised of the following two patches: btrfs: eliminate extra call when doing binary search on extent buffer btrfs: do unsigned integer division in the extent buffer binary search loop The following fs_mark test was run on a non-debug kernel (Debian's default kernel config) before and after applying the patchset: $ cat test.sh #!/bin/bash DEV=/dev/sdi MNT=/mnt/sdi MOUNT_OPTIONS="-o ssd" MKFS_OPTIONS="-O no-holes -R free-space-tree" FILES=100000 THREADS=$(nproc --all) FILE_SIZE=0 umount $DEV &> /dev/null mkfs.btrfs -f $MKFS_OPTIONS $DEV mount $MOUNT_OPTIONS $DEV $MNT OPTS="-S 0 -L 6 -n $FILES -s $FILE_SIZE -t $THREADS -k" for ((i = 1; i <= $THREADS; i++)); do OPTS="$OPTS -d $MNT/d$i" done fs_mark $OPTS umount $MNT Results before applying patchset: FSUse% Count Size Files/sec App Overhead 2 1200000 0 174472.0 11549868 4 2400000 0 253503.0 11694618 4 3600000 0 257833.1 11611508 6 4800000 0 247089.5 11665983 6 6000000 0 211296.1 12121244 10 7200000 0 187330.6 12548565 Results after applying patchset: FSUse% Count Size Files/sec App Overhead 2 1200000 0 207556.0 11393252 4 2400000 0 266751.1 11347909 4 3600000 0 274397.5 11270058 6 4800000 0 259608.4 11442250 6 6000000 0 238895.8 11635921 8 7200000 0 211942.2 11873825 Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
5037 lines
131 KiB
C
5037 lines
131 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (C) 2007,2008 Oracle. All rights reserved.
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*/
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#include <linux/sched.h>
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#include <linux/slab.h>
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#include <linux/rbtree.h>
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#include <linux/mm.h>
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#include <linux/error-injection.h>
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#include "messages.h"
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#include "ctree.h"
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#include "disk-io.h"
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#include "transaction.h"
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#include "print-tree.h"
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#include "locking.h"
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#include "volumes.h"
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#include "qgroup.h"
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#include "tree-mod-log.h"
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#include "tree-checker.h"
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#include "fs.h"
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#include "accessors.h"
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#include "extent-tree.h"
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#include "relocation.h"
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#include "file-item.h"
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static struct kmem_cache *btrfs_path_cachep;
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static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
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*root, struct btrfs_path *path, int level);
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static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root *root,
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const struct btrfs_key *ins_key, struct btrfs_path *path,
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int data_size, int extend);
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static int push_node_left(struct btrfs_trans_handle *trans,
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struct extent_buffer *dst,
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struct extent_buffer *src, int empty);
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static int balance_node_right(struct btrfs_trans_handle *trans,
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struct extent_buffer *dst_buf,
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struct extent_buffer *src_buf);
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static void del_ptr(struct btrfs_root *root, struct btrfs_path *path,
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int level, int slot);
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static const struct btrfs_csums {
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u16 size;
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const char name[10];
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const char driver[12];
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} btrfs_csums[] = {
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[BTRFS_CSUM_TYPE_CRC32] = { .size = 4, .name = "crc32c" },
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[BTRFS_CSUM_TYPE_XXHASH] = { .size = 8, .name = "xxhash64" },
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[BTRFS_CSUM_TYPE_SHA256] = { .size = 32, .name = "sha256" },
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[BTRFS_CSUM_TYPE_BLAKE2] = { .size = 32, .name = "blake2b",
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.driver = "blake2b-256" },
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};
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/*
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* The leaf data grows from end-to-front in the node. this returns the address
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* of the start of the last item, which is the stop of the leaf data stack.
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*/
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static unsigned int leaf_data_end(const struct extent_buffer *leaf)
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{
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u32 nr = btrfs_header_nritems(leaf);
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if (nr == 0)
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return BTRFS_LEAF_DATA_SIZE(leaf->fs_info);
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return btrfs_item_offset(leaf, nr - 1);
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}
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/*
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* Move data in a @leaf (using memmove, safe for overlapping ranges).
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*
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* @leaf: leaf that we're doing a memmove on
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* @dst_offset: item data offset we're moving to
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* @src_offset: item data offset were' moving from
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* @len: length of the data we're moving
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*
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* Wrapper around memmove_extent_buffer() that takes into account the header on
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* the leaf. The btrfs_item offset's start directly after the header, so we
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* have to adjust any offsets to account for the header in the leaf. This
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* handles that math to simplify the callers.
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*/
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static inline void memmove_leaf_data(const struct extent_buffer *leaf,
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unsigned long dst_offset,
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unsigned long src_offset,
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unsigned long len)
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{
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memmove_extent_buffer(leaf, btrfs_item_nr_offset(leaf, 0) + dst_offset,
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btrfs_item_nr_offset(leaf, 0) + src_offset, len);
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}
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/*
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* Copy item data from @src into @dst at the given @offset.
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*
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* @dst: destination leaf that we're copying into
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* @src: source leaf that we're copying from
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* @dst_offset: item data offset we're copying to
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* @src_offset: item data offset were' copying from
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* @len: length of the data we're copying
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*
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* Wrapper around copy_extent_buffer() that takes into account the header on
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* the leaf. The btrfs_item offset's start directly after the header, so we
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* have to adjust any offsets to account for the header in the leaf. This
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* handles that math to simplify the callers.
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*/
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static inline void copy_leaf_data(const struct extent_buffer *dst,
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const struct extent_buffer *src,
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unsigned long dst_offset,
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unsigned long src_offset, unsigned long len)
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{
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copy_extent_buffer(dst, src, btrfs_item_nr_offset(dst, 0) + dst_offset,
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btrfs_item_nr_offset(src, 0) + src_offset, len);
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}
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/*
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* Move items in a @leaf (using memmove).
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*
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* @dst: destination leaf for the items
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* @dst_item: the item nr we're copying into
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* @src_item: the item nr we're copying from
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* @nr_items: the number of items to copy
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*
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* Wrapper around memmove_extent_buffer() that does the math to get the
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* appropriate offsets into the leaf from the item numbers.
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*/
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static inline void memmove_leaf_items(const struct extent_buffer *leaf,
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int dst_item, int src_item, int nr_items)
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{
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memmove_extent_buffer(leaf, btrfs_item_nr_offset(leaf, dst_item),
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btrfs_item_nr_offset(leaf, src_item),
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nr_items * sizeof(struct btrfs_item));
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}
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/*
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* Copy items from @src into @dst at the given @offset.
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*
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* @dst: destination leaf for the items
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* @src: source leaf for the items
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* @dst_item: the item nr we're copying into
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* @src_item: the item nr we're copying from
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* @nr_items: the number of items to copy
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*
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* Wrapper around copy_extent_buffer() that does the math to get the
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* appropriate offsets into the leaf from the item numbers.
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*/
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static inline void copy_leaf_items(const struct extent_buffer *dst,
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const struct extent_buffer *src,
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int dst_item, int src_item, int nr_items)
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{
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copy_extent_buffer(dst, src, btrfs_item_nr_offset(dst, dst_item),
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btrfs_item_nr_offset(src, src_item),
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nr_items * sizeof(struct btrfs_item));
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}
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int btrfs_super_csum_size(const struct btrfs_super_block *s)
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{
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u16 t = btrfs_super_csum_type(s);
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/*
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* csum type is validated at mount time
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*/
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return btrfs_csums[t].size;
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}
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const char *btrfs_super_csum_name(u16 csum_type)
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{
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/* csum type is validated at mount time */
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return btrfs_csums[csum_type].name;
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}
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/*
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* Return driver name if defined, otherwise the name that's also a valid driver
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* name
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*/
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const char *btrfs_super_csum_driver(u16 csum_type)
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{
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/* csum type is validated at mount time */
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return btrfs_csums[csum_type].driver[0] ?
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btrfs_csums[csum_type].driver :
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btrfs_csums[csum_type].name;
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}
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size_t __attribute_const__ btrfs_get_num_csums(void)
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{
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return ARRAY_SIZE(btrfs_csums);
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}
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struct btrfs_path *btrfs_alloc_path(void)
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{
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might_sleep();
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return kmem_cache_zalloc(btrfs_path_cachep, GFP_NOFS);
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}
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/* this also releases the path */
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void btrfs_free_path(struct btrfs_path *p)
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{
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if (!p)
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return;
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btrfs_release_path(p);
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kmem_cache_free(btrfs_path_cachep, p);
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}
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/*
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* path release drops references on the extent buffers in the path
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* and it drops any locks held by this path
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*
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* It is safe to call this on paths that no locks or extent buffers held.
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*/
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noinline void btrfs_release_path(struct btrfs_path *p)
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{
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int i;
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for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
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p->slots[i] = 0;
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if (!p->nodes[i])
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continue;
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if (p->locks[i]) {
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btrfs_tree_unlock_rw(p->nodes[i], p->locks[i]);
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p->locks[i] = 0;
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}
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free_extent_buffer(p->nodes[i]);
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p->nodes[i] = NULL;
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}
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}
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/*
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* We want the transaction abort to print stack trace only for errors where the
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* cause could be a bug, eg. due to ENOSPC, and not for common errors that are
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* caused by external factors.
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*/
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bool __cold abort_should_print_stack(int errno)
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{
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switch (errno) {
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case -EIO:
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case -EROFS:
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case -ENOMEM:
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return false;
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}
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return true;
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}
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/*
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* safely gets a reference on the root node of a tree. A lock
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* is not taken, so a concurrent writer may put a different node
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* at the root of the tree. See btrfs_lock_root_node for the
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* looping required.
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*
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* The extent buffer returned by this has a reference taken, so
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* it won't disappear. It may stop being the root of the tree
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* at any time because there are no locks held.
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*/
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struct extent_buffer *btrfs_root_node(struct btrfs_root *root)
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{
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struct extent_buffer *eb;
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while (1) {
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rcu_read_lock();
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eb = rcu_dereference(root->node);
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/*
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* RCU really hurts here, we could free up the root node because
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* it was COWed but we may not get the new root node yet so do
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* the inc_not_zero dance and if it doesn't work then
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* synchronize_rcu and try again.
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*/
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if (atomic_inc_not_zero(&eb->refs)) {
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rcu_read_unlock();
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break;
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}
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rcu_read_unlock();
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synchronize_rcu();
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}
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return eb;
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}
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/*
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* Cowonly root (not-shareable trees, everything not subvolume or reloc roots),
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* just get put onto a simple dirty list. Transaction walks this list to make
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* sure they get properly updated on disk.
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*/
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static void add_root_to_dirty_list(struct btrfs_root *root)
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{
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struct btrfs_fs_info *fs_info = root->fs_info;
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if (test_bit(BTRFS_ROOT_DIRTY, &root->state) ||
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!test_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state))
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return;
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spin_lock(&fs_info->trans_lock);
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if (!test_and_set_bit(BTRFS_ROOT_DIRTY, &root->state)) {
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/* Want the extent tree to be the last on the list */
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if (root->root_key.objectid == BTRFS_EXTENT_TREE_OBJECTID)
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list_move_tail(&root->dirty_list,
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&fs_info->dirty_cowonly_roots);
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else
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list_move(&root->dirty_list,
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&fs_info->dirty_cowonly_roots);
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}
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spin_unlock(&fs_info->trans_lock);
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}
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/*
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* used by snapshot creation to make a copy of a root for a tree with
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* a given objectid. The buffer with the new root node is returned in
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* cow_ret, and this func returns zero on success or a negative error code.
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*/
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int btrfs_copy_root(struct btrfs_trans_handle *trans,
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struct btrfs_root *root,
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struct extent_buffer *buf,
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struct extent_buffer **cow_ret, u64 new_root_objectid)
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{
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struct btrfs_fs_info *fs_info = root->fs_info;
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struct extent_buffer *cow;
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int ret = 0;
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int level;
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struct btrfs_disk_key disk_key;
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WARN_ON(test_bit(BTRFS_ROOT_SHAREABLE, &root->state) &&
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trans->transid != fs_info->running_transaction->transid);
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WARN_ON(test_bit(BTRFS_ROOT_SHAREABLE, &root->state) &&
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trans->transid != root->last_trans);
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level = btrfs_header_level(buf);
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if (level == 0)
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btrfs_item_key(buf, &disk_key, 0);
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else
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btrfs_node_key(buf, &disk_key, 0);
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cow = btrfs_alloc_tree_block(trans, root, 0, new_root_objectid,
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&disk_key, level, buf->start, 0,
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BTRFS_NESTING_NEW_ROOT);
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if (IS_ERR(cow))
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return PTR_ERR(cow);
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copy_extent_buffer_full(cow, buf);
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btrfs_set_header_bytenr(cow, cow->start);
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btrfs_set_header_generation(cow, trans->transid);
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btrfs_set_header_backref_rev(cow, BTRFS_MIXED_BACKREF_REV);
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btrfs_clear_header_flag(cow, BTRFS_HEADER_FLAG_WRITTEN |
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BTRFS_HEADER_FLAG_RELOC);
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if (new_root_objectid == BTRFS_TREE_RELOC_OBJECTID)
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btrfs_set_header_flag(cow, BTRFS_HEADER_FLAG_RELOC);
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else
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btrfs_set_header_owner(cow, new_root_objectid);
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write_extent_buffer_fsid(cow, fs_info->fs_devices->metadata_uuid);
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WARN_ON(btrfs_header_generation(buf) > trans->transid);
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if (new_root_objectid == BTRFS_TREE_RELOC_OBJECTID)
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ret = btrfs_inc_ref(trans, root, cow, 1);
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else
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ret = btrfs_inc_ref(trans, root, cow, 0);
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if (ret) {
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btrfs_tree_unlock(cow);
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free_extent_buffer(cow);
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btrfs_abort_transaction(trans, ret);
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return ret;
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}
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btrfs_mark_buffer_dirty(cow);
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*cow_ret = cow;
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return 0;
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}
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/*
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* check if the tree block can be shared by multiple trees
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*/
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int btrfs_block_can_be_shared(struct btrfs_root *root,
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struct extent_buffer *buf)
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{
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/*
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* Tree blocks not in shareable trees and tree roots are never shared.
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* If a block was allocated after the last snapshot and the block was
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* not allocated by tree relocation, we know the block is not shared.
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*/
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if (test_bit(BTRFS_ROOT_SHAREABLE, &root->state) &&
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buf != root->node && buf != root->commit_root &&
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(btrfs_header_generation(buf) <=
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btrfs_root_last_snapshot(&root->root_item) ||
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btrfs_header_flag(buf, BTRFS_HEADER_FLAG_RELOC)))
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return 1;
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return 0;
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}
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static noinline int update_ref_for_cow(struct btrfs_trans_handle *trans,
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struct btrfs_root *root,
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struct extent_buffer *buf,
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struct extent_buffer *cow,
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int *last_ref)
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{
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struct btrfs_fs_info *fs_info = root->fs_info;
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u64 refs;
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u64 owner;
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u64 flags;
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u64 new_flags = 0;
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int ret;
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/*
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* Backrefs update rules:
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*
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* Always use full backrefs for extent pointers in tree block
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* allocated by tree relocation.
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*
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* If a shared tree block is no longer referenced by its owner
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* tree (btrfs_header_owner(buf) == root->root_key.objectid),
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* use full backrefs for extent pointers in tree block.
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*
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* If a tree block is been relocating
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* (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID),
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* use full backrefs for extent pointers in tree block.
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* The reason for this is some operations (such as drop tree)
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* are only allowed for blocks use full backrefs.
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*/
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if (btrfs_block_can_be_shared(root, buf)) {
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ret = btrfs_lookup_extent_info(trans, fs_info, buf->start,
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btrfs_header_level(buf), 1,
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&refs, &flags);
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if (ret)
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return ret;
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if (refs == 0) {
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ret = -EROFS;
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btrfs_handle_fs_error(fs_info, ret, NULL);
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return ret;
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}
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} else {
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refs = 1;
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if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID ||
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btrfs_header_backref_rev(buf) < BTRFS_MIXED_BACKREF_REV)
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flags = BTRFS_BLOCK_FLAG_FULL_BACKREF;
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else
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flags = 0;
|
|
}
|
|
|
|
owner = btrfs_header_owner(buf);
|
|
BUG_ON(owner == BTRFS_TREE_RELOC_OBJECTID &&
|
|
!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF));
|
|
|
|
if (refs > 1) {
|
|
if ((owner == root->root_key.objectid ||
|
|
root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) &&
|
|
!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)) {
|
|
ret = btrfs_inc_ref(trans, root, buf, 1);
|
|
if (ret)
|
|
return ret;
|
|
|
|
if (root->root_key.objectid ==
|
|
BTRFS_TREE_RELOC_OBJECTID) {
|
|
ret = btrfs_dec_ref(trans, root, buf, 0);
|
|
if (ret)
|
|
return ret;
|
|
ret = btrfs_inc_ref(trans, root, cow, 1);
|
|
if (ret)
|
|
return ret;
|
|
}
|
|
new_flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
|
|
} else {
|
|
|
|
if (root->root_key.objectid ==
|
|
BTRFS_TREE_RELOC_OBJECTID)
|
|
ret = btrfs_inc_ref(trans, root, cow, 1);
|
|
else
|
|
ret = btrfs_inc_ref(trans, root, cow, 0);
|
|
if (ret)
|
|
return ret;
|
|
}
|
|
if (new_flags != 0) {
|
|
int level = btrfs_header_level(buf);
|
|
|
|
ret = btrfs_set_disk_extent_flags(trans, buf,
|
|
new_flags, level);
|
|
if (ret)
|
|
return ret;
|
|
}
|
|
} else {
|
|
if (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
|
|
if (root->root_key.objectid ==
|
|
BTRFS_TREE_RELOC_OBJECTID)
|
|
ret = btrfs_inc_ref(trans, root, cow, 1);
|
|
else
|
|
ret = btrfs_inc_ref(trans, root, cow, 0);
|
|
if (ret)
|
|
return ret;
|
|
ret = btrfs_dec_ref(trans, root, buf, 1);
|
|
if (ret)
|
|
return ret;
|
|
}
|
|
btrfs_clear_buffer_dirty(trans, buf);
|
|
*last_ref = 1;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* does the dirty work in cow of a single block. The parent block (if
|
|
* supplied) is updated to point to the new cow copy. The new buffer is marked
|
|
* dirty and returned locked. If you modify the block it needs to be marked
|
|
* dirty again.
|
|
*
|
|
* search_start -- an allocation hint for the new block
|
|
*
|
|
* empty_size -- a hint that you plan on doing more cow. This is the size in
|
|
* bytes the allocator should try to find free next to the block it returns.
|
|
* This is just a hint and may be ignored by the allocator.
|
|
*/
|
|
static noinline int __btrfs_cow_block(struct btrfs_trans_handle *trans,
|
|
struct btrfs_root *root,
|
|
struct extent_buffer *buf,
|
|
struct extent_buffer *parent, int parent_slot,
|
|
struct extent_buffer **cow_ret,
|
|
u64 search_start, u64 empty_size,
|
|
enum btrfs_lock_nesting nest)
|
|
{
|
|
struct btrfs_fs_info *fs_info = root->fs_info;
|
|
struct btrfs_disk_key disk_key;
|
|
struct extent_buffer *cow;
|
|
int level, ret;
|
|
int last_ref = 0;
|
|
int unlock_orig = 0;
|
|
u64 parent_start = 0;
|
|
|
|
if (*cow_ret == buf)
|
|
unlock_orig = 1;
|
|
|
|
btrfs_assert_tree_write_locked(buf);
|
|
|
|
WARN_ON(test_bit(BTRFS_ROOT_SHAREABLE, &root->state) &&
|
|
trans->transid != fs_info->running_transaction->transid);
|
|
WARN_ON(test_bit(BTRFS_ROOT_SHAREABLE, &root->state) &&
|
|
trans->transid != root->last_trans);
|
|
|
|
level = btrfs_header_level(buf);
|
|
|
|
if (level == 0)
|
|
btrfs_item_key(buf, &disk_key, 0);
|
|
else
|
|
btrfs_node_key(buf, &disk_key, 0);
|
|
|
|
if ((root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) && parent)
|
|
parent_start = parent->start;
|
|
|
|
cow = btrfs_alloc_tree_block(trans, root, parent_start,
|
|
root->root_key.objectid, &disk_key, level,
|
|
search_start, empty_size, nest);
|
|
if (IS_ERR(cow))
|
|
return PTR_ERR(cow);
|
|
|
|
/* cow is set to blocking by btrfs_init_new_buffer */
|
|
|
|
copy_extent_buffer_full(cow, buf);
|
|
btrfs_set_header_bytenr(cow, cow->start);
|
|
btrfs_set_header_generation(cow, trans->transid);
|
|
btrfs_set_header_backref_rev(cow, BTRFS_MIXED_BACKREF_REV);
|
|
btrfs_clear_header_flag(cow, BTRFS_HEADER_FLAG_WRITTEN |
|
|
BTRFS_HEADER_FLAG_RELOC);
|
|
if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
|
|
btrfs_set_header_flag(cow, BTRFS_HEADER_FLAG_RELOC);
|
|
else
|
|
btrfs_set_header_owner(cow, root->root_key.objectid);
|
|
|
|
write_extent_buffer_fsid(cow, fs_info->fs_devices->metadata_uuid);
|
|
|
|
ret = update_ref_for_cow(trans, root, buf, cow, &last_ref);
|
|
if (ret) {
|
|
btrfs_tree_unlock(cow);
|
|
free_extent_buffer(cow);
|
|
btrfs_abort_transaction(trans, ret);
|
|
return ret;
|
|
}
|
|
|
|
if (test_bit(BTRFS_ROOT_SHAREABLE, &root->state)) {
|
|
ret = btrfs_reloc_cow_block(trans, root, buf, cow);
|
|
if (ret) {
|
|
btrfs_tree_unlock(cow);
|
|
free_extent_buffer(cow);
|
|
btrfs_abort_transaction(trans, ret);
|
|
return ret;
|
|
}
|
|
}
|
|
|
|
if (buf == root->node) {
|
|
WARN_ON(parent && parent != buf);
|
|
if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID ||
|
|
btrfs_header_backref_rev(buf) < BTRFS_MIXED_BACKREF_REV)
|
|
parent_start = buf->start;
|
|
|
|
atomic_inc(&cow->refs);
|
|
ret = btrfs_tree_mod_log_insert_root(root->node, cow, true);
|
|
BUG_ON(ret < 0);
|
|
rcu_assign_pointer(root->node, cow);
|
|
|
|
btrfs_free_tree_block(trans, btrfs_root_id(root), buf,
|
|
parent_start, last_ref);
|
|
free_extent_buffer(buf);
|
|
add_root_to_dirty_list(root);
|
|
} else {
|
|
WARN_ON(trans->transid != btrfs_header_generation(parent));
|
|
btrfs_tree_mod_log_insert_key(parent, parent_slot,
|
|
BTRFS_MOD_LOG_KEY_REPLACE);
|
|
btrfs_set_node_blockptr(parent, parent_slot,
|
|
cow->start);
|
|
btrfs_set_node_ptr_generation(parent, parent_slot,
|
|
trans->transid);
|
|
btrfs_mark_buffer_dirty(parent);
|
|
if (last_ref) {
|
|
ret = btrfs_tree_mod_log_free_eb(buf);
|
|
if (ret) {
|
|
btrfs_tree_unlock(cow);
|
|
free_extent_buffer(cow);
|
|
btrfs_abort_transaction(trans, ret);
|
|
return ret;
|
|
}
|
|
}
|
|
btrfs_free_tree_block(trans, btrfs_root_id(root), buf,
|
|
parent_start, last_ref);
|
|
}
|
|
if (unlock_orig)
|
|
btrfs_tree_unlock(buf);
|
|
free_extent_buffer_stale(buf);
|
|
btrfs_mark_buffer_dirty(cow);
|
|
*cow_ret = cow;
|
|
return 0;
|
|
}
|
|
|
|
static inline int should_cow_block(struct btrfs_trans_handle *trans,
|
|
struct btrfs_root *root,
|
|
struct extent_buffer *buf)
|
|
{
|
|
if (btrfs_is_testing(root->fs_info))
|
|
return 0;
|
|
|
|
/* Ensure we can see the FORCE_COW bit */
|
|
smp_mb__before_atomic();
|
|
|
|
/*
|
|
* We do not need to cow a block if
|
|
* 1) this block is not created or changed in this transaction;
|
|
* 2) this block does not belong to TREE_RELOC tree;
|
|
* 3) the root is not forced COW.
|
|
*
|
|
* What is forced COW:
|
|
* when we create snapshot during committing the transaction,
|
|
* after we've finished copying src root, we must COW the shared
|
|
* block to ensure the metadata consistency.
|
|
*/
|
|
if (btrfs_header_generation(buf) == trans->transid &&
|
|
!btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN) &&
|
|
!(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID &&
|
|
btrfs_header_flag(buf, BTRFS_HEADER_FLAG_RELOC)) &&
|
|
!test_bit(BTRFS_ROOT_FORCE_COW, &root->state))
|
|
return 0;
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* cows a single block, see __btrfs_cow_block for the real work.
|
|
* This version of it has extra checks so that a block isn't COWed more than
|
|
* once per transaction, as long as it hasn't been written yet
|
|
*/
|
|
noinline int btrfs_cow_block(struct btrfs_trans_handle *trans,
|
|
struct btrfs_root *root, struct extent_buffer *buf,
|
|
struct extent_buffer *parent, int parent_slot,
|
|
struct extent_buffer **cow_ret,
|
|
enum btrfs_lock_nesting nest)
|
|
{
|
|
struct btrfs_fs_info *fs_info = root->fs_info;
|
|
u64 search_start;
|
|
int ret;
|
|
|
|
if (test_bit(BTRFS_ROOT_DELETING, &root->state))
|
|
btrfs_err(fs_info,
|
|
"COW'ing blocks on a fs root that's being dropped");
|
|
|
|
if (trans->transaction != fs_info->running_transaction)
|
|
WARN(1, KERN_CRIT "trans %llu running %llu\n",
|
|
trans->transid,
|
|
fs_info->running_transaction->transid);
|
|
|
|
if (trans->transid != fs_info->generation)
|
|
WARN(1, KERN_CRIT "trans %llu running %llu\n",
|
|
trans->transid, fs_info->generation);
|
|
|
|
if (!should_cow_block(trans, root, buf)) {
|
|
*cow_ret = buf;
|
|
return 0;
|
|
}
|
|
|
|
search_start = buf->start & ~((u64)SZ_1G - 1);
|
|
|
|
/*
|
|
* Before CoWing this block for later modification, check if it's
|
|
* the subtree root and do the delayed subtree trace if needed.
|
|
*
|
|
* Also We don't care about the error, as it's handled internally.
|
|
*/
|
|
btrfs_qgroup_trace_subtree_after_cow(trans, root, buf);
|
|
ret = __btrfs_cow_block(trans, root, buf, parent,
|
|
parent_slot, cow_ret, search_start, 0, nest);
|
|
|
|
trace_btrfs_cow_block(root, buf, *cow_ret);
|
|
|
|
return ret;
|
|
}
|
|
ALLOW_ERROR_INJECTION(btrfs_cow_block, ERRNO);
|
|
|
|
/*
|
|
* helper function for defrag to decide if two blocks pointed to by a
|
|
* node are actually close by
|
|
*/
|
|
static int close_blocks(u64 blocknr, u64 other, u32 blocksize)
|
|
{
|
|
if (blocknr < other && other - (blocknr + blocksize) < 32768)
|
|
return 1;
|
|
if (blocknr > other && blocknr - (other + blocksize) < 32768)
|
|
return 1;
|
|
return 0;
|
|
}
|
|
|
|
#ifdef __LITTLE_ENDIAN
|
|
|
|
/*
|
|
* Compare two keys, on little-endian the disk order is same as CPU order and
|
|
* we can avoid the conversion.
|
|
*/
|
|
static int comp_keys(const struct btrfs_disk_key *disk_key,
|
|
const struct btrfs_key *k2)
|
|
{
|
|
const struct btrfs_key *k1 = (const struct btrfs_key *)disk_key;
|
|
|
|
return btrfs_comp_cpu_keys(k1, k2);
|
|
}
|
|
|
|
#else
|
|
|
|
/*
|
|
* compare two keys in a memcmp fashion
|
|
*/
|
|
static int comp_keys(const struct btrfs_disk_key *disk,
|
|
const struct btrfs_key *k2)
|
|
{
|
|
struct btrfs_key k1;
|
|
|
|
btrfs_disk_key_to_cpu(&k1, disk);
|
|
|
|
return btrfs_comp_cpu_keys(&k1, k2);
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* same as comp_keys only with two btrfs_key's
|
|
*/
|
|
int __pure btrfs_comp_cpu_keys(const struct btrfs_key *k1, const struct btrfs_key *k2)
|
|
{
|
|
if (k1->objectid > k2->objectid)
|
|
return 1;
|
|
if (k1->objectid < k2->objectid)
|
|
return -1;
|
|
if (k1->type > k2->type)
|
|
return 1;
|
|
if (k1->type < k2->type)
|
|
return -1;
|
|
if (k1->offset > k2->offset)
|
|
return 1;
|
|
if (k1->offset < k2->offset)
|
|
return -1;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* this is used by the defrag code to go through all the
|
|
* leaves pointed to by a node and reallocate them so that
|
|
* disk order is close to key order
|
|
*/
|
|
int btrfs_realloc_node(struct btrfs_trans_handle *trans,
|
|
struct btrfs_root *root, struct extent_buffer *parent,
|
|
int start_slot, u64 *last_ret,
|
|
struct btrfs_key *progress)
|
|
{
|
|
struct btrfs_fs_info *fs_info = root->fs_info;
|
|
struct extent_buffer *cur;
|
|
u64 blocknr;
|
|
u64 search_start = *last_ret;
|
|
u64 last_block = 0;
|
|
u64 other;
|
|
u32 parent_nritems;
|
|
int end_slot;
|
|
int i;
|
|
int err = 0;
|
|
u32 blocksize;
|
|
int progress_passed = 0;
|
|
struct btrfs_disk_key disk_key;
|
|
|
|
WARN_ON(trans->transaction != fs_info->running_transaction);
|
|
WARN_ON(trans->transid != fs_info->generation);
|
|
|
|
parent_nritems = btrfs_header_nritems(parent);
|
|
blocksize = fs_info->nodesize;
|
|
end_slot = parent_nritems - 1;
|
|
|
|
if (parent_nritems <= 1)
|
|
return 0;
|
|
|
|
for (i = start_slot; i <= end_slot; i++) {
|
|
int close = 1;
|
|
|
|
btrfs_node_key(parent, &disk_key, i);
|
|
if (!progress_passed && comp_keys(&disk_key, progress) < 0)
|
|
continue;
|
|
|
|
progress_passed = 1;
|
|
blocknr = btrfs_node_blockptr(parent, i);
|
|
if (last_block == 0)
|
|
last_block = blocknr;
|
|
|
|
if (i > 0) {
|
|
other = btrfs_node_blockptr(parent, i - 1);
|
|
close = close_blocks(blocknr, other, blocksize);
|
|
}
|
|
if (!close && i < end_slot) {
|
|
other = btrfs_node_blockptr(parent, i + 1);
|
|
close = close_blocks(blocknr, other, blocksize);
|
|
}
|
|
if (close) {
|
|
last_block = blocknr;
|
|
continue;
|
|
}
|
|
|
|
cur = btrfs_read_node_slot(parent, i);
|
|
if (IS_ERR(cur))
|
|
return PTR_ERR(cur);
|
|
if (search_start == 0)
|
|
search_start = last_block;
|
|
|
|
btrfs_tree_lock(cur);
|
|
err = __btrfs_cow_block(trans, root, cur, parent, i,
|
|
&cur, search_start,
|
|
min(16 * blocksize,
|
|
(end_slot - i) * blocksize),
|
|
BTRFS_NESTING_COW);
|
|
if (err) {
|
|
btrfs_tree_unlock(cur);
|
|
free_extent_buffer(cur);
|
|
break;
|
|
}
|
|
search_start = cur->start;
|
|
last_block = cur->start;
|
|
*last_ret = search_start;
|
|
btrfs_tree_unlock(cur);
|
|
free_extent_buffer(cur);
|
|
}
|
|
return err;
|
|
}
|
|
|
|
/*
|
|
* Search for a key in the given extent_buffer.
|
|
*
|
|
* The lower boundary for the search is specified by the slot number @first_slot.
|
|
* Use a value of 0 to search over the whole extent buffer.
|
|
*
|
|
* The slot in the extent buffer is returned via @slot. If the key exists in the
|
|
* extent buffer, then @slot will point to the slot where the key is, otherwise
|
|
* it points to the slot where you would insert the key.
|
|
*
|
|
* Slot may point to the total number of items (i.e. one position beyond the last
|
|
* key) if the key is bigger than the last key in the extent buffer.
|
|
*/
|
|
int btrfs_generic_bin_search(struct extent_buffer *eb, int first_slot,
|
|
const struct btrfs_key *key, int *slot)
|
|
{
|
|
unsigned long p;
|
|
int item_size;
|
|
/*
|
|
* Use unsigned types for the low and high slots, so that we get a more
|
|
* efficient division in the search loop below.
|
|
*/
|
|
u32 low = first_slot;
|
|
u32 high = btrfs_header_nritems(eb);
|
|
int ret;
|
|
const int key_size = sizeof(struct btrfs_disk_key);
|
|
|
|
if (unlikely(low > high)) {
|
|
btrfs_err(eb->fs_info,
|
|
"%s: low (%u) > high (%u) eb %llu owner %llu level %d",
|
|
__func__, low, high, eb->start,
|
|
btrfs_header_owner(eb), btrfs_header_level(eb));
|
|
return -EINVAL;
|
|
}
|
|
|
|
if (btrfs_header_level(eb) == 0) {
|
|
p = offsetof(struct btrfs_leaf, items);
|
|
item_size = sizeof(struct btrfs_item);
|
|
} else {
|
|
p = offsetof(struct btrfs_node, ptrs);
|
|
item_size = sizeof(struct btrfs_key_ptr);
|
|
}
|
|
|
|
while (low < high) {
|
|
unsigned long oip;
|
|
unsigned long offset;
|
|
struct btrfs_disk_key *tmp;
|
|
struct btrfs_disk_key unaligned;
|
|
int mid;
|
|
|
|
mid = (low + high) / 2;
|
|
offset = p + mid * item_size;
|
|
oip = offset_in_page(offset);
|
|
|
|
if (oip + key_size <= PAGE_SIZE) {
|
|
const unsigned long idx = get_eb_page_index(offset);
|
|
char *kaddr = page_address(eb->pages[idx]);
|
|
|
|
oip = get_eb_offset_in_page(eb, offset);
|
|
tmp = (struct btrfs_disk_key *)(kaddr + oip);
|
|
} else {
|
|
read_extent_buffer(eb, &unaligned, offset, key_size);
|
|
tmp = &unaligned;
|
|
}
|
|
|
|
ret = comp_keys(tmp, key);
|
|
|
|
if (ret < 0)
|
|
low = mid + 1;
|
|
else if (ret > 0)
|
|
high = mid;
|
|
else {
|
|
*slot = mid;
|
|
return 0;
|
|
}
|
|
}
|
|
*slot = low;
|
|
return 1;
|
|
}
|
|
|
|
static void root_add_used(struct btrfs_root *root, u32 size)
|
|
{
|
|
spin_lock(&root->accounting_lock);
|
|
btrfs_set_root_used(&root->root_item,
|
|
btrfs_root_used(&root->root_item) + size);
|
|
spin_unlock(&root->accounting_lock);
|
|
}
|
|
|
|
static void root_sub_used(struct btrfs_root *root, u32 size)
|
|
{
|
|
spin_lock(&root->accounting_lock);
|
|
btrfs_set_root_used(&root->root_item,
|
|
btrfs_root_used(&root->root_item) - size);
|
|
spin_unlock(&root->accounting_lock);
|
|
}
|
|
|
|
/* given a node and slot number, this reads the blocks it points to. The
|
|
* extent buffer is returned with a reference taken (but unlocked).
|
|
*/
|
|
struct extent_buffer *btrfs_read_node_slot(struct extent_buffer *parent,
|
|
int slot)
|
|
{
|
|
int level = btrfs_header_level(parent);
|
|
struct btrfs_tree_parent_check check = { 0 };
|
|
struct extent_buffer *eb;
|
|
|
|
if (slot < 0 || slot >= btrfs_header_nritems(parent))
|
|
return ERR_PTR(-ENOENT);
|
|
|
|
BUG_ON(level == 0);
|
|
|
|
check.level = level - 1;
|
|
check.transid = btrfs_node_ptr_generation(parent, slot);
|
|
check.owner_root = btrfs_header_owner(parent);
|
|
check.has_first_key = true;
|
|
btrfs_node_key_to_cpu(parent, &check.first_key, slot);
|
|
|
|
eb = read_tree_block(parent->fs_info, btrfs_node_blockptr(parent, slot),
|
|
&check);
|
|
if (IS_ERR(eb))
|
|
return eb;
|
|
if (!extent_buffer_uptodate(eb)) {
|
|
free_extent_buffer(eb);
|
|
return ERR_PTR(-EIO);
|
|
}
|
|
|
|
return eb;
|
|
}
|
|
|
|
/*
|
|
* node level balancing, used to make sure nodes are in proper order for
|
|
* item deletion. We balance from the top down, so we have to make sure
|
|
* that a deletion won't leave an node completely empty later on.
|
|
*/
|
|
static noinline int balance_level(struct btrfs_trans_handle *trans,
|
|
struct btrfs_root *root,
|
|
struct btrfs_path *path, int level)
|
|
{
|
|
struct btrfs_fs_info *fs_info = root->fs_info;
|
|
struct extent_buffer *right = NULL;
|
|
struct extent_buffer *mid;
|
|
struct extent_buffer *left = NULL;
|
|
struct extent_buffer *parent = NULL;
|
|
int ret = 0;
|
|
int wret;
|
|
int pslot;
|
|
int orig_slot = path->slots[level];
|
|
u64 orig_ptr;
|
|
|
|
ASSERT(level > 0);
|
|
|
|
mid = path->nodes[level];
|
|
|
|
WARN_ON(path->locks[level] != BTRFS_WRITE_LOCK);
|
|
WARN_ON(btrfs_header_generation(mid) != trans->transid);
|
|
|
|
orig_ptr = btrfs_node_blockptr(mid, orig_slot);
|
|
|
|
if (level < BTRFS_MAX_LEVEL - 1) {
|
|
parent = path->nodes[level + 1];
|
|
pslot = path->slots[level + 1];
|
|
}
|
|
|
|
/*
|
|
* deal with the case where there is only one pointer in the root
|
|
* by promoting the node below to a root
|
|
*/
|
|
if (!parent) {
|
|
struct extent_buffer *child;
|
|
|
|
if (btrfs_header_nritems(mid) != 1)
|
|
return 0;
|
|
|
|
/* promote the child to a root */
|
|
child = btrfs_read_node_slot(mid, 0);
|
|
if (IS_ERR(child)) {
|
|
ret = PTR_ERR(child);
|
|
btrfs_handle_fs_error(fs_info, ret, NULL);
|
|
goto enospc;
|
|
}
|
|
|
|
btrfs_tree_lock(child);
|
|
ret = btrfs_cow_block(trans, root, child, mid, 0, &child,
|
|
BTRFS_NESTING_COW);
|
|
if (ret) {
|
|
btrfs_tree_unlock(child);
|
|
free_extent_buffer(child);
|
|
goto enospc;
|
|
}
|
|
|
|
ret = btrfs_tree_mod_log_insert_root(root->node, child, true);
|
|
BUG_ON(ret < 0);
|
|
rcu_assign_pointer(root->node, child);
|
|
|
|
add_root_to_dirty_list(root);
|
|
btrfs_tree_unlock(child);
|
|
|
|
path->locks[level] = 0;
|
|
path->nodes[level] = NULL;
|
|
btrfs_clear_buffer_dirty(trans, mid);
|
|
btrfs_tree_unlock(mid);
|
|
/* once for the path */
|
|
free_extent_buffer(mid);
|
|
|
|
root_sub_used(root, mid->len);
|
|
btrfs_free_tree_block(trans, btrfs_root_id(root), mid, 0, 1);
|
|
/* once for the root ptr */
|
|
free_extent_buffer_stale(mid);
|
|
return 0;
|
|
}
|
|
if (btrfs_header_nritems(mid) >
|
|
BTRFS_NODEPTRS_PER_BLOCK(fs_info) / 4)
|
|
return 0;
|
|
|
|
left = btrfs_read_node_slot(parent, pslot - 1);
|
|
if (IS_ERR(left))
|
|
left = NULL;
|
|
|
|
if (left) {
|
|
__btrfs_tree_lock(left, BTRFS_NESTING_LEFT);
|
|
wret = btrfs_cow_block(trans, root, left,
|
|
parent, pslot - 1, &left,
|
|
BTRFS_NESTING_LEFT_COW);
|
|
if (wret) {
|
|
ret = wret;
|
|
goto enospc;
|
|
}
|
|
}
|
|
|
|
right = btrfs_read_node_slot(parent, pslot + 1);
|
|
if (IS_ERR(right))
|
|
right = NULL;
|
|
|
|
if (right) {
|
|
__btrfs_tree_lock(right, BTRFS_NESTING_RIGHT);
|
|
wret = btrfs_cow_block(trans, root, right,
|
|
parent, pslot + 1, &right,
|
|
BTRFS_NESTING_RIGHT_COW);
|
|
if (wret) {
|
|
ret = wret;
|
|
goto enospc;
|
|
}
|
|
}
|
|
|
|
/* first, try to make some room in the middle buffer */
|
|
if (left) {
|
|
orig_slot += btrfs_header_nritems(left);
|
|
wret = push_node_left(trans, left, mid, 1);
|
|
if (wret < 0)
|
|
ret = wret;
|
|
}
|
|
|
|
/*
|
|
* then try to empty the right most buffer into the middle
|
|
*/
|
|
if (right) {
|
|
wret = push_node_left(trans, mid, right, 1);
|
|
if (wret < 0 && wret != -ENOSPC)
|
|
ret = wret;
|
|
if (btrfs_header_nritems(right) == 0) {
|
|
btrfs_clear_buffer_dirty(trans, right);
|
|
btrfs_tree_unlock(right);
|
|
del_ptr(root, path, level + 1, pslot + 1);
|
|
root_sub_used(root, right->len);
|
|
btrfs_free_tree_block(trans, btrfs_root_id(root), right,
|
|
0, 1);
|
|
free_extent_buffer_stale(right);
|
|
right = NULL;
|
|
} else {
|
|
struct btrfs_disk_key right_key;
|
|
btrfs_node_key(right, &right_key, 0);
|
|
ret = btrfs_tree_mod_log_insert_key(parent, pslot + 1,
|
|
BTRFS_MOD_LOG_KEY_REPLACE);
|
|
BUG_ON(ret < 0);
|
|
btrfs_set_node_key(parent, &right_key, pslot + 1);
|
|
btrfs_mark_buffer_dirty(parent);
|
|
}
|
|
}
|
|
if (btrfs_header_nritems(mid) == 1) {
|
|
/*
|
|
* we're not allowed to leave a node with one item in the
|
|
* tree during a delete. A deletion from lower in the tree
|
|
* could try to delete the only pointer in this node.
|
|
* So, pull some keys from the left.
|
|
* There has to be a left pointer at this point because
|
|
* otherwise we would have pulled some pointers from the
|
|
* right
|
|
*/
|
|
if (!left) {
|
|
ret = -EROFS;
|
|
btrfs_handle_fs_error(fs_info, ret, NULL);
|
|
goto enospc;
|
|
}
|
|
wret = balance_node_right(trans, mid, left);
|
|
if (wret < 0) {
|
|
ret = wret;
|
|
goto enospc;
|
|
}
|
|
if (wret == 1) {
|
|
wret = push_node_left(trans, left, mid, 1);
|
|
if (wret < 0)
|
|
ret = wret;
|
|
}
|
|
BUG_ON(wret == 1);
|
|
}
|
|
if (btrfs_header_nritems(mid) == 0) {
|
|
btrfs_clear_buffer_dirty(trans, mid);
|
|
btrfs_tree_unlock(mid);
|
|
del_ptr(root, path, level + 1, pslot);
|
|
root_sub_used(root, mid->len);
|
|
btrfs_free_tree_block(trans, btrfs_root_id(root), mid, 0, 1);
|
|
free_extent_buffer_stale(mid);
|
|
mid = NULL;
|
|
} else {
|
|
/* update the parent key to reflect our changes */
|
|
struct btrfs_disk_key mid_key;
|
|
btrfs_node_key(mid, &mid_key, 0);
|
|
ret = btrfs_tree_mod_log_insert_key(parent, pslot,
|
|
BTRFS_MOD_LOG_KEY_REPLACE);
|
|
BUG_ON(ret < 0);
|
|
btrfs_set_node_key(parent, &mid_key, pslot);
|
|
btrfs_mark_buffer_dirty(parent);
|
|
}
|
|
|
|
/* update the path */
|
|
if (left) {
|
|
if (btrfs_header_nritems(left) > orig_slot) {
|
|
atomic_inc(&left->refs);
|
|
/* left was locked after cow */
|
|
path->nodes[level] = left;
|
|
path->slots[level + 1] -= 1;
|
|
path->slots[level] = orig_slot;
|
|
if (mid) {
|
|
btrfs_tree_unlock(mid);
|
|
free_extent_buffer(mid);
|
|
}
|
|
} else {
|
|
orig_slot -= btrfs_header_nritems(left);
|
|
path->slots[level] = orig_slot;
|
|
}
|
|
}
|
|
/* double check we haven't messed things up */
|
|
if (orig_ptr !=
|
|
btrfs_node_blockptr(path->nodes[level], path->slots[level]))
|
|
BUG();
|
|
enospc:
|
|
if (right) {
|
|
btrfs_tree_unlock(right);
|
|
free_extent_buffer(right);
|
|
}
|
|
if (left) {
|
|
if (path->nodes[level] != left)
|
|
btrfs_tree_unlock(left);
|
|
free_extent_buffer(left);
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
/* Node balancing for insertion. Here we only split or push nodes around
|
|
* when they are completely full. This is also done top down, so we
|
|
* have to be pessimistic.
|
|
*/
|
|
static noinline int push_nodes_for_insert(struct btrfs_trans_handle *trans,
|
|
struct btrfs_root *root,
|
|
struct btrfs_path *path, int level)
|
|
{
|
|
struct btrfs_fs_info *fs_info = root->fs_info;
|
|
struct extent_buffer *right = NULL;
|
|
struct extent_buffer *mid;
|
|
struct extent_buffer *left = NULL;
|
|
struct extent_buffer *parent = NULL;
|
|
int ret = 0;
|
|
int wret;
|
|
int pslot;
|
|
int orig_slot = path->slots[level];
|
|
|
|
if (level == 0)
|
|
return 1;
|
|
|
|
mid = path->nodes[level];
|
|
WARN_ON(btrfs_header_generation(mid) != trans->transid);
|
|
|
|
if (level < BTRFS_MAX_LEVEL - 1) {
|
|
parent = path->nodes[level + 1];
|
|
pslot = path->slots[level + 1];
|
|
}
|
|
|
|
if (!parent)
|
|
return 1;
|
|
|
|
left = btrfs_read_node_slot(parent, pslot - 1);
|
|
if (IS_ERR(left))
|
|
left = NULL;
|
|
|
|
/* first, try to make some room in the middle buffer */
|
|
if (left) {
|
|
u32 left_nr;
|
|
|
|
__btrfs_tree_lock(left, BTRFS_NESTING_LEFT);
|
|
|
|
left_nr = btrfs_header_nritems(left);
|
|
if (left_nr >= BTRFS_NODEPTRS_PER_BLOCK(fs_info) - 1) {
|
|
wret = 1;
|
|
} else {
|
|
ret = btrfs_cow_block(trans, root, left, parent,
|
|
pslot - 1, &left,
|
|
BTRFS_NESTING_LEFT_COW);
|
|
if (ret)
|
|
wret = 1;
|
|
else {
|
|
wret = push_node_left(trans, left, mid, 0);
|
|
}
|
|
}
|
|
if (wret < 0)
|
|
ret = wret;
|
|
if (wret == 0) {
|
|
struct btrfs_disk_key disk_key;
|
|
orig_slot += left_nr;
|
|
btrfs_node_key(mid, &disk_key, 0);
|
|
ret = btrfs_tree_mod_log_insert_key(parent, pslot,
|
|
BTRFS_MOD_LOG_KEY_REPLACE);
|
|
BUG_ON(ret < 0);
|
|
btrfs_set_node_key(parent, &disk_key, pslot);
|
|
btrfs_mark_buffer_dirty(parent);
|
|
if (btrfs_header_nritems(left) > orig_slot) {
|
|
path->nodes[level] = left;
|
|
path->slots[level + 1] -= 1;
|
|
path->slots[level] = orig_slot;
|
|
btrfs_tree_unlock(mid);
|
|
free_extent_buffer(mid);
|
|
} else {
|
|
orig_slot -=
|
|
btrfs_header_nritems(left);
|
|
path->slots[level] = orig_slot;
|
|
btrfs_tree_unlock(left);
|
|
free_extent_buffer(left);
|
|
}
|
|
return 0;
|
|
}
|
|
btrfs_tree_unlock(left);
|
|
free_extent_buffer(left);
|
|
}
|
|
right = btrfs_read_node_slot(parent, pslot + 1);
|
|
if (IS_ERR(right))
|
|
right = NULL;
|
|
|
|
/*
|
|
* then try to empty the right most buffer into the middle
|
|
*/
|
|
if (right) {
|
|
u32 right_nr;
|
|
|
|
__btrfs_tree_lock(right, BTRFS_NESTING_RIGHT);
|
|
|
|
right_nr = btrfs_header_nritems(right);
|
|
if (right_nr >= BTRFS_NODEPTRS_PER_BLOCK(fs_info) - 1) {
|
|
wret = 1;
|
|
} else {
|
|
ret = btrfs_cow_block(trans, root, right,
|
|
parent, pslot + 1,
|
|
&right, BTRFS_NESTING_RIGHT_COW);
|
|
if (ret)
|
|
wret = 1;
|
|
else {
|
|
wret = balance_node_right(trans, right, mid);
|
|
}
|
|
}
|
|
if (wret < 0)
|
|
ret = wret;
|
|
if (wret == 0) {
|
|
struct btrfs_disk_key disk_key;
|
|
|
|
btrfs_node_key(right, &disk_key, 0);
|
|
ret = btrfs_tree_mod_log_insert_key(parent, pslot + 1,
|
|
BTRFS_MOD_LOG_KEY_REPLACE);
|
|
BUG_ON(ret < 0);
|
|
btrfs_set_node_key(parent, &disk_key, pslot + 1);
|
|
btrfs_mark_buffer_dirty(parent);
|
|
|
|
if (btrfs_header_nritems(mid) <= orig_slot) {
|
|
path->nodes[level] = right;
|
|
path->slots[level + 1] += 1;
|
|
path->slots[level] = orig_slot -
|
|
btrfs_header_nritems(mid);
|
|
btrfs_tree_unlock(mid);
|
|
free_extent_buffer(mid);
|
|
} else {
|
|
btrfs_tree_unlock(right);
|
|
free_extent_buffer(right);
|
|
}
|
|
return 0;
|
|
}
|
|
btrfs_tree_unlock(right);
|
|
free_extent_buffer(right);
|
|
}
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* readahead one full node of leaves, finding things that are close
|
|
* to the block in 'slot', and triggering ra on them.
|
|
*/
|
|
static void reada_for_search(struct btrfs_fs_info *fs_info,
|
|
struct btrfs_path *path,
|
|
int level, int slot, u64 objectid)
|
|
{
|
|
struct extent_buffer *node;
|
|
struct btrfs_disk_key disk_key;
|
|
u32 nritems;
|
|
u64 search;
|
|
u64 target;
|
|
u64 nread = 0;
|
|
u64 nread_max;
|
|
u32 nr;
|
|
u32 blocksize;
|
|
u32 nscan = 0;
|
|
|
|
if (level != 1 && path->reada != READA_FORWARD_ALWAYS)
|
|
return;
|
|
|
|
if (!path->nodes[level])
|
|
return;
|
|
|
|
node = path->nodes[level];
|
|
|
|
/*
|
|
* Since the time between visiting leaves is much shorter than the time
|
|
* between visiting nodes, limit read ahead of nodes to 1, to avoid too
|
|
* much IO at once (possibly random).
|
|
*/
|
|
if (path->reada == READA_FORWARD_ALWAYS) {
|
|
if (level > 1)
|
|
nread_max = node->fs_info->nodesize;
|
|
else
|
|
nread_max = SZ_128K;
|
|
} else {
|
|
nread_max = SZ_64K;
|
|
}
|
|
|
|
search = btrfs_node_blockptr(node, slot);
|
|
blocksize = fs_info->nodesize;
|
|
if (path->reada != READA_FORWARD_ALWAYS) {
|
|
struct extent_buffer *eb;
|
|
|
|
eb = find_extent_buffer(fs_info, search);
|
|
if (eb) {
|
|
free_extent_buffer(eb);
|
|
return;
|
|
}
|
|
}
|
|
|
|
target = search;
|
|
|
|
nritems = btrfs_header_nritems(node);
|
|
nr = slot;
|
|
|
|
while (1) {
|
|
if (path->reada == READA_BACK) {
|
|
if (nr == 0)
|
|
break;
|
|
nr--;
|
|
} else if (path->reada == READA_FORWARD ||
|
|
path->reada == READA_FORWARD_ALWAYS) {
|
|
nr++;
|
|
if (nr >= nritems)
|
|
break;
|
|
}
|
|
if (path->reada == READA_BACK && objectid) {
|
|
btrfs_node_key(node, &disk_key, nr);
|
|
if (btrfs_disk_key_objectid(&disk_key) != objectid)
|
|
break;
|
|
}
|
|
search = btrfs_node_blockptr(node, nr);
|
|
if (path->reada == READA_FORWARD_ALWAYS ||
|
|
(search <= target && target - search <= 65536) ||
|
|
(search > target && search - target <= 65536)) {
|
|
btrfs_readahead_node_child(node, nr);
|
|
nread += blocksize;
|
|
}
|
|
nscan++;
|
|
if (nread > nread_max || nscan > 32)
|
|
break;
|
|
}
|
|
}
|
|
|
|
static noinline void reada_for_balance(struct btrfs_path *path, int level)
|
|
{
|
|
struct extent_buffer *parent;
|
|
int slot;
|
|
int nritems;
|
|
|
|
parent = path->nodes[level + 1];
|
|
if (!parent)
|
|
return;
|
|
|
|
nritems = btrfs_header_nritems(parent);
|
|
slot = path->slots[level + 1];
|
|
|
|
if (slot > 0)
|
|
btrfs_readahead_node_child(parent, slot - 1);
|
|
if (slot + 1 < nritems)
|
|
btrfs_readahead_node_child(parent, slot + 1);
|
|
}
|
|
|
|
|
|
/*
|
|
* when we walk down the tree, it is usually safe to unlock the higher layers
|
|
* in the tree. The exceptions are when our path goes through slot 0, because
|
|
* operations on the tree might require changing key pointers higher up in the
|
|
* tree.
|
|
*
|
|
* callers might also have set path->keep_locks, which tells this code to keep
|
|
* the lock if the path points to the last slot in the block. This is part of
|
|
* walking through the tree, and selecting the next slot in the higher block.
|
|
*
|
|
* lowest_unlock sets the lowest level in the tree we're allowed to unlock. so
|
|
* if lowest_unlock is 1, level 0 won't be unlocked
|
|
*/
|
|
static noinline void unlock_up(struct btrfs_path *path, int level,
|
|
int lowest_unlock, int min_write_lock_level,
|
|
int *write_lock_level)
|
|
{
|
|
int i;
|
|
int skip_level = level;
|
|
bool check_skip = true;
|
|
|
|
for (i = level; i < BTRFS_MAX_LEVEL; i++) {
|
|
if (!path->nodes[i])
|
|
break;
|
|
if (!path->locks[i])
|
|
break;
|
|
|
|
if (check_skip) {
|
|
if (path->slots[i] == 0) {
|
|
skip_level = i + 1;
|
|
continue;
|
|
}
|
|
|
|
if (path->keep_locks) {
|
|
u32 nritems;
|
|
|
|
nritems = btrfs_header_nritems(path->nodes[i]);
|
|
if (nritems < 1 || path->slots[i] >= nritems - 1) {
|
|
skip_level = i + 1;
|
|
continue;
|
|
}
|
|
}
|
|
}
|
|
|
|
if (i >= lowest_unlock && i > skip_level) {
|
|
check_skip = false;
|
|
btrfs_tree_unlock_rw(path->nodes[i], path->locks[i]);
|
|
path->locks[i] = 0;
|
|
if (write_lock_level &&
|
|
i > min_write_lock_level &&
|
|
i <= *write_lock_level) {
|
|
*write_lock_level = i - 1;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Helper function for btrfs_search_slot() and other functions that do a search
|
|
* on a btree. The goal is to find a tree block in the cache (the radix tree at
|
|
* fs_info->buffer_radix), but if we can't find it, or it's not up to date, read
|
|
* its pages from disk.
|
|
*
|
|
* Returns -EAGAIN, with the path unlocked, if the caller needs to repeat the
|
|
* whole btree search, starting again from the current root node.
|
|
*/
|
|
static int
|
|
read_block_for_search(struct btrfs_root *root, struct btrfs_path *p,
|
|
struct extent_buffer **eb_ret, int level, int slot,
|
|
const struct btrfs_key *key)
|
|
{
|
|
struct btrfs_fs_info *fs_info = root->fs_info;
|
|
struct btrfs_tree_parent_check check = { 0 };
|
|
u64 blocknr;
|
|
u64 gen;
|
|
struct extent_buffer *tmp;
|
|
int ret;
|
|
int parent_level;
|
|
bool unlock_up;
|
|
|
|
unlock_up = ((level + 1 < BTRFS_MAX_LEVEL) && p->locks[level + 1]);
|
|
blocknr = btrfs_node_blockptr(*eb_ret, slot);
|
|
gen = btrfs_node_ptr_generation(*eb_ret, slot);
|
|
parent_level = btrfs_header_level(*eb_ret);
|
|
btrfs_node_key_to_cpu(*eb_ret, &check.first_key, slot);
|
|
check.has_first_key = true;
|
|
check.level = parent_level - 1;
|
|
check.transid = gen;
|
|
check.owner_root = root->root_key.objectid;
|
|
|
|
/*
|
|
* If we need to read an extent buffer from disk and we are holding locks
|
|
* on upper level nodes, we unlock all the upper nodes before reading the
|
|
* extent buffer, and then return -EAGAIN to the caller as it needs to
|
|
* restart the search. We don't release the lock on the current level
|
|
* because we need to walk this node to figure out which blocks to read.
|
|
*/
|
|
tmp = find_extent_buffer(fs_info, blocknr);
|
|
if (tmp) {
|
|
if (p->reada == READA_FORWARD_ALWAYS)
|
|
reada_for_search(fs_info, p, level, slot, key->objectid);
|
|
|
|
/* first we do an atomic uptodate check */
|
|
if (btrfs_buffer_uptodate(tmp, gen, 1) > 0) {
|
|
/*
|
|
* Do extra check for first_key, eb can be stale due to
|
|
* being cached, read from scrub, or have multiple
|
|
* parents (shared tree blocks).
|
|
*/
|
|
if (btrfs_verify_level_key(tmp,
|
|
parent_level - 1, &check.first_key, gen)) {
|
|
free_extent_buffer(tmp);
|
|
return -EUCLEAN;
|
|
}
|
|
*eb_ret = tmp;
|
|
return 0;
|
|
}
|
|
|
|
if (p->nowait) {
|
|
free_extent_buffer(tmp);
|
|
return -EAGAIN;
|
|
}
|
|
|
|
if (unlock_up)
|
|
btrfs_unlock_up_safe(p, level + 1);
|
|
|
|
/* now we're allowed to do a blocking uptodate check */
|
|
ret = btrfs_read_extent_buffer(tmp, &check);
|
|
if (ret) {
|
|
free_extent_buffer(tmp);
|
|
btrfs_release_path(p);
|
|
return -EIO;
|
|
}
|
|
if (btrfs_check_eb_owner(tmp, root->root_key.objectid)) {
|
|
free_extent_buffer(tmp);
|
|
btrfs_release_path(p);
|
|
return -EUCLEAN;
|
|
}
|
|
|
|
if (unlock_up)
|
|
ret = -EAGAIN;
|
|
|
|
goto out;
|
|
} else if (p->nowait) {
|
|
return -EAGAIN;
|
|
}
|
|
|
|
if (unlock_up) {
|
|
btrfs_unlock_up_safe(p, level + 1);
|
|
ret = -EAGAIN;
|
|
} else {
|
|
ret = 0;
|
|
}
|
|
|
|
if (p->reada != READA_NONE)
|
|
reada_for_search(fs_info, p, level, slot, key->objectid);
|
|
|
|
tmp = read_tree_block(fs_info, blocknr, &check);
|
|
if (IS_ERR(tmp)) {
|
|
btrfs_release_path(p);
|
|
return PTR_ERR(tmp);
|
|
}
|
|
/*
|
|
* If the read above didn't mark this buffer up to date,
|
|
* it will never end up being up to date. Set ret to EIO now
|
|
* and give up so that our caller doesn't loop forever
|
|
* on our EAGAINs.
|
|
*/
|
|
if (!extent_buffer_uptodate(tmp))
|
|
ret = -EIO;
|
|
|
|
out:
|
|
if (ret == 0) {
|
|
*eb_ret = tmp;
|
|
} else {
|
|
free_extent_buffer(tmp);
|
|
btrfs_release_path(p);
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* helper function for btrfs_search_slot. This does all of the checks
|
|
* for node-level blocks and does any balancing required based on
|
|
* the ins_len.
|
|
*
|
|
* If no extra work was required, zero is returned. If we had to
|
|
* drop the path, -EAGAIN is returned and btrfs_search_slot must
|
|
* start over
|
|
*/
|
|
static int
|
|
setup_nodes_for_search(struct btrfs_trans_handle *trans,
|
|
struct btrfs_root *root, struct btrfs_path *p,
|
|
struct extent_buffer *b, int level, int ins_len,
|
|
int *write_lock_level)
|
|
{
|
|
struct btrfs_fs_info *fs_info = root->fs_info;
|
|
int ret = 0;
|
|
|
|
if ((p->search_for_split || ins_len > 0) && btrfs_header_nritems(b) >=
|
|
BTRFS_NODEPTRS_PER_BLOCK(fs_info) - 3) {
|
|
|
|
if (*write_lock_level < level + 1) {
|
|
*write_lock_level = level + 1;
|
|
btrfs_release_path(p);
|
|
return -EAGAIN;
|
|
}
|
|
|
|
reada_for_balance(p, level);
|
|
ret = split_node(trans, root, p, level);
|
|
|
|
b = p->nodes[level];
|
|
} else if (ins_len < 0 && btrfs_header_nritems(b) <
|
|
BTRFS_NODEPTRS_PER_BLOCK(fs_info) / 2) {
|
|
|
|
if (*write_lock_level < level + 1) {
|
|
*write_lock_level = level + 1;
|
|
btrfs_release_path(p);
|
|
return -EAGAIN;
|
|
}
|
|
|
|
reada_for_balance(p, level);
|
|
ret = balance_level(trans, root, p, level);
|
|
if (ret)
|
|
return ret;
|
|
|
|
b = p->nodes[level];
|
|
if (!b) {
|
|
btrfs_release_path(p);
|
|
return -EAGAIN;
|
|
}
|
|
BUG_ON(btrfs_header_nritems(b) == 1);
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
int btrfs_find_item(struct btrfs_root *fs_root, struct btrfs_path *path,
|
|
u64 iobjectid, u64 ioff, u8 key_type,
|
|
struct btrfs_key *found_key)
|
|
{
|
|
int ret;
|
|
struct btrfs_key key;
|
|
struct extent_buffer *eb;
|
|
|
|
ASSERT(path);
|
|
ASSERT(found_key);
|
|
|
|
key.type = key_type;
|
|
key.objectid = iobjectid;
|
|
key.offset = ioff;
|
|
|
|
ret = btrfs_search_slot(NULL, fs_root, &key, path, 0, 0);
|
|
if (ret < 0)
|
|
return ret;
|
|
|
|
eb = path->nodes[0];
|
|
if (ret && path->slots[0] >= btrfs_header_nritems(eb)) {
|
|
ret = btrfs_next_leaf(fs_root, path);
|
|
if (ret)
|
|
return ret;
|
|
eb = path->nodes[0];
|
|
}
|
|
|
|
btrfs_item_key_to_cpu(eb, found_key, path->slots[0]);
|
|
if (found_key->type != key.type ||
|
|
found_key->objectid != key.objectid)
|
|
return 1;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static struct extent_buffer *btrfs_search_slot_get_root(struct btrfs_root *root,
|
|
struct btrfs_path *p,
|
|
int write_lock_level)
|
|
{
|
|
struct extent_buffer *b;
|
|
int root_lock = 0;
|
|
int level = 0;
|
|
|
|
if (p->search_commit_root) {
|
|
b = root->commit_root;
|
|
atomic_inc(&b->refs);
|
|
level = btrfs_header_level(b);
|
|
/*
|
|
* Ensure that all callers have set skip_locking when
|
|
* p->search_commit_root = 1.
|
|
*/
|
|
ASSERT(p->skip_locking == 1);
|
|
|
|
goto out;
|
|
}
|
|
|
|
if (p->skip_locking) {
|
|
b = btrfs_root_node(root);
|
|
level = btrfs_header_level(b);
|
|
goto out;
|
|
}
|
|
|
|
/* We try very hard to do read locks on the root */
|
|
root_lock = BTRFS_READ_LOCK;
|
|
|
|
/*
|
|
* If the level is set to maximum, we can skip trying to get the read
|
|
* lock.
|
|
*/
|
|
if (write_lock_level < BTRFS_MAX_LEVEL) {
|
|
/*
|
|
* We don't know the level of the root node until we actually
|
|
* have it read locked
|
|
*/
|
|
if (p->nowait) {
|
|
b = btrfs_try_read_lock_root_node(root);
|
|
if (IS_ERR(b))
|
|
return b;
|
|
} else {
|
|
b = btrfs_read_lock_root_node(root);
|
|
}
|
|
level = btrfs_header_level(b);
|
|
if (level > write_lock_level)
|
|
goto out;
|
|
|
|
/* Whoops, must trade for write lock */
|
|
btrfs_tree_read_unlock(b);
|
|
free_extent_buffer(b);
|
|
}
|
|
|
|
b = btrfs_lock_root_node(root);
|
|
root_lock = BTRFS_WRITE_LOCK;
|
|
|
|
/* The level might have changed, check again */
|
|
level = btrfs_header_level(b);
|
|
|
|
out:
|
|
/*
|
|
* The root may have failed to write out at some point, and thus is no
|
|
* longer valid, return an error in this case.
|
|
*/
|
|
if (!extent_buffer_uptodate(b)) {
|
|
if (root_lock)
|
|
btrfs_tree_unlock_rw(b, root_lock);
|
|
free_extent_buffer(b);
|
|
return ERR_PTR(-EIO);
|
|
}
|
|
|
|
p->nodes[level] = b;
|
|
if (!p->skip_locking)
|
|
p->locks[level] = root_lock;
|
|
/*
|
|
* Callers are responsible for dropping b's references.
|
|
*/
|
|
return b;
|
|
}
|
|
|
|
/*
|
|
* Replace the extent buffer at the lowest level of the path with a cloned
|
|
* version. The purpose is to be able to use it safely, after releasing the
|
|
* commit root semaphore, even if relocation is happening in parallel, the
|
|
* transaction used for relocation is committed and the extent buffer is
|
|
* reallocated in the next transaction.
|
|
*
|
|
* This is used in a context where the caller does not prevent transaction
|
|
* commits from happening, either by holding a transaction handle or holding
|
|
* some lock, while it's doing searches through a commit root.
|
|
* At the moment it's only used for send operations.
|
|
*/
|
|
static int finish_need_commit_sem_search(struct btrfs_path *path)
|
|
{
|
|
const int i = path->lowest_level;
|
|
const int slot = path->slots[i];
|
|
struct extent_buffer *lowest = path->nodes[i];
|
|
struct extent_buffer *clone;
|
|
|
|
ASSERT(path->need_commit_sem);
|
|
|
|
if (!lowest)
|
|
return 0;
|
|
|
|
lockdep_assert_held_read(&lowest->fs_info->commit_root_sem);
|
|
|
|
clone = btrfs_clone_extent_buffer(lowest);
|
|
if (!clone)
|
|
return -ENOMEM;
|
|
|
|
btrfs_release_path(path);
|
|
path->nodes[i] = clone;
|
|
path->slots[i] = slot;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static inline int search_for_key_slot(struct extent_buffer *eb,
|
|
int search_low_slot,
|
|
const struct btrfs_key *key,
|
|
int prev_cmp,
|
|
int *slot)
|
|
{
|
|
/*
|
|
* If a previous call to btrfs_bin_search() on a parent node returned an
|
|
* exact match (prev_cmp == 0), we can safely assume the target key will
|
|
* always be at slot 0 on lower levels, since each key pointer
|
|
* (struct btrfs_key_ptr) refers to the lowest key accessible from the
|
|
* subtree it points to. Thus we can skip searching lower levels.
|
|
*/
|
|
if (prev_cmp == 0) {
|
|
*slot = 0;
|
|
return 0;
|
|
}
|
|
|
|
return btrfs_generic_bin_search(eb, search_low_slot, key, slot);
|
|
}
|
|
|
|
static int search_leaf(struct btrfs_trans_handle *trans,
|
|
struct btrfs_root *root,
|
|
const struct btrfs_key *key,
|
|
struct btrfs_path *path,
|
|
int ins_len,
|
|
int prev_cmp)
|
|
{
|
|
struct extent_buffer *leaf = path->nodes[0];
|
|
int leaf_free_space = -1;
|
|
int search_low_slot = 0;
|
|
int ret;
|
|
bool do_bin_search = true;
|
|
|
|
/*
|
|
* If we are doing an insertion, the leaf has enough free space and the
|
|
* destination slot for the key is not slot 0, then we can unlock our
|
|
* write lock on the parent, and any other upper nodes, before doing the
|
|
* binary search on the leaf (with search_for_key_slot()), allowing other
|
|
* tasks to lock the parent and any other upper nodes.
|
|
*/
|
|
if (ins_len > 0) {
|
|
/*
|
|
* Cache the leaf free space, since we will need it later and it
|
|
* will not change until then.
|
|
*/
|
|
leaf_free_space = btrfs_leaf_free_space(leaf);
|
|
|
|
/*
|
|
* !path->locks[1] means we have a single node tree, the leaf is
|
|
* the root of the tree.
|
|
*/
|
|
if (path->locks[1] && leaf_free_space >= ins_len) {
|
|
struct btrfs_disk_key first_key;
|
|
|
|
ASSERT(btrfs_header_nritems(leaf) > 0);
|
|
btrfs_item_key(leaf, &first_key, 0);
|
|
|
|
/*
|
|
* Doing the extra comparison with the first key is cheap,
|
|
* taking into account that the first key is very likely
|
|
* already in a cache line because it immediately follows
|
|
* the extent buffer's header and we have recently accessed
|
|
* the header's level field.
|
|
*/
|
|
ret = comp_keys(&first_key, key);
|
|
if (ret < 0) {
|
|
/*
|
|
* The first key is smaller than the key we want
|
|
* to insert, so we are safe to unlock all upper
|
|
* nodes and we have to do the binary search.
|
|
*
|
|
* We do use btrfs_unlock_up_safe() and not
|
|
* unlock_up() because the later does not unlock
|
|
* nodes with a slot of 0 - we can safely unlock
|
|
* any node even if its slot is 0 since in this
|
|
* case the key does not end up at slot 0 of the
|
|
* leaf and there's no need to split the leaf.
|
|
*/
|
|
btrfs_unlock_up_safe(path, 1);
|
|
search_low_slot = 1;
|
|
} else {
|
|
/*
|
|
* The first key is >= then the key we want to
|
|
* insert, so we can skip the binary search as
|
|
* the target key will be at slot 0.
|
|
*
|
|
* We can not unlock upper nodes when the key is
|
|
* less than the first key, because we will need
|
|
* to update the key at slot 0 of the parent node
|
|
* and possibly of other upper nodes too.
|
|
* If the key matches the first key, then we can
|
|
* unlock all the upper nodes, using
|
|
* btrfs_unlock_up_safe() instead of unlock_up()
|
|
* as stated above.
|
|
*/
|
|
if (ret == 0)
|
|
btrfs_unlock_up_safe(path, 1);
|
|
/*
|
|
* ret is already 0 or 1, matching the result of
|
|
* a btrfs_bin_search() call, so there is no need
|
|
* to adjust it.
|
|
*/
|
|
do_bin_search = false;
|
|
path->slots[0] = 0;
|
|
}
|
|
}
|
|
}
|
|
|
|
if (do_bin_search) {
|
|
ret = search_for_key_slot(leaf, search_low_slot, key,
|
|
prev_cmp, &path->slots[0]);
|
|
if (ret < 0)
|
|
return ret;
|
|
}
|
|
|
|
if (ins_len > 0) {
|
|
/*
|
|
* Item key already exists. In this case, if we are allowed to
|
|
* insert the item (for example, in dir_item case, item key
|
|
* collision is allowed), it will be merged with the original
|
|
* item. Only the item size grows, no new btrfs item will be
|
|
* added. If search_for_extension is not set, ins_len already
|
|
* accounts the size btrfs_item, deduct it here so leaf space
|
|
* check will be correct.
|
|
*/
|
|
if (ret == 0 && !path->search_for_extension) {
|
|
ASSERT(ins_len >= sizeof(struct btrfs_item));
|
|
ins_len -= sizeof(struct btrfs_item);
|
|
}
|
|
|
|
ASSERT(leaf_free_space >= 0);
|
|
|
|
if (leaf_free_space < ins_len) {
|
|
int err;
|
|
|
|
err = split_leaf(trans, root, key, path, ins_len,
|
|
(ret == 0));
|
|
ASSERT(err <= 0);
|
|
if (WARN_ON(err > 0))
|
|
err = -EUCLEAN;
|
|
if (err)
|
|
ret = err;
|
|
}
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* btrfs_search_slot - look for a key in a tree and perform necessary
|
|
* modifications to preserve tree invariants.
|
|
*
|
|
* @trans: Handle of transaction, used when modifying the tree
|
|
* @p: Holds all btree nodes along the search path
|
|
* @root: The root node of the tree
|
|
* @key: The key we are looking for
|
|
* @ins_len: Indicates purpose of search:
|
|
* >0 for inserts it's size of item inserted (*)
|
|
* <0 for deletions
|
|
* 0 for plain searches, not modifying the tree
|
|
*
|
|
* (*) If size of item inserted doesn't include
|
|
* sizeof(struct btrfs_item), then p->search_for_extension must
|
|
* be set.
|
|
* @cow: boolean should CoW operations be performed. Must always be 1
|
|
* when modifying the tree.
|
|
*
|
|
* If @ins_len > 0, nodes and leaves will be split as we walk down the tree.
|
|
* If @ins_len < 0, nodes will be merged as we walk down the tree (if possible)
|
|
*
|
|
* If @key is found, 0 is returned and you can find the item in the leaf level
|
|
* of the path (level 0)
|
|
*
|
|
* If @key isn't found, 1 is returned and the leaf level of the path (level 0)
|
|
* points to the slot where it should be inserted
|
|
*
|
|
* If an error is encountered while searching the tree a negative error number
|
|
* is returned
|
|
*/
|
|
int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root *root,
|
|
const struct btrfs_key *key, struct btrfs_path *p,
|
|
int ins_len, int cow)
|
|
{
|
|
struct btrfs_fs_info *fs_info = root->fs_info;
|
|
struct extent_buffer *b;
|
|
int slot;
|
|
int ret;
|
|
int err;
|
|
int level;
|
|
int lowest_unlock = 1;
|
|
/* everything at write_lock_level or lower must be write locked */
|
|
int write_lock_level = 0;
|
|
u8 lowest_level = 0;
|
|
int min_write_lock_level;
|
|
int prev_cmp;
|
|
|
|
might_sleep();
|
|
|
|
lowest_level = p->lowest_level;
|
|
WARN_ON(lowest_level && ins_len > 0);
|
|
WARN_ON(p->nodes[0] != NULL);
|
|
BUG_ON(!cow && ins_len);
|
|
|
|
/*
|
|
* For now only allow nowait for read only operations. There's no
|
|
* strict reason why we can't, we just only need it for reads so it's
|
|
* only implemented for reads.
|
|
*/
|
|
ASSERT(!p->nowait || !cow);
|
|
|
|
if (ins_len < 0) {
|
|
lowest_unlock = 2;
|
|
|
|
/* when we are removing items, we might have to go up to level
|
|
* two as we update tree pointers Make sure we keep write
|
|
* for those levels as well
|
|
*/
|
|
write_lock_level = 2;
|
|
} else if (ins_len > 0) {
|
|
/*
|
|
* for inserting items, make sure we have a write lock on
|
|
* level 1 so we can update keys
|
|
*/
|
|
write_lock_level = 1;
|
|
}
|
|
|
|
if (!cow)
|
|
write_lock_level = -1;
|
|
|
|
if (cow && (p->keep_locks || p->lowest_level))
|
|
write_lock_level = BTRFS_MAX_LEVEL;
|
|
|
|
min_write_lock_level = write_lock_level;
|
|
|
|
if (p->need_commit_sem) {
|
|
ASSERT(p->search_commit_root);
|
|
if (p->nowait) {
|
|
if (!down_read_trylock(&fs_info->commit_root_sem))
|
|
return -EAGAIN;
|
|
} else {
|
|
down_read(&fs_info->commit_root_sem);
|
|
}
|
|
}
|
|
|
|
again:
|
|
prev_cmp = -1;
|
|
b = btrfs_search_slot_get_root(root, p, write_lock_level);
|
|
if (IS_ERR(b)) {
|
|
ret = PTR_ERR(b);
|
|
goto done;
|
|
}
|
|
|
|
while (b) {
|
|
int dec = 0;
|
|
|
|
level = btrfs_header_level(b);
|
|
|
|
if (cow) {
|
|
bool last_level = (level == (BTRFS_MAX_LEVEL - 1));
|
|
|
|
/*
|
|
* if we don't really need to cow this block
|
|
* then we don't want to set the path blocking,
|
|
* so we test it here
|
|
*/
|
|
if (!should_cow_block(trans, root, b))
|
|
goto cow_done;
|
|
|
|
/*
|
|
* must have write locks on this node and the
|
|
* parent
|
|
*/
|
|
if (level > write_lock_level ||
|
|
(level + 1 > write_lock_level &&
|
|
level + 1 < BTRFS_MAX_LEVEL &&
|
|
p->nodes[level + 1])) {
|
|
write_lock_level = level + 1;
|
|
btrfs_release_path(p);
|
|
goto again;
|
|
}
|
|
|
|
if (last_level)
|
|
err = btrfs_cow_block(trans, root, b, NULL, 0,
|
|
&b,
|
|
BTRFS_NESTING_COW);
|
|
else
|
|
err = btrfs_cow_block(trans, root, b,
|
|
p->nodes[level + 1],
|
|
p->slots[level + 1], &b,
|
|
BTRFS_NESTING_COW);
|
|
if (err) {
|
|
ret = err;
|
|
goto done;
|
|
}
|
|
}
|
|
cow_done:
|
|
p->nodes[level] = b;
|
|
|
|
/*
|
|
* we have a lock on b and as long as we aren't changing
|
|
* the tree, there is no way to for the items in b to change.
|
|
* It is safe to drop the lock on our parent before we
|
|
* go through the expensive btree search on b.
|
|
*
|
|
* If we're inserting or deleting (ins_len != 0), then we might
|
|
* be changing slot zero, which may require changing the parent.
|
|
* So, we can't drop the lock until after we know which slot
|
|
* we're operating on.
|
|
*/
|
|
if (!ins_len && !p->keep_locks) {
|
|
int u = level + 1;
|
|
|
|
if (u < BTRFS_MAX_LEVEL && p->locks[u]) {
|
|
btrfs_tree_unlock_rw(p->nodes[u], p->locks[u]);
|
|
p->locks[u] = 0;
|
|
}
|
|
}
|
|
|
|
if (level == 0) {
|
|
if (ins_len > 0)
|
|
ASSERT(write_lock_level >= 1);
|
|
|
|
ret = search_leaf(trans, root, key, p, ins_len, prev_cmp);
|
|
if (!p->search_for_split)
|
|
unlock_up(p, level, lowest_unlock,
|
|
min_write_lock_level, NULL);
|
|
goto done;
|
|
}
|
|
|
|
ret = search_for_key_slot(b, 0, key, prev_cmp, &slot);
|
|
if (ret < 0)
|
|
goto done;
|
|
prev_cmp = ret;
|
|
|
|
if (ret && slot > 0) {
|
|
dec = 1;
|
|
slot--;
|
|
}
|
|
p->slots[level] = slot;
|
|
err = setup_nodes_for_search(trans, root, p, b, level, ins_len,
|
|
&write_lock_level);
|
|
if (err == -EAGAIN)
|
|
goto again;
|
|
if (err) {
|
|
ret = err;
|
|
goto done;
|
|
}
|
|
b = p->nodes[level];
|
|
slot = p->slots[level];
|
|
|
|
/*
|
|
* Slot 0 is special, if we change the key we have to update
|
|
* the parent pointer which means we must have a write lock on
|
|
* the parent
|
|
*/
|
|
if (slot == 0 && ins_len && write_lock_level < level + 1) {
|
|
write_lock_level = level + 1;
|
|
btrfs_release_path(p);
|
|
goto again;
|
|
}
|
|
|
|
unlock_up(p, level, lowest_unlock, min_write_lock_level,
|
|
&write_lock_level);
|
|
|
|
if (level == lowest_level) {
|
|
if (dec)
|
|
p->slots[level]++;
|
|
goto done;
|
|
}
|
|
|
|
err = read_block_for_search(root, p, &b, level, slot, key);
|
|
if (err == -EAGAIN)
|
|
goto again;
|
|
if (err) {
|
|
ret = err;
|
|
goto done;
|
|
}
|
|
|
|
if (!p->skip_locking) {
|
|
level = btrfs_header_level(b);
|
|
|
|
btrfs_maybe_reset_lockdep_class(root, b);
|
|
|
|
if (level <= write_lock_level) {
|
|
btrfs_tree_lock(b);
|
|
p->locks[level] = BTRFS_WRITE_LOCK;
|
|
} else {
|
|
if (p->nowait) {
|
|
if (!btrfs_try_tree_read_lock(b)) {
|
|
free_extent_buffer(b);
|
|
ret = -EAGAIN;
|
|
goto done;
|
|
}
|
|
} else {
|
|
btrfs_tree_read_lock(b);
|
|
}
|
|
p->locks[level] = BTRFS_READ_LOCK;
|
|
}
|
|
p->nodes[level] = b;
|
|
}
|
|
}
|
|
ret = 1;
|
|
done:
|
|
if (ret < 0 && !p->skip_release_on_error)
|
|
btrfs_release_path(p);
|
|
|
|
if (p->need_commit_sem) {
|
|
int ret2;
|
|
|
|
ret2 = finish_need_commit_sem_search(p);
|
|
up_read(&fs_info->commit_root_sem);
|
|
if (ret2)
|
|
ret = ret2;
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
ALLOW_ERROR_INJECTION(btrfs_search_slot, ERRNO);
|
|
|
|
/*
|
|
* Like btrfs_search_slot, this looks for a key in the given tree. It uses the
|
|
* current state of the tree together with the operations recorded in the tree
|
|
* modification log to search for the key in a previous version of this tree, as
|
|
* denoted by the time_seq parameter.
|
|
*
|
|
* Naturally, there is no support for insert, delete or cow operations.
|
|
*
|
|
* The resulting path and return value will be set up as if we called
|
|
* btrfs_search_slot at that point in time with ins_len and cow both set to 0.
|
|
*/
|
|
int btrfs_search_old_slot(struct btrfs_root *root, const struct btrfs_key *key,
|
|
struct btrfs_path *p, u64 time_seq)
|
|
{
|
|
struct btrfs_fs_info *fs_info = root->fs_info;
|
|
struct extent_buffer *b;
|
|
int slot;
|
|
int ret;
|
|
int err;
|
|
int level;
|
|
int lowest_unlock = 1;
|
|
u8 lowest_level = 0;
|
|
|
|
lowest_level = p->lowest_level;
|
|
WARN_ON(p->nodes[0] != NULL);
|
|
ASSERT(!p->nowait);
|
|
|
|
if (p->search_commit_root) {
|
|
BUG_ON(time_seq);
|
|
return btrfs_search_slot(NULL, root, key, p, 0, 0);
|
|
}
|
|
|
|
again:
|
|
b = btrfs_get_old_root(root, time_seq);
|
|
if (!b) {
|
|
ret = -EIO;
|
|
goto done;
|
|
}
|
|
level = btrfs_header_level(b);
|
|
p->locks[level] = BTRFS_READ_LOCK;
|
|
|
|
while (b) {
|
|
int dec = 0;
|
|
|
|
level = btrfs_header_level(b);
|
|
p->nodes[level] = b;
|
|
|
|
/*
|
|
* we have a lock on b and as long as we aren't changing
|
|
* the tree, there is no way to for the items in b to change.
|
|
* It is safe to drop the lock on our parent before we
|
|
* go through the expensive btree search on b.
|
|
*/
|
|
btrfs_unlock_up_safe(p, level + 1);
|
|
|
|
ret = btrfs_bin_search(b, key, &slot);
|
|
if (ret < 0)
|
|
goto done;
|
|
|
|
if (level == 0) {
|
|
p->slots[level] = slot;
|
|
unlock_up(p, level, lowest_unlock, 0, NULL);
|
|
goto done;
|
|
}
|
|
|
|
if (ret && slot > 0) {
|
|
dec = 1;
|
|
slot--;
|
|
}
|
|
p->slots[level] = slot;
|
|
unlock_up(p, level, lowest_unlock, 0, NULL);
|
|
|
|
if (level == lowest_level) {
|
|
if (dec)
|
|
p->slots[level]++;
|
|
goto done;
|
|
}
|
|
|
|
err = read_block_for_search(root, p, &b, level, slot, key);
|
|
if (err == -EAGAIN)
|
|
goto again;
|
|
if (err) {
|
|
ret = err;
|
|
goto done;
|
|
}
|
|
|
|
level = btrfs_header_level(b);
|
|
btrfs_tree_read_lock(b);
|
|
b = btrfs_tree_mod_log_rewind(fs_info, p, b, time_seq);
|
|
if (!b) {
|
|
ret = -ENOMEM;
|
|
goto done;
|
|
}
|
|
p->locks[level] = BTRFS_READ_LOCK;
|
|
p->nodes[level] = b;
|
|
}
|
|
ret = 1;
|
|
done:
|
|
if (ret < 0)
|
|
btrfs_release_path(p);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* helper to use instead of search slot if no exact match is needed but
|
|
* instead the next or previous item should be returned.
|
|
* When find_higher is true, the next higher item is returned, the next lower
|
|
* otherwise.
|
|
* When return_any and find_higher are both true, and no higher item is found,
|
|
* return the next lower instead.
|
|
* When return_any is true and find_higher is false, and no lower item is found,
|
|
* return the next higher instead.
|
|
* It returns 0 if any item is found, 1 if none is found (tree empty), and
|
|
* < 0 on error
|
|
*/
|
|
int btrfs_search_slot_for_read(struct btrfs_root *root,
|
|
const struct btrfs_key *key,
|
|
struct btrfs_path *p, int find_higher,
|
|
int return_any)
|
|
{
|
|
int ret;
|
|
struct extent_buffer *leaf;
|
|
|
|
again:
|
|
ret = btrfs_search_slot(NULL, root, key, p, 0, 0);
|
|
if (ret <= 0)
|
|
return ret;
|
|
/*
|
|
* a return value of 1 means the path is at the position where the
|
|
* item should be inserted. Normally this is the next bigger item,
|
|
* but in case the previous item is the last in a leaf, path points
|
|
* to the first free slot in the previous leaf, i.e. at an invalid
|
|
* item.
|
|
*/
|
|
leaf = p->nodes[0];
|
|
|
|
if (find_higher) {
|
|
if (p->slots[0] >= btrfs_header_nritems(leaf)) {
|
|
ret = btrfs_next_leaf(root, p);
|
|
if (ret <= 0)
|
|
return ret;
|
|
if (!return_any)
|
|
return 1;
|
|
/*
|
|
* no higher item found, return the next
|
|
* lower instead
|
|
*/
|
|
return_any = 0;
|
|
find_higher = 0;
|
|
btrfs_release_path(p);
|
|
goto again;
|
|
}
|
|
} else {
|
|
if (p->slots[0] == 0) {
|
|
ret = btrfs_prev_leaf(root, p);
|
|
if (ret < 0)
|
|
return ret;
|
|
if (!ret) {
|
|
leaf = p->nodes[0];
|
|
if (p->slots[0] == btrfs_header_nritems(leaf))
|
|
p->slots[0]--;
|
|
return 0;
|
|
}
|
|
if (!return_any)
|
|
return 1;
|
|
/*
|
|
* no lower item found, return the next
|
|
* higher instead
|
|
*/
|
|
return_any = 0;
|
|
find_higher = 1;
|
|
btrfs_release_path(p);
|
|
goto again;
|
|
} else {
|
|
--p->slots[0];
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Execute search and call btrfs_previous_item to traverse backwards if the item
|
|
* was not found.
|
|
*
|
|
* Return 0 if found, 1 if not found and < 0 if error.
|
|
*/
|
|
int btrfs_search_backwards(struct btrfs_root *root, struct btrfs_key *key,
|
|
struct btrfs_path *path)
|
|
{
|
|
int ret;
|
|
|
|
ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
|
|
if (ret > 0)
|
|
ret = btrfs_previous_item(root, path, key->objectid, key->type);
|
|
|
|
if (ret == 0)
|
|
btrfs_item_key_to_cpu(path->nodes[0], key, path->slots[0]);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* Search for a valid slot for the given path.
|
|
*
|
|
* @root: The root node of the tree.
|
|
* @key: Will contain a valid item if found.
|
|
* @path: The starting point to validate the slot.
|
|
*
|
|
* Return: 0 if the item is valid
|
|
* 1 if not found
|
|
* <0 if error.
|
|
*/
|
|
int btrfs_get_next_valid_item(struct btrfs_root *root, struct btrfs_key *key,
|
|
struct btrfs_path *path)
|
|
{
|
|
while (1) {
|
|
int ret;
|
|
const int slot = path->slots[0];
|
|
const struct extent_buffer *leaf = path->nodes[0];
|
|
|
|
/* This is where we start walking the path. */
|
|
if (slot >= btrfs_header_nritems(leaf)) {
|
|
/*
|
|
* If we've reached the last slot in this leaf we need
|
|
* to go to the next leaf and reset the path.
|
|
*/
|
|
ret = btrfs_next_leaf(root, path);
|
|
if (ret)
|
|
return ret;
|
|
continue;
|
|
}
|
|
/* Store the found, valid item in @key. */
|
|
btrfs_item_key_to_cpu(leaf, key, slot);
|
|
break;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* adjust the pointers going up the tree, starting at level
|
|
* making sure the right key of each node is points to 'key'.
|
|
* This is used after shifting pointers to the left, so it stops
|
|
* fixing up pointers when a given leaf/node is not in slot 0 of the
|
|
* higher levels
|
|
*
|
|
*/
|
|
static void fixup_low_keys(struct btrfs_path *path,
|
|
struct btrfs_disk_key *key, int level)
|
|
{
|
|
int i;
|
|
struct extent_buffer *t;
|
|
int ret;
|
|
|
|
for (i = level; i < BTRFS_MAX_LEVEL; i++) {
|
|
int tslot = path->slots[i];
|
|
|
|
if (!path->nodes[i])
|
|
break;
|
|
t = path->nodes[i];
|
|
ret = btrfs_tree_mod_log_insert_key(t, tslot,
|
|
BTRFS_MOD_LOG_KEY_REPLACE);
|
|
BUG_ON(ret < 0);
|
|
btrfs_set_node_key(t, key, tslot);
|
|
btrfs_mark_buffer_dirty(path->nodes[i]);
|
|
if (tslot != 0)
|
|
break;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* update item key.
|
|
*
|
|
* This function isn't completely safe. It's the caller's responsibility
|
|
* that the new key won't break the order
|
|
*/
|
|
void btrfs_set_item_key_safe(struct btrfs_fs_info *fs_info,
|
|
struct btrfs_path *path,
|
|
const struct btrfs_key *new_key)
|
|
{
|
|
struct btrfs_disk_key disk_key;
|
|
struct extent_buffer *eb;
|
|
int slot;
|
|
|
|
eb = path->nodes[0];
|
|
slot = path->slots[0];
|
|
if (slot > 0) {
|
|
btrfs_item_key(eb, &disk_key, slot - 1);
|
|
if (unlikely(comp_keys(&disk_key, new_key) >= 0)) {
|
|
btrfs_crit(fs_info,
|
|
"slot %u key (%llu %u %llu) new key (%llu %u %llu)",
|
|
slot, btrfs_disk_key_objectid(&disk_key),
|
|
btrfs_disk_key_type(&disk_key),
|
|
btrfs_disk_key_offset(&disk_key),
|
|
new_key->objectid, new_key->type,
|
|
new_key->offset);
|
|
btrfs_print_leaf(eb);
|
|
BUG();
|
|
}
|
|
}
|
|
if (slot < btrfs_header_nritems(eb) - 1) {
|
|
btrfs_item_key(eb, &disk_key, slot + 1);
|
|
if (unlikely(comp_keys(&disk_key, new_key) <= 0)) {
|
|
btrfs_crit(fs_info,
|
|
"slot %u key (%llu %u %llu) new key (%llu %u %llu)",
|
|
slot, btrfs_disk_key_objectid(&disk_key),
|
|
btrfs_disk_key_type(&disk_key),
|
|
btrfs_disk_key_offset(&disk_key),
|
|
new_key->objectid, new_key->type,
|
|
new_key->offset);
|
|
btrfs_print_leaf(eb);
|
|
BUG();
|
|
}
|
|
}
|
|
|
|
btrfs_cpu_key_to_disk(&disk_key, new_key);
|
|
btrfs_set_item_key(eb, &disk_key, slot);
|
|
btrfs_mark_buffer_dirty(eb);
|
|
if (slot == 0)
|
|
fixup_low_keys(path, &disk_key, 1);
|
|
}
|
|
|
|
/*
|
|
* Check key order of two sibling extent buffers.
|
|
*
|
|
* Return true if something is wrong.
|
|
* Return false if everything is fine.
|
|
*
|
|
* Tree-checker only works inside one tree block, thus the following
|
|
* corruption can not be detected by tree-checker:
|
|
*
|
|
* Leaf @left | Leaf @right
|
|
* --------------------------------------------------------------
|
|
* | 1 | 2 | 3 | 4 | 5 | f6 | | 7 | 8 |
|
|
*
|
|
* Key f6 in leaf @left itself is valid, but not valid when the next
|
|
* key in leaf @right is 7.
|
|
* This can only be checked at tree block merge time.
|
|
* And since tree checker has ensured all key order in each tree block
|
|
* is correct, we only need to bother the last key of @left and the first
|
|
* key of @right.
|
|
*/
|
|
static bool check_sibling_keys(struct extent_buffer *left,
|
|
struct extent_buffer *right)
|
|
{
|
|
struct btrfs_key left_last;
|
|
struct btrfs_key right_first;
|
|
int level = btrfs_header_level(left);
|
|
int nr_left = btrfs_header_nritems(left);
|
|
int nr_right = btrfs_header_nritems(right);
|
|
|
|
/* No key to check in one of the tree blocks */
|
|
if (!nr_left || !nr_right)
|
|
return false;
|
|
|
|
if (level) {
|
|
btrfs_node_key_to_cpu(left, &left_last, nr_left - 1);
|
|
btrfs_node_key_to_cpu(right, &right_first, 0);
|
|
} else {
|
|
btrfs_item_key_to_cpu(left, &left_last, nr_left - 1);
|
|
btrfs_item_key_to_cpu(right, &right_first, 0);
|
|
}
|
|
|
|
if (btrfs_comp_cpu_keys(&left_last, &right_first) >= 0) {
|
|
btrfs_crit(left->fs_info,
|
|
"bad key order, sibling blocks, left last (%llu %u %llu) right first (%llu %u %llu)",
|
|
left_last.objectid, left_last.type,
|
|
left_last.offset, right_first.objectid,
|
|
right_first.type, right_first.offset);
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
/*
|
|
* try to push data from one node into the next node left in the
|
|
* tree.
|
|
*
|
|
* returns 0 if some ptrs were pushed left, < 0 if there was some horrible
|
|
* error, and > 0 if there was no room in the left hand block.
|
|
*/
|
|
static int push_node_left(struct btrfs_trans_handle *trans,
|
|
struct extent_buffer *dst,
|
|
struct extent_buffer *src, int empty)
|
|
{
|
|
struct btrfs_fs_info *fs_info = trans->fs_info;
|
|
int push_items = 0;
|
|
int src_nritems;
|
|
int dst_nritems;
|
|
int ret = 0;
|
|
|
|
src_nritems = btrfs_header_nritems(src);
|
|
dst_nritems = btrfs_header_nritems(dst);
|
|
push_items = BTRFS_NODEPTRS_PER_BLOCK(fs_info) - dst_nritems;
|
|
WARN_ON(btrfs_header_generation(src) != trans->transid);
|
|
WARN_ON(btrfs_header_generation(dst) != trans->transid);
|
|
|
|
if (!empty && src_nritems <= 8)
|
|
return 1;
|
|
|
|
if (push_items <= 0)
|
|
return 1;
|
|
|
|
if (empty) {
|
|
push_items = min(src_nritems, push_items);
|
|
if (push_items < src_nritems) {
|
|
/* leave at least 8 pointers in the node if
|
|
* we aren't going to empty it
|
|
*/
|
|
if (src_nritems - push_items < 8) {
|
|
if (push_items <= 8)
|
|
return 1;
|
|
push_items -= 8;
|
|
}
|
|
}
|
|
} else
|
|
push_items = min(src_nritems - 8, push_items);
|
|
|
|
/* dst is the left eb, src is the middle eb */
|
|
if (check_sibling_keys(dst, src)) {
|
|
ret = -EUCLEAN;
|
|
btrfs_abort_transaction(trans, ret);
|
|
return ret;
|
|
}
|
|
ret = btrfs_tree_mod_log_eb_copy(dst, src, dst_nritems, 0, push_items);
|
|
if (ret) {
|
|
btrfs_abort_transaction(trans, ret);
|
|
return ret;
|
|
}
|
|
copy_extent_buffer(dst, src,
|
|
btrfs_node_key_ptr_offset(dst, dst_nritems),
|
|
btrfs_node_key_ptr_offset(src, 0),
|
|
push_items * sizeof(struct btrfs_key_ptr));
|
|
|
|
if (push_items < src_nritems) {
|
|
/*
|
|
* Don't call btrfs_tree_mod_log_insert_move() here, key removal
|
|
* was already fully logged by btrfs_tree_mod_log_eb_copy() above.
|
|
*/
|
|
memmove_extent_buffer(src, btrfs_node_key_ptr_offset(src, 0),
|
|
btrfs_node_key_ptr_offset(src, push_items),
|
|
(src_nritems - push_items) *
|
|
sizeof(struct btrfs_key_ptr));
|
|
}
|
|
btrfs_set_header_nritems(src, src_nritems - push_items);
|
|
btrfs_set_header_nritems(dst, dst_nritems + push_items);
|
|
btrfs_mark_buffer_dirty(src);
|
|
btrfs_mark_buffer_dirty(dst);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* try to push data from one node into the next node right in the
|
|
* tree.
|
|
*
|
|
* returns 0 if some ptrs were pushed, < 0 if there was some horrible
|
|
* error, and > 0 if there was no room in the right hand block.
|
|
*
|
|
* this will only push up to 1/2 the contents of the left node over
|
|
*/
|
|
static int balance_node_right(struct btrfs_trans_handle *trans,
|
|
struct extent_buffer *dst,
|
|
struct extent_buffer *src)
|
|
{
|
|
struct btrfs_fs_info *fs_info = trans->fs_info;
|
|
int push_items = 0;
|
|
int max_push;
|
|
int src_nritems;
|
|
int dst_nritems;
|
|
int ret = 0;
|
|
|
|
WARN_ON(btrfs_header_generation(src) != trans->transid);
|
|
WARN_ON(btrfs_header_generation(dst) != trans->transid);
|
|
|
|
src_nritems = btrfs_header_nritems(src);
|
|
dst_nritems = btrfs_header_nritems(dst);
|
|
push_items = BTRFS_NODEPTRS_PER_BLOCK(fs_info) - dst_nritems;
|
|
if (push_items <= 0)
|
|
return 1;
|
|
|
|
if (src_nritems < 4)
|
|
return 1;
|
|
|
|
max_push = src_nritems / 2 + 1;
|
|
/* don't try to empty the node */
|
|
if (max_push >= src_nritems)
|
|
return 1;
|
|
|
|
if (max_push < push_items)
|
|
push_items = max_push;
|
|
|
|
/* dst is the right eb, src is the middle eb */
|
|
if (check_sibling_keys(src, dst)) {
|
|
ret = -EUCLEAN;
|
|
btrfs_abort_transaction(trans, ret);
|
|
return ret;
|
|
}
|
|
ret = btrfs_tree_mod_log_insert_move(dst, push_items, 0, dst_nritems);
|
|
BUG_ON(ret < 0);
|
|
memmove_extent_buffer(dst, btrfs_node_key_ptr_offset(dst, push_items),
|
|
btrfs_node_key_ptr_offset(dst, 0),
|
|
(dst_nritems) *
|
|
sizeof(struct btrfs_key_ptr));
|
|
|
|
ret = btrfs_tree_mod_log_eb_copy(dst, src, 0, src_nritems - push_items,
|
|
push_items);
|
|
if (ret) {
|
|
btrfs_abort_transaction(trans, ret);
|
|
return ret;
|
|
}
|
|
copy_extent_buffer(dst, src,
|
|
btrfs_node_key_ptr_offset(dst, 0),
|
|
btrfs_node_key_ptr_offset(src, src_nritems - push_items),
|
|
push_items * sizeof(struct btrfs_key_ptr));
|
|
|
|
btrfs_set_header_nritems(src, src_nritems - push_items);
|
|
btrfs_set_header_nritems(dst, dst_nritems + push_items);
|
|
|
|
btrfs_mark_buffer_dirty(src);
|
|
btrfs_mark_buffer_dirty(dst);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* helper function to insert a new root level in the tree.
|
|
* A new node is allocated, and a single item is inserted to
|
|
* point to the existing root
|
|
*
|
|
* returns zero on success or < 0 on failure.
|
|
*/
|
|
static noinline int insert_new_root(struct btrfs_trans_handle *trans,
|
|
struct btrfs_root *root,
|
|
struct btrfs_path *path, int level)
|
|
{
|
|
struct btrfs_fs_info *fs_info = root->fs_info;
|
|
u64 lower_gen;
|
|
struct extent_buffer *lower;
|
|
struct extent_buffer *c;
|
|
struct extent_buffer *old;
|
|
struct btrfs_disk_key lower_key;
|
|
int ret;
|
|
|
|
BUG_ON(path->nodes[level]);
|
|
BUG_ON(path->nodes[level-1] != root->node);
|
|
|
|
lower = path->nodes[level-1];
|
|
if (level == 1)
|
|
btrfs_item_key(lower, &lower_key, 0);
|
|
else
|
|
btrfs_node_key(lower, &lower_key, 0);
|
|
|
|
c = btrfs_alloc_tree_block(trans, root, 0, root->root_key.objectid,
|
|
&lower_key, level, root->node->start, 0,
|
|
BTRFS_NESTING_NEW_ROOT);
|
|
if (IS_ERR(c))
|
|
return PTR_ERR(c);
|
|
|
|
root_add_used(root, fs_info->nodesize);
|
|
|
|
btrfs_set_header_nritems(c, 1);
|
|
btrfs_set_node_key(c, &lower_key, 0);
|
|
btrfs_set_node_blockptr(c, 0, lower->start);
|
|
lower_gen = btrfs_header_generation(lower);
|
|
WARN_ON(lower_gen != trans->transid);
|
|
|
|
btrfs_set_node_ptr_generation(c, 0, lower_gen);
|
|
|
|
btrfs_mark_buffer_dirty(c);
|
|
|
|
old = root->node;
|
|
ret = btrfs_tree_mod_log_insert_root(root->node, c, false);
|
|
BUG_ON(ret < 0);
|
|
rcu_assign_pointer(root->node, c);
|
|
|
|
/* the super has an extra ref to root->node */
|
|
free_extent_buffer(old);
|
|
|
|
add_root_to_dirty_list(root);
|
|
atomic_inc(&c->refs);
|
|
path->nodes[level] = c;
|
|
path->locks[level] = BTRFS_WRITE_LOCK;
|
|
path->slots[level] = 0;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* worker function to insert a single pointer in a node.
|
|
* the node should have enough room for the pointer already
|
|
*
|
|
* slot and level indicate where you want the key to go, and
|
|
* blocknr is the block the key points to.
|
|
*/
|
|
static void insert_ptr(struct btrfs_trans_handle *trans,
|
|
struct btrfs_path *path,
|
|
struct btrfs_disk_key *key, u64 bytenr,
|
|
int slot, int level)
|
|
{
|
|
struct extent_buffer *lower;
|
|
int nritems;
|
|
int ret;
|
|
|
|
BUG_ON(!path->nodes[level]);
|
|
btrfs_assert_tree_write_locked(path->nodes[level]);
|
|
lower = path->nodes[level];
|
|
nritems = btrfs_header_nritems(lower);
|
|
BUG_ON(slot > nritems);
|
|
BUG_ON(nritems == BTRFS_NODEPTRS_PER_BLOCK(trans->fs_info));
|
|
if (slot != nritems) {
|
|
if (level) {
|
|
ret = btrfs_tree_mod_log_insert_move(lower, slot + 1,
|
|
slot, nritems - slot);
|
|
BUG_ON(ret < 0);
|
|
}
|
|
memmove_extent_buffer(lower,
|
|
btrfs_node_key_ptr_offset(lower, slot + 1),
|
|
btrfs_node_key_ptr_offset(lower, slot),
|
|
(nritems - slot) * sizeof(struct btrfs_key_ptr));
|
|
}
|
|
if (level) {
|
|
ret = btrfs_tree_mod_log_insert_key(lower, slot,
|
|
BTRFS_MOD_LOG_KEY_ADD);
|
|
BUG_ON(ret < 0);
|
|
}
|
|
btrfs_set_node_key(lower, key, slot);
|
|
btrfs_set_node_blockptr(lower, slot, bytenr);
|
|
WARN_ON(trans->transid == 0);
|
|
btrfs_set_node_ptr_generation(lower, slot, trans->transid);
|
|
btrfs_set_header_nritems(lower, nritems + 1);
|
|
btrfs_mark_buffer_dirty(lower);
|
|
}
|
|
|
|
/*
|
|
* split the node at the specified level in path in two.
|
|
* The path is corrected to point to the appropriate node after the split
|
|
*
|
|
* Before splitting this tries to make some room in the node by pushing
|
|
* left and right, if either one works, it returns right away.
|
|
*
|
|
* returns 0 on success and < 0 on failure
|
|
*/
|
|
static noinline int split_node(struct btrfs_trans_handle *trans,
|
|
struct btrfs_root *root,
|
|
struct btrfs_path *path, int level)
|
|
{
|
|
struct btrfs_fs_info *fs_info = root->fs_info;
|
|
struct extent_buffer *c;
|
|
struct extent_buffer *split;
|
|
struct btrfs_disk_key disk_key;
|
|
int mid;
|
|
int ret;
|
|
u32 c_nritems;
|
|
|
|
c = path->nodes[level];
|
|
WARN_ON(btrfs_header_generation(c) != trans->transid);
|
|
if (c == root->node) {
|
|
/*
|
|
* trying to split the root, lets make a new one
|
|
*
|
|
* tree mod log: We don't log_removal old root in
|
|
* insert_new_root, because that root buffer will be kept as a
|
|
* normal node. We are going to log removal of half of the
|
|
* elements below with btrfs_tree_mod_log_eb_copy(). We're
|
|
* holding a tree lock on the buffer, which is why we cannot
|
|
* race with other tree_mod_log users.
|
|
*/
|
|
ret = insert_new_root(trans, root, path, level + 1);
|
|
if (ret)
|
|
return ret;
|
|
} else {
|
|
ret = push_nodes_for_insert(trans, root, path, level);
|
|
c = path->nodes[level];
|
|
if (!ret && btrfs_header_nritems(c) <
|
|
BTRFS_NODEPTRS_PER_BLOCK(fs_info) - 3)
|
|
return 0;
|
|
if (ret < 0)
|
|
return ret;
|
|
}
|
|
|
|
c_nritems = btrfs_header_nritems(c);
|
|
mid = (c_nritems + 1) / 2;
|
|
btrfs_node_key(c, &disk_key, mid);
|
|
|
|
split = btrfs_alloc_tree_block(trans, root, 0, root->root_key.objectid,
|
|
&disk_key, level, c->start, 0,
|
|
BTRFS_NESTING_SPLIT);
|
|
if (IS_ERR(split))
|
|
return PTR_ERR(split);
|
|
|
|
root_add_used(root, fs_info->nodesize);
|
|
ASSERT(btrfs_header_level(c) == level);
|
|
|
|
ret = btrfs_tree_mod_log_eb_copy(split, c, 0, mid, c_nritems - mid);
|
|
if (ret) {
|
|
btrfs_abort_transaction(trans, ret);
|
|
return ret;
|
|
}
|
|
copy_extent_buffer(split, c,
|
|
btrfs_node_key_ptr_offset(split, 0),
|
|
btrfs_node_key_ptr_offset(c, mid),
|
|
(c_nritems - mid) * sizeof(struct btrfs_key_ptr));
|
|
btrfs_set_header_nritems(split, c_nritems - mid);
|
|
btrfs_set_header_nritems(c, mid);
|
|
|
|
btrfs_mark_buffer_dirty(c);
|
|
btrfs_mark_buffer_dirty(split);
|
|
|
|
insert_ptr(trans, path, &disk_key, split->start,
|
|
path->slots[level + 1] + 1, level + 1);
|
|
|
|
if (path->slots[level] >= mid) {
|
|
path->slots[level] -= mid;
|
|
btrfs_tree_unlock(c);
|
|
free_extent_buffer(c);
|
|
path->nodes[level] = split;
|
|
path->slots[level + 1] += 1;
|
|
} else {
|
|
btrfs_tree_unlock(split);
|
|
free_extent_buffer(split);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* how many bytes are required to store the items in a leaf. start
|
|
* and nr indicate which items in the leaf to check. This totals up the
|
|
* space used both by the item structs and the item data
|
|
*/
|
|
static int leaf_space_used(struct extent_buffer *l, int start, int nr)
|
|
{
|
|
int data_len;
|
|
int nritems = btrfs_header_nritems(l);
|
|
int end = min(nritems, start + nr) - 1;
|
|
|
|
if (!nr)
|
|
return 0;
|
|
data_len = btrfs_item_offset(l, start) + btrfs_item_size(l, start);
|
|
data_len = data_len - btrfs_item_offset(l, end);
|
|
data_len += sizeof(struct btrfs_item) * nr;
|
|
WARN_ON(data_len < 0);
|
|
return data_len;
|
|
}
|
|
|
|
/*
|
|
* The space between the end of the leaf items and
|
|
* the start of the leaf data. IOW, how much room
|
|
* the leaf has left for both items and data
|
|
*/
|
|
noinline int btrfs_leaf_free_space(struct extent_buffer *leaf)
|
|
{
|
|
struct btrfs_fs_info *fs_info = leaf->fs_info;
|
|
int nritems = btrfs_header_nritems(leaf);
|
|
int ret;
|
|
|
|
ret = BTRFS_LEAF_DATA_SIZE(fs_info) - leaf_space_used(leaf, 0, nritems);
|
|
if (ret < 0) {
|
|
btrfs_crit(fs_info,
|
|
"leaf free space ret %d, leaf data size %lu, used %d nritems %d",
|
|
ret,
|
|
(unsigned long) BTRFS_LEAF_DATA_SIZE(fs_info),
|
|
leaf_space_used(leaf, 0, nritems), nritems);
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* min slot controls the lowest index we're willing to push to the
|
|
* right. We'll push up to and including min_slot, but no lower
|
|
*/
|
|
static noinline int __push_leaf_right(struct btrfs_trans_handle *trans,
|
|
struct btrfs_path *path,
|
|
int data_size, int empty,
|
|
struct extent_buffer *right,
|
|
int free_space, u32 left_nritems,
|
|
u32 min_slot)
|
|
{
|
|
struct btrfs_fs_info *fs_info = right->fs_info;
|
|
struct extent_buffer *left = path->nodes[0];
|
|
struct extent_buffer *upper = path->nodes[1];
|
|
struct btrfs_map_token token;
|
|
struct btrfs_disk_key disk_key;
|
|
int slot;
|
|
u32 i;
|
|
int push_space = 0;
|
|
int push_items = 0;
|
|
u32 nr;
|
|
u32 right_nritems;
|
|
u32 data_end;
|
|
u32 this_item_size;
|
|
|
|
if (empty)
|
|
nr = 0;
|
|
else
|
|
nr = max_t(u32, 1, min_slot);
|
|
|
|
if (path->slots[0] >= left_nritems)
|
|
push_space += data_size;
|
|
|
|
slot = path->slots[1];
|
|
i = left_nritems - 1;
|
|
while (i >= nr) {
|
|
if (!empty && push_items > 0) {
|
|
if (path->slots[0] > i)
|
|
break;
|
|
if (path->slots[0] == i) {
|
|
int space = btrfs_leaf_free_space(left);
|
|
|
|
if (space + push_space * 2 > free_space)
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (path->slots[0] == i)
|
|
push_space += data_size;
|
|
|
|
this_item_size = btrfs_item_size(left, i);
|
|
if (this_item_size + sizeof(struct btrfs_item) +
|
|
push_space > free_space)
|
|
break;
|
|
|
|
push_items++;
|
|
push_space += this_item_size + sizeof(struct btrfs_item);
|
|
if (i == 0)
|
|
break;
|
|
i--;
|
|
}
|
|
|
|
if (push_items == 0)
|
|
goto out_unlock;
|
|
|
|
WARN_ON(!empty && push_items == left_nritems);
|
|
|
|
/* push left to right */
|
|
right_nritems = btrfs_header_nritems(right);
|
|
|
|
push_space = btrfs_item_data_end(left, left_nritems - push_items);
|
|
push_space -= leaf_data_end(left);
|
|
|
|
/* make room in the right data area */
|
|
data_end = leaf_data_end(right);
|
|
memmove_leaf_data(right, data_end - push_space, data_end,
|
|
BTRFS_LEAF_DATA_SIZE(fs_info) - data_end);
|
|
|
|
/* copy from the left data area */
|
|
copy_leaf_data(right, left, BTRFS_LEAF_DATA_SIZE(fs_info) - push_space,
|
|
leaf_data_end(left), push_space);
|
|
|
|
memmove_leaf_items(right, push_items, 0, right_nritems);
|
|
|
|
/* copy the items from left to right */
|
|
copy_leaf_items(right, left, 0, left_nritems - push_items, push_items);
|
|
|
|
/* update the item pointers */
|
|
btrfs_init_map_token(&token, right);
|
|
right_nritems += push_items;
|
|
btrfs_set_header_nritems(right, right_nritems);
|
|
push_space = BTRFS_LEAF_DATA_SIZE(fs_info);
|
|
for (i = 0; i < right_nritems; i++) {
|
|
push_space -= btrfs_token_item_size(&token, i);
|
|
btrfs_set_token_item_offset(&token, i, push_space);
|
|
}
|
|
|
|
left_nritems -= push_items;
|
|
btrfs_set_header_nritems(left, left_nritems);
|
|
|
|
if (left_nritems)
|
|
btrfs_mark_buffer_dirty(left);
|
|
else
|
|
btrfs_clear_buffer_dirty(trans, left);
|
|
|
|
btrfs_mark_buffer_dirty(right);
|
|
|
|
btrfs_item_key(right, &disk_key, 0);
|
|
btrfs_set_node_key(upper, &disk_key, slot + 1);
|
|
btrfs_mark_buffer_dirty(upper);
|
|
|
|
/* then fixup the leaf pointer in the path */
|
|
if (path->slots[0] >= left_nritems) {
|
|
path->slots[0] -= left_nritems;
|
|
if (btrfs_header_nritems(path->nodes[0]) == 0)
|
|
btrfs_clear_buffer_dirty(trans, path->nodes[0]);
|
|
btrfs_tree_unlock(path->nodes[0]);
|
|
free_extent_buffer(path->nodes[0]);
|
|
path->nodes[0] = right;
|
|
path->slots[1] += 1;
|
|
} else {
|
|
btrfs_tree_unlock(right);
|
|
free_extent_buffer(right);
|
|
}
|
|
return 0;
|
|
|
|
out_unlock:
|
|
btrfs_tree_unlock(right);
|
|
free_extent_buffer(right);
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* push some data in the path leaf to the right, trying to free up at
|
|
* least data_size bytes. returns zero if the push worked, nonzero otherwise
|
|
*
|
|
* returns 1 if the push failed because the other node didn't have enough
|
|
* room, 0 if everything worked out and < 0 if there were major errors.
|
|
*
|
|
* this will push starting from min_slot to the end of the leaf. It won't
|
|
* push any slot lower than min_slot
|
|
*/
|
|
static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
|
|
*root, struct btrfs_path *path,
|
|
int min_data_size, int data_size,
|
|
int empty, u32 min_slot)
|
|
{
|
|
struct extent_buffer *left = path->nodes[0];
|
|
struct extent_buffer *right;
|
|
struct extent_buffer *upper;
|
|
int slot;
|
|
int free_space;
|
|
u32 left_nritems;
|
|
int ret;
|
|
|
|
if (!path->nodes[1])
|
|
return 1;
|
|
|
|
slot = path->slots[1];
|
|
upper = path->nodes[1];
|
|
if (slot >= btrfs_header_nritems(upper) - 1)
|
|
return 1;
|
|
|
|
btrfs_assert_tree_write_locked(path->nodes[1]);
|
|
|
|
right = btrfs_read_node_slot(upper, slot + 1);
|
|
/*
|
|
* slot + 1 is not valid or we fail to read the right node,
|
|
* no big deal, just return.
|
|
*/
|
|
if (IS_ERR(right))
|
|
return 1;
|
|
|
|
__btrfs_tree_lock(right, BTRFS_NESTING_RIGHT);
|
|
|
|
free_space = btrfs_leaf_free_space(right);
|
|
if (free_space < data_size)
|
|
goto out_unlock;
|
|
|
|
ret = btrfs_cow_block(trans, root, right, upper,
|
|
slot + 1, &right, BTRFS_NESTING_RIGHT_COW);
|
|
if (ret)
|
|
goto out_unlock;
|
|
|
|
left_nritems = btrfs_header_nritems(left);
|
|
if (left_nritems == 0)
|
|
goto out_unlock;
|
|
|
|
if (check_sibling_keys(left, right)) {
|
|
ret = -EUCLEAN;
|
|
btrfs_tree_unlock(right);
|
|
free_extent_buffer(right);
|
|
return ret;
|
|
}
|
|
if (path->slots[0] == left_nritems && !empty) {
|
|
/* Key greater than all keys in the leaf, right neighbor has
|
|
* enough room for it and we're not emptying our leaf to delete
|
|
* it, therefore use right neighbor to insert the new item and
|
|
* no need to touch/dirty our left leaf. */
|
|
btrfs_tree_unlock(left);
|
|
free_extent_buffer(left);
|
|
path->nodes[0] = right;
|
|
path->slots[0] = 0;
|
|
path->slots[1]++;
|
|
return 0;
|
|
}
|
|
|
|
return __push_leaf_right(trans, path, min_data_size, empty, right,
|
|
free_space, left_nritems, min_slot);
|
|
out_unlock:
|
|
btrfs_tree_unlock(right);
|
|
free_extent_buffer(right);
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* push some data in the path leaf to the left, trying to free up at
|
|
* least data_size bytes. returns zero if the push worked, nonzero otherwise
|
|
*
|
|
* max_slot can put a limit on how far into the leaf we'll push items. The
|
|
* item at 'max_slot' won't be touched. Use (u32)-1 to make us do all the
|
|
* items
|
|
*/
|
|
static noinline int __push_leaf_left(struct btrfs_trans_handle *trans,
|
|
struct btrfs_path *path, int data_size,
|
|
int empty, struct extent_buffer *left,
|
|
int free_space, u32 right_nritems,
|
|
u32 max_slot)
|
|
{
|
|
struct btrfs_fs_info *fs_info = left->fs_info;
|
|
struct btrfs_disk_key disk_key;
|
|
struct extent_buffer *right = path->nodes[0];
|
|
int i;
|
|
int push_space = 0;
|
|
int push_items = 0;
|
|
u32 old_left_nritems;
|
|
u32 nr;
|
|
int ret = 0;
|
|
u32 this_item_size;
|
|
u32 old_left_item_size;
|
|
struct btrfs_map_token token;
|
|
|
|
if (empty)
|
|
nr = min(right_nritems, max_slot);
|
|
else
|
|
nr = min(right_nritems - 1, max_slot);
|
|
|
|
for (i = 0; i < nr; i++) {
|
|
if (!empty && push_items > 0) {
|
|
if (path->slots[0] < i)
|
|
break;
|
|
if (path->slots[0] == i) {
|
|
int space = btrfs_leaf_free_space(right);
|
|
|
|
if (space + push_space * 2 > free_space)
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (path->slots[0] == i)
|
|
push_space += data_size;
|
|
|
|
this_item_size = btrfs_item_size(right, i);
|
|
if (this_item_size + sizeof(struct btrfs_item) + push_space >
|
|
free_space)
|
|
break;
|
|
|
|
push_items++;
|
|
push_space += this_item_size + sizeof(struct btrfs_item);
|
|
}
|
|
|
|
if (push_items == 0) {
|
|
ret = 1;
|
|
goto out;
|
|
}
|
|
WARN_ON(!empty && push_items == btrfs_header_nritems(right));
|
|
|
|
/* push data from right to left */
|
|
copy_leaf_items(left, right, btrfs_header_nritems(left), 0, push_items);
|
|
|
|
push_space = BTRFS_LEAF_DATA_SIZE(fs_info) -
|
|
btrfs_item_offset(right, push_items - 1);
|
|
|
|
copy_leaf_data(left, right, leaf_data_end(left) - push_space,
|
|
btrfs_item_offset(right, push_items - 1), push_space);
|
|
old_left_nritems = btrfs_header_nritems(left);
|
|
BUG_ON(old_left_nritems <= 0);
|
|
|
|
btrfs_init_map_token(&token, left);
|
|
old_left_item_size = btrfs_item_offset(left, old_left_nritems - 1);
|
|
for (i = old_left_nritems; i < old_left_nritems + push_items; i++) {
|
|
u32 ioff;
|
|
|
|
ioff = btrfs_token_item_offset(&token, i);
|
|
btrfs_set_token_item_offset(&token, i,
|
|
ioff - (BTRFS_LEAF_DATA_SIZE(fs_info) - old_left_item_size));
|
|
}
|
|
btrfs_set_header_nritems(left, old_left_nritems + push_items);
|
|
|
|
/* fixup right node */
|
|
if (push_items > right_nritems)
|
|
WARN(1, KERN_CRIT "push items %d nr %u\n", push_items,
|
|
right_nritems);
|
|
|
|
if (push_items < right_nritems) {
|
|
push_space = btrfs_item_offset(right, push_items - 1) -
|
|
leaf_data_end(right);
|
|
memmove_leaf_data(right,
|
|
BTRFS_LEAF_DATA_SIZE(fs_info) - push_space,
|
|
leaf_data_end(right), push_space);
|
|
|
|
memmove_leaf_items(right, 0, push_items,
|
|
btrfs_header_nritems(right) - push_items);
|
|
}
|
|
|
|
btrfs_init_map_token(&token, right);
|
|
right_nritems -= push_items;
|
|
btrfs_set_header_nritems(right, right_nritems);
|
|
push_space = BTRFS_LEAF_DATA_SIZE(fs_info);
|
|
for (i = 0; i < right_nritems; i++) {
|
|
push_space = push_space - btrfs_token_item_size(&token, i);
|
|
btrfs_set_token_item_offset(&token, i, push_space);
|
|
}
|
|
|
|
btrfs_mark_buffer_dirty(left);
|
|
if (right_nritems)
|
|
btrfs_mark_buffer_dirty(right);
|
|
else
|
|
btrfs_clear_buffer_dirty(trans, right);
|
|
|
|
btrfs_item_key(right, &disk_key, 0);
|
|
fixup_low_keys(path, &disk_key, 1);
|
|
|
|
/* then fixup the leaf pointer in the path */
|
|
if (path->slots[0] < push_items) {
|
|
path->slots[0] += old_left_nritems;
|
|
btrfs_tree_unlock(path->nodes[0]);
|
|
free_extent_buffer(path->nodes[0]);
|
|
path->nodes[0] = left;
|
|
path->slots[1] -= 1;
|
|
} else {
|
|
btrfs_tree_unlock(left);
|
|
free_extent_buffer(left);
|
|
path->slots[0] -= push_items;
|
|
}
|
|
BUG_ON(path->slots[0] < 0);
|
|
return ret;
|
|
out:
|
|
btrfs_tree_unlock(left);
|
|
free_extent_buffer(left);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* push some data in the path leaf to the left, trying to free up at
|
|
* least data_size bytes. returns zero if the push worked, nonzero otherwise
|
|
*
|
|
* max_slot can put a limit on how far into the leaf we'll push items. The
|
|
* item at 'max_slot' won't be touched. Use (u32)-1 to make us push all the
|
|
* items
|
|
*/
|
|
static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
|
|
*root, struct btrfs_path *path, int min_data_size,
|
|
int data_size, int empty, u32 max_slot)
|
|
{
|
|
struct extent_buffer *right = path->nodes[0];
|
|
struct extent_buffer *left;
|
|
int slot;
|
|
int free_space;
|
|
u32 right_nritems;
|
|
int ret = 0;
|
|
|
|
slot = path->slots[1];
|
|
if (slot == 0)
|
|
return 1;
|
|
if (!path->nodes[1])
|
|
return 1;
|
|
|
|
right_nritems = btrfs_header_nritems(right);
|
|
if (right_nritems == 0)
|
|
return 1;
|
|
|
|
btrfs_assert_tree_write_locked(path->nodes[1]);
|
|
|
|
left = btrfs_read_node_slot(path->nodes[1], slot - 1);
|
|
/*
|
|
* slot - 1 is not valid or we fail to read the left node,
|
|
* no big deal, just return.
|
|
*/
|
|
if (IS_ERR(left))
|
|
return 1;
|
|
|
|
__btrfs_tree_lock(left, BTRFS_NESTING_LEFT);
|
|
|
|
free_space = btrfs_leaf_free_space(left);
|
|
if (free_space < data_size) {
|
|
ret = 1;
|
|
goto out;
|
|
}
|
|
|
|
ret = btrfs_cow_block(trans, root, left,
|
|
path->nodes[1], slot - 1, &left,
|
|
BTRFS_NESTING_LEFT_COW);
|
|
if (ret) {
|
|
/* we hit -ENOSPC, but it isn't fatal here */
|
|
if (ret == -ENOSPC)
|
|
ret = 1;
|
|
goto out;
|
|
}
|
|
|
|
if (check_sibling_keys(left, right)) {
|
|
ret = -EUCLEAN;
|
|
goto out;
|
|
}
|
|
return __push_leaf_left(trans, path, min_data_size, empty, left,
|
|
free_space, right_nritems, max_slot);
|
|
out:
|
|
btrfs_tree_unlock(left);
|
|
free_extent_buffer(left);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* split the path's leaf in two, making sure there is at least data_size
|
|
* available for the resulting leaf level of the path.
|
|
*/
|
|
static noinline void copy_for_split(struct btrfs_trans_handle *trans,
|
|
struct btrfs_path *path,
|
|
struct extent_buffer *l,
|
|
struct extent_buffer *right,
|
|
int slot, int mid, int nritems)
|
|
{
|
|
struct btrfs_fs_info *fs_info = trans->fs_info;
|
|
int data_copy_size;
|
|
int rt_data_off;
|
|
int i;
|
|
struct btrfs_disk_key disk_key;
|
|
struct btrfs_map_token token;
|
|
|
|
nritems = nritems - mid;
|
|
btrfs_set_header_nritems(right, nritems);
|
|
data_copy_size = btrfs_item_data_end(l, mid) - leaf_data_end(l);
|
|
|
|
copy_leaf_items(right, l, 0, mid, nritems);
|
|
|
|
copy_leaf_data(right, l, BTRFS_LEAF_DATA_SIZE(fs_info) - data_copy_size,
|
|
leaf_data_end(l), data_copy_size);
|
|
|
|
rt_data_off = BTRFS_LEAF_DATA_SIZE(fs_info) - btrfs_item_data_end(l, mid);
|
|
|
|
btrfs_init_map_token(&token, right);
|
|
for (i = 0; i < nritems; i++) {
|
|
u32 ioff;
|
|
|
|
ioff = btrfs_token_item_offset(&token, i);
|
|
btrfs_set_token_item_offset(&token, i, ioff + rt_data_off);
|
|
}
|
|
|
|
btrfs_set_header_nritems(l, mid);
|
|
btrfs_item_key(right, &disk_key, 0);
|
|
insert_ptr(trans, path, &disk_key, right->start, path->slots[1] + 1, 1);
|
|
|
|
btrfs_mark_buffer_dirty(right);
|
|
btrfs_mark_buffer_dirty(l);
|
|
BUG_ON(path->slots[0] != slot);
|
|
|
|
if (mid <= slot) {
|
|
btrfs_tree_unlock(path->nodes[0]);
|
|
free_extent_buffer(path->nodes[0]);
|
|
path->nodes[0] = right;
|
|
path->slots[0] -= mid;
|
|
path->slots[1] += 1;
|
|
} else {
|
|
btrfs_tree_unlock(right);
|
|
free_extent_buffer(right);
|
|
}
|
|
|
|
BUG_ON(path->slots[0] < 0);
|
|
}
|
|
|
|
/*
|
|
* double splits happen when we need to insert a big item in the middle
|
|
* of a leaf. A double split can leave us with 3 mostly empty leaves:
|
|
* leaf: [ slots 0 - N] [ our target ] [ N + 1 - total in leaf ]
|
|
* A B C
|
|
*
|
|
* We avoid this by trying to push the items on either side of our target
|
|
* into the adjacent leaves. If all goes well we can avoid the double split
|
|
* completely.
|
|
*/
|
|
static noinline int push_for_double_split(struct btrfs_trans_handle *trans,
|
|
struct btrfs_root *root,
|
|
struct btrfs_path *path,
|
|
int data_size)
|
|
{
|
|
int ret;
|
|
int progress = 0;
|
|
int slot;
|
|
u32 nritems;
|
|
int space_needed = data_size;
|
|
|
|
slot = path->slots[0];
|
|
if (slot < btrfs_header_nritems(path->nodes[0]))
|
|
space_needed -= btrfs_leaf_free_space(path->nodes[0]);
|
|
|
|
/*
|
|
* try to push all the items after our slot into the
|
|
* right leaf
|
|
*/
|
|
ret = push_leaf_right(trans, root, path, 1, space_needed, 0, slot);
|
|
if (ret < 0)
|
|
return ret;
|
|
|
|
if (ret == 0)
|
|
progress++;
|
|
|
|
nritems = btrfs_header_nritems(path->nodes[0]);
|
|
/*
|
|
* our goal is to get our slot at the start or end of a leaf. If
|
|
* we've done so we're done
|
|
*/
|
|
if (path->slots[0] == 0 || path->slots[0] == nritems)
|
|
return 0;
|
|
|
|
if (btrfs_leaf_free_space(path->nodes[0]) >= data_size)
|
|
return 0;
|
|
|
|
/* try to push all the items before our slot into the next leaf */
|
|
slot = path->slots[0];
|
|
space_needed = data_size;
|
|
if (slot > 0)
|
|
space_needed -= btrfs_leaf_free_space(path->nodes[0]);
|
|
ret = push_leaf_left(trans, root, path, 1, space_needed, 0, slot);
|
|
if (ret < 0)
|
|
return ret;
|
|
|
|
if (ret == 0)
|
|
progress++;
|
|
|
|
if (progress)
|
|
return 0;
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* split the path's leaf in two, making sure there is at least data_size
|
|
* available for the resulting leaf level of the path.
|
|
*
|
|
* returns 0 if all went well and < 0 on failure.
|
|
*/
|
|
static noinline int split_leaf(struct btrfs_trans_handle *trans,
|
|
struct btrfs_root *root,
|
|
const struct btrfs_key *ins_key,
|
|
struct btrfs_path *path, int data_size,
|
|
int extend)
|
|
{
|
|
struct btrfs_disk_key disk_key;
|
|
struct extent_buffer *l;
|
|
u32 nritems;
|
|
int mid;
|
|
int slot;
|
|
struct extent_buffer *right;
|
|
struct btrfs_fs_info *fs_info = root->fs_info;
|
|
int ret = 0;
|
|
int wret;
|
|
int split;
|
|
int num_doubles = 0;
|
|
int tried_avoid_double = 0;
|
|
|
|
l = path->nodes[0];
|
|
slot = path->slots[0];
|
|
if (extend && data_size + btrfs_item_size(l, slot) +
|
|
sizeof(struct btrfs_item) > BTRFS_LEAF_DATA_SIZE(fs_info))
|
|
return -EOVERFLOW;
|
|
|
|
/* first try to make some room by pushing left and right */
|
|
if (data_size && path->nodes[1]) {
|
|
int space_needed = data_size;
|
|
|
|
if (slot < btrfs_header_nritems(l))
|
|
space_needed -= btrfs_leaf_free_space(l);
|
|
|
|
wret = push_leaf_right(trans, root, path, space_needed,
|
|
space_needed, 0, 0);
|
|
if (wret < 0)
|
|
return wret;
|
|
if (wret) {
|
|
space_needed = data_size;
|
|
if (slot > 0)
|
|
space_needed -= btrfs_leaf_free_space(l);
|
|
wret = push_leaf_left(trans, root, path, space_needed,
|
|
space_needed, 0, (u32)-1);
|
|
if (wret < 0)
|
|
return wret;
|
|
}
|
|
l = path->nodes[0];
|
|
|
|
/* did the pushes work? */
|
|
if (btrfs_leaf_free_space(l) >= data_size)
|
|
return 0;
|
|
}
|
|
|
|
if (!path->nodes[1]) {
|
|
ret = insert_new_root(trans, root, path, 1);
|
|
if (ret)
|
|
return ret;
|
|
}
|
|
again:
|
|
split = 1;
|
|
l = path->nodes[0];
|
|
slot = path->slots[0];
|
|
nritems = btrfs_header_nritems(l);
|
|
mid = (nritems + 1) / 2;
|
|
|
|
if (mid <= slot) {
|
|
if (nritems == 1 ||
|
|
leaf_space_used(l, mid, nritems - mid) + data_size >
|
|
BTRFS_LEAF_DATA_SIZE(fs_info)) {
|
|
if (slot >= nritems) {
|
|
split = 0;
|
|
} else {
|
|
mid = slot;
|
|
if (mid != nritems &&
|
|
leaf_space_used(l, mid, nritems - mid) +
|
|
data_size > BTRFS_LEAF_DATA_SIZE(fs_info)) {
|
|
if (data_size && !tried_avoid_double)
|
|
goto push_for_double;
|
|
split = 2;
|
|
}
|
|
}
|
|
}
|
|
} else {
|
|
if (leaf_space_used(l, 0, mid) + data_size >
|
|
BTRFS_LEAF_DATA_SIZE(fs_info)) {
|
|
if (!extend && data_size && slot == 0) {
|
|
split = 0;
|
|
} else if ((extend || !data_size) && slot == 0) {
|
|
mid = 1;
|
|
} else {
|
|
mid = slot;
|
|
if (mid != nritems &&
|
|
leaf_space_used(l, mid, nritems - mid) +
|
|
data_size > BTRFS_LEAF_DATA_SIZE(fs_info)) {
|
|
if (data_size && !tried_avoid_double)
|
|
goto push_for_double;
|
|
split = 2;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
if (split == 0)
|
|
btrfs_cpu_key_to_disk(&disk_key, ins_key);
|
|
else
|
|
btrfs_item_key(l, &disk_key, mid);
|
|
|
|
/*
|
|
* We have to about BTRFS_NESTING_NEW_ROOT here if we've done a double
|
|
* split, because we're only allowed to have MAX_LOCKDEP_SUBCLASSES
|
|
* subclasses, which is 8 at the time of this patch, and we've maxed it
|
|
* out. In the future we could add a
|
|
* BTRFS_NESTING_SPLIT_THE_SPLITTENING if we need to, but for now just
|
|
* use BTRFS_NESTING_NEW_ROOT.
|
|
*/
|
|
right = btrfs_alloc_tree_block(trans, root, 0, root->root_key.objectid,
|
|
&disk_key, 0, l->start, 0,
|
|
num_doubles ? BTRFS_NESTING_NEW_ROOT :
|
|
BTRFS_NESTING_SPLIT);
|
|
if (IS_ERR(right))
|
|
return PTR_ERR(right);
|
|
|
|
root_add_used(root, fs_info->nodesize);
|
|
|
|
if (split == 0) {
|
|
if (mid <= slot) {
|
|
btrfs_set_header_nritems(right, 0);
|
|
insert_ptr(trans, path, &disk_key,
|
|
right->start, path->slots[1] + 1, 1);
|
|
btrfs_tree_unlock(path->nodes[0]);
|
|
free_extent_buffer(path->nodes[0]);
|
|
path->nodes[0] = right;
|
|
path->slots[0] = 0;
|
|
path->slots[1] += 1;
|
|
} else {
|
|
btrfs_set_header_nritems(right, 0);
|
|
insert_ptr(trans, path, &disk_key,
|
|
right->start, path->slots[1], 1);
|
|
btrfs_tree_unlock(path->nodes[0]);
|
|
free_extent_buffer(path->nodes[0]);
|
|
path->nodes[0] = right;
|
|
path->slots[0] = 0;
|
|
if (path->slots[1] == 0)
|
|
fixup_low_keys(path, &disk_key, 1);
|
|
}
|
|
/*
|
|
* We create a new leaf 'right' for the required ins_len and
|
|
* we'll do btrfs_mark_buffer_dirty() on this leaf after copying
|
|
* the content of ins_len to 'right'.
|
|
*/
|
|
return ret;
|
|
}
|
|
|
|
copy_for_split(trans, path, l, right, slot, mid, nritems);
|
|
|
|
if (split == 2) {
|
|
BUG_ON(num_doubles != 0);
|
|
num_doubles++;
|
|
goto again;
|
|
}
|
|
|
|
return 0;
|
|
|
|
push_for_double:
|
|
push_for_double_split(trans, root, path, data_size);
|
|
tried_avoid_double = 1;
|
|
if (btrfs_leaf_free_space(path->nodes[0]) >= data_size)
|
|
return 0;
|
|
goto again;
|
|
}
|
|
|
|
static noinline int setup_leaf_for_split(struct btrfs_trans_handle *trans,
|
|
struct btrfs_root *root,
|
|
struct btrfs_path *path, int ins_len)
|
|
{
|
|
struct btrfs_key key;
|
|
struct extent_buffer *leaf;
|
|
struct btrfs_file_extent_item *fi;
|
|
u64 extent_len = 0;
|
|
u32 item_size;
|
|
int ret;
|
|
|
|
leaf = path->nodes[0];
|
|
btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
|
|
|
|
BUG_ON(key.type != BTRFS_EXTENT_DATA_KEY &&
|
|
key.type != BTRFS_EXTENT_CSUM_KEY);
|
|
|
|
if (btrfs_leaf_free_space(leaf) >= ins_len)
|
|
return 0;
|
|
|
|
item_size = btrfs_item_size(leaf, path->slots[0]);
|
|
if (key.type == BTRFS_EXTENT_DATA_KEY) {
|
|
fi = btrfs_item_ptr(leaf, path->slots[0],
|
|
struct btrfs_file_extent_item);
|
|
extent_len = btrfs_file_extent_num_bytes(leaf, fi);
|
|
}
|
|
btrfs_release_path(path);
|
|
|
|
path->keep_locks = 1;
|
|
path->search_for_split = 1;
|
|
ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
|
|
path->search_for_split = 0;
|
|
if (ret > 0)
|
|
ret = -EAGAIN;
|
|
if (ret < 0)
|
|
goto err;
|
|
|
|
ret = -EAGAIN;
|
|
leaf = path->nodes[0];
|
|
/* if our item isn't there, return now */
|
|
if (item_size != btrfs_item_size(leaf, path->slots[0]))
|
|
goto err;
|
|
|
|
/* the leaf has changed, it now has room. return now */
|
|
if (btrfs_leaf_free_space(path->nodes[0]) >= ins_len)
|
|
goto err;
|
|
|
|
if (key.type == BTRFS_EXTENT_DATA_KEY) {
|
|
fi = btrfs_item_ptr(leaf, path->slots[0],
|
|
struct btrfs_file_extent_item);
|
|
if (extent_len != btrfs_file_extent_num_bytes(leaf, fi))
|
|
goto err;
|
|
}
|
|
|
|
ret = split_leaf(trans, root, &key, path, ins_len, 1);
|
|
if (ret)
|
|
goto err;
|
|
|
|
path->keep_locks = 0;
|
|
btrfs_unlock_up_safe(path, 1);
|
|
return 0;
|
|
err:
|
|
path->keep_locks = 0;
|
|
return ret;
|
|
}
|
|
|
|
static noinline int split_item(struct btrfs_path *path,
|
|
const struct btrfs_key *new_key,
|
|
unsigned long split_offset)
|
|
{
|
|
struct extent_buffer *leaf;
|
|
int orig_slot, slot;
|
|
char *buf;
|
|
u32 nritems;
|
|
u32 item_size;
|
|
u32 orig_offset;
|
|
struct btrfs_disk_key disk_key;
|
|
|
|
leaf = path->nodes[0];
|
|
BUG_ON(btrfs_leaf_free_space(leaf) < sizeof(struct btrfs_item));
|
|
|
|
orig_slot = path->slots[0];
|
|
orig_offset = btrfs_item_offset(leaf, path->slots[0]);
|
|
item_size = btrfs_item_size(leaf, path->slots[0]);
|
|
|
|
buf = kmalloc(item_size, GFP_NOFS);
|
|
if (!buf)
|
|
return -ENOMEM;
|
|
|
|
read_extent_buffer(leaf, buf, btrfs_item_ptr_offset(leaf,
|
|
path->slots[0]), item_size);
|
|
|
|
slot = path->slots[0] + 1;
|
|
nritems = btrfs_header_nritems(leaf);
|
|
if (slot != nritems) {
|
|
/* shift the items */
|
|
memmove_leaf_items(leaf, slot + 1, slot, nritems - slot);
|
|
}
|
|
|
|
btrfs_cpu_key_to_disk(&disk_key, new_key);
|
|
btrfs_set_item_key(leaf, &disk_key, slot);
|
|
|
|
btrfs_set_item_offset(leaf, slot, orig_offset);
|
|
btrfs_set_item_size(leaf, slot, item_size - split_offset);
|
|
|
|
btrfs_set_item_offset(leaf, orig_slot,
|
|
orig_offset + item_size - split_offset);
|
|
btrfs_set_item_size(leaf, orig_slot, split_offset);
|
|
|
|
btrfs_set_header_nritems(leaf, nritems + 1);
|
|
|
|
/* write the data for the start of the original item */
|
|
write_extent_buffer(leaf, buf,
|
|
btrfs_item_ptr_offset(leaf, path->slots[0]),
|
|
split_offset);
|
|
|
|
/* write the data for the new item */
|
|
write_extent_buffer(leaf, buf + split_offset,
|
|
btrfs_item_ptr_offset(leaf, slot),
|
|
item_size - split_offset);
|
|
btrfs_mark_buffer_dirty(leaf);
|
|
|
|
BUG_ON(btrfs_leaf_free_space(leaf) < 0);
|
|
kfree(buf);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* This function splits a single item into two items,
|
|
* giving 'new_key' to the new item and splitting the
|
|
* old one at split_offset (from the start of the item).
|
|
*
|
|
* The path may be released by this operation. After
|
|
* the split, the path is pointing to the old item. The
|
|
* new item is going to be in the same node as the old one.
|
|
*
|
|
* Note, the item being split must be smaller enough to live alone on
|
|
* a tree block with room for one extra struct btrfs_item
|
|
*
|
|
* This allows us to split the item in place, keeping a lock on the
|
|
* leaf the entire time.
|
|
*/
|
|
int btrfs_split_item(struct btrfs_trans_handle *trans,
|
|
struct btrfs_root *root,
|
|
struct btrfs_path *path,
|
|
const struct btrfs_key *new_key,
|
|
unsigned long split_offset)
|
|
{
|
|
int ret;
|
|
ret = setup_leaf_for_split(trans, root, path,
|
|
sizeof(struct btrfs_item));
|
|
if (ret)
|
|
return ret;
|
|
|
|
ret = split_item(path, new_key, split_offset);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* make the item pointed to by the path smaller. new_size indicates
|
|
* how small to make it, and from_end tells us if we just chop bytes
|
|
* off the end of the item or if we shift the item to chop bytes off
|
|
* the front.
|
|
*/
|
|
void btrfs_truncate_item(struct btrfs_path *path, u32 new_size, int from_end)
|
|
{
|
|
int slot;
|
|
struct extent_buffer *leaf;
|
|
u32 nritems;
|
|
unsigned int data_end;
|
|
unsigned int old_data_start;
|
|
unsigned int old_size;
|
|
unsigned int size_diff;
|
|
int i;
|
|
struct btrfs_map_token token;
|
|
|
|
leaf = path->nodes[0];
|
|
slot = path->slots[0];
|
|
|
|
old_size = btrfs_item_size(leaf, slot);
|
|
if (old_size == new_size)
|
|
return;
|
|
|
|
nritems = btrfs_header_nritems(leaf);
|
|
data_end = leaf_data_end(leaf);
|
|
|
|
old_data_start = btrfs_item_offset(leaf, slot);
|
|
|
|
size_diff = old_size - new_size;
|
|
|
|
BUG_ON(slot < 0);
|
|
BUG_ON(slot >= nritems);
|
|
|
|
/*
|
|
* item0..itemN ... dataN.offset..dataN.size .. data0.size
|
|
*/
|
|
/* first correct the data pointers */
|
|
btrfs_init_map_token(&token, leaf);
|
|
for (i = slot; i < nritems; i++) {
|
|
u32 ioff;
|
|
|
|
ioff = btrfs_token_item_offset(&token, i);
|
|
btrfs_set_token_item_offset(&token, i, ioff + size_diff);
|
|
}
|
|
|
|
/* shift the data */
|
|
if (from_end) {
|
|
memmove_leaf_data(leaf, data_end + size_diff, data_end,
|
|
old_data_start + new_size - data_end);
|
|
} else {
|
|
struct btrfs_disk_key disk_key;
|
|
u64 offset;
|
|
|
|
btrfs_item_key(leaf, &disk_key, slot);
|
|
|
|
if (btrfs_disk_key_type(&disk_key) == BTRFS_EXTENT_DATA_KEY) {
|
|
unsigned long ptr;
|
|
struct btrfs_file_extent_item *fi;
|
|
|
|
fi = btrfs_item_ptr(leaf, slot,
|
|
struct btrfs_file_extent_item);
|
|
fi = (struct btrfs_file_extent_item *)(
|
|
(unsigned long)fi - size_diff);
|
|
|
|
if (btrfs_file_extent_type(leaf, fi) ==
|
|
BTRFS_FILE_EXTENT_INLINE) {
|
|
ptr = btrfs_item_ptr_offset(leaf, slot);
|
|
memmove_extent_buffer(leaf, ptr,
|
|
(unsigned long)fi,
|
|
BTRFS_FILE_EXTENT_INLINE_DATA_START);
|
|
}
|
|
}
|
|
|
|
memmove_leaf_data(leaf, data_end + size_diff, data_end,
|
|
old_data_start - data_end);
|
|
|
|
offset = btrfs_disk_key_offset(&disk_key);
|
|
btrfs_set_disk_key_offset(&disk_key, offset + size_diff);
|
|
btrfs_set_item_key(leaf, &disk_key, slot);
|
|
if (slot == 0)
|
|
fixup_low_keys(path, &disk_key, 1);
|
|
}
|
|
|
|
btrfs_set_item_size(leaf, slot, new_size);
|
|
btrfs_mark_buffer_dirty(leaf);
|
|
|
|
if (btrfs_leaf_free_space(leaf) < 0) {
|
|
btrfs_print_leaf(leaf);
|
|
BUG();
|
|
}
|
|
}
|
|
|
|
/*
|
|
* make the item pointed to by the path bigger, data_size is the added size.
|
|
*/
|
|
void btrfs_extend_item(struct btrfs_path *path, u32 data_size)
|
|
{
|
|
int slot;
|
|
struct extent_buffer *leaf;
|
|
u32 nritems;
|
|
unsigned int data_end;
|
|
unsigned int old_data;
|
|
unsigned int old_size;
|
|
int i;
|
|
struct btrfs_map_token token;
|
|
|
|
leaf = path->nodes[0];
|
|
|
|
nritems = btrfs_header_nritems(leaf);
|
|
data_end = leaf_data_end(leaf);
|
|
|
|
if (btrfs_leaf_free_space(leaf) < data_size) {
|
|
btrfs_print_leaf(leaf);
|
|
BUG();
|
|
}
|
|
slot = path->slots[0];
|
|
old_data = btrfs_item_data_end(leaf, slot);
|
|
|
|
BUG_ON(slot < 0);
|
|
if (slot >= nritems) {
|
|
btrfs_print_leaf(leaf);
|
|
btrfs_crit(leaf->fs_info, "slot %d too large, nritems %d",
|
|
slot, nritems);
|
|
BUG();
|
|
}
|
|
|
|
/*
|
|
* item0..itemN ... dataN.offset..dataN.size .. data0.size
|
|
*/
|
|
/* first correct the data pointers */
|
|
btrfs_init_map_token(&token, leaf);
|
|
for (i = slot; i < nritems; i++) {
|
|
u32 ioff;
|
|
|
|
ioff = btrfs_token_item_offset(&token, i);
|
|
btrfs_set_token_item_offset(&token, i, ioff - data_size);
|
|
}
|
|
|
|
/* shift the data */
|
|
memmove_leaf_data(leaf, data_end - data_size, data_end,
|
|
old_data - data_end);
|
|
|
|
data_end = old_data;
|
|
old_size = btrfs_item_size(leaf, slot);
|
|
btrfs_set_item_size(leaf, slot, old_size + data_size);
|
|
btrfs_mark_buffer_dirty(leaf);
|
|
|
|
if (btrfs_leaf_free_space(leaf) < 0) {
|
|
btrfs_print_leaf(leaf);
|
|
BUG();
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Make space in the node before inserting one or more items.
|
|
*
|
|
* @root: root we are inserting items to
|
|
* @path: points to the leaf/slot where we are going to insert new items
|
|
* @batch: information about the batch of items to insert
|
|
*
|
|
* Main purpose is to save stack depth by doing the bulk of the work in a
|
|
* function that doesn't call btrfs_search_slot
|
|
*/
|
|
static void setup_items_for_insert(struct btrfs_root *root, struct btrfs_path *path,
|
|
const struct btrfs_item_batch *batch)
|
|
{
|
|
struct btrfs_fs_info *fs_info = root->fs_info;
|
|
int i;
|
|
u32 nritems;
|
|
unsigned int data_end;
|
|
struct btrfs_disk_key disk_key;
|
|
struct extent_buffer *leaf;
|
|
int slot;
|
|
struct btrfs_map_token token;
|
|
u32 total_size;
|
|
|
|
/*
|
|
* Before anything else, update keys in the parent and other ancestors
|
|
* if needed, then release the write locks on them, so that other tasks
|
|
* can use them while we modify the leaf.
|
|
*/
|
|
if (path->slots[0] == 0) {
|
|
btrfs_cpu_key_to_disk(&disk_key, &batch->keys[0]);
|
|
fixup_low_keys(path, &disk_key, 1);
|
|
}
|
|
btrfs_unlock_up_safe(path, 1);
|
|
|
|
leaf = path->nodes[0];
|
|
slot = path->slots[0];
|
|
|
|
nritems = btrfs_header_nritems(leaf);
|
|
data_end = leaf_data_end(leaf);
|
|
total_size = batch->total_data_size + (batch->nr * sizeof(struct btrfs_item));
|
|
|
|
if (btrfs_leaf_free_space(leaf) < total_size) {
|
|
btrfs_print_leaf(leaf);
|
|
btrfs_crit(fs_info, "not enough freespace need %u have %d",
|
|
total_size, btrfs_leaf_free_space(leaf));
|
|
BUG();
|
|
}
|
|
|
|
btrfs_init_map_token(&token, leaf);
|
|
if (slot != nritems) {
|
|
unsigned int old_data = btrfs_item_data_end(leaf, slot);
|
|
|
|
if (old_data < data_end) {
|
|
btrfs_print_leaf(leaf);
|
|
btrfs_crit(fs_info,
|
|
"item at slot %d with data offset %u beyond data end of leaf %u",
|
|
slot, old_data, data_end);
|
|
BUG();
|
|
}
|
|
/*
|
|
* item0..itemN ... dataN.offset..dataN.size .. data0.size
|
|
*/
|
|
/* first correct the data pointers */
|
|
for (i = slot; i < nritems; i++) {
|
|
u32 ioff;
|
|
|
|
ioff = btrfs_token_item_offset(&token, i);
|
|
btrfs_set_token_item_offset(&token, i,
|
|
ioff - batch->total_data_size);
|
|
}
|
|
/* shift the items */
|
|
memmove_leaf_items(leaf, slot + batch->nr, slot, nritems - slot);
|
|
|
|
/* shift the data */
|
|
memmove_leaf_data(leaf, data_end - batch->total_data_size,
|
|
data_end, old_data - data_end);
|
|
data_end = old_data;
|
|
}
|
|
|
|
/* setup the item for the new data */
|
|
for (i = 0; i < batch->nr; i++) {
|
|
btrfs_cpu_key_to_disk(&disk_key, &batch->keys[i]);
|
|
btrfs_set_item_key(leaf, &disk_key, slot + i);
|
|
data_end -= batch->data_sizes[i];
|
|
btrfs_set_token_item_offset(&token, slot + i, data_end);
|
|
btrfs_set_token_item_size(&token, slot + i, batch->data_sizes[i]);
|
|
}
|
|
|
|
btrfs_set_header_nritems(leaf, nritems + batch->nr);
|
|
btrfs_mark_buffer_dirty(leaf);
|
|
|
|
if (btrfs_leaf_free_space(leaf) < 0) {
|
|
btrfs_print_leaf(leaf);
|
|
BUG();
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Insert a new item into a leaf.
|
|
*
|
|
* @root: The root of the btree.
|
|
* @path: A path pointing to the target leaf and slot.
|
|
* @key: The key of the new item.
|
|
* @data_size: The size of the data associated with the new key.
|
|
*/
|
|
void btrfs_setup_item_for_insert(struct btrfs_root *root,
|
|
struct btrfs_path *path,
|
|
const struct btrfs_key *key,
|
|
u32 data_size)
|
|
{
|
|
struct btrfs_item_batch batch;
|
|
|
|
batch.keys = key;
|
|
batch.data_sizes = &data_size;
|
|
batch.total_data_size = data_size;
|
|
batch.nr = 1;
|
|
|
|
setup_items_for_insert(root, path, &batch);
|
|
}
|
|
|
|
/*
|
|
* Given a key and some data, insert items into the tree.
|
|
* This does all the path init required, making room in the tree if needed.
|
|
*/
|
|
int btrfs_insert_empty_items(struct btrfs_trans_handle *trans,
|
|
struct btrfs_root *root,
|
|
struct btrfs_path *path,
|
|
const struct btrfs_item_batch *batch)
|
|
{
|
|
int ret = 0;
|
|
int slot;
|
|
u32 total_size;
|
|
|
|
total_size = batch->total_data_size + (batch->nr * sizeof(struct btrfs_item));
|
|
ret = btrfs_search_slot(trans, root, &batch->keys[0], path, total_size, 1);
|
|
if (ret == 0)
|
|
return -EEXIST;
|
|
if (ret < 0)
|
|
return ret;
|
|
|
|
slot = path->slots[0];
|
|
BUG_ON(slot < 0);
|
|
|
|
setup_items_for_insert(root, path, batch);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Given a key and some data, insert an item into the tree.
|
|
* This does all the path init required, making room in the tree if needed.
|
|
*/
|
|
int btrfs_insert_item(struct btrfs_trans_handle *trans, struct btrfs_root *root,
|
|
const struct btrfs_key *cpu_key, void *data,
|
|
u32 data_size)
|
|
{
|
|
int ret = 0;
|
|
struct btrfs_path *path;
|
|
struct extent_buffer *leaf;
|
|
unsigned long ptr;
|
|
|
|
path = btrfs_alloc_path();
|
|
if (!path)
|
|
return -ENOMEM;
|
|
ret = btrfs_insert_empty_item(trans, root, path, cpu_key, data_size);
|
|
if (!ret) {
|
|
leaf = path->nodes[0];
|
|
ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
|
|
write_extent_buffer(leaf, data, ptr, data_size);
|
|
btrfs_mark_buffer_dirty(leaf);
|
|
}
|
|
btrfs_free_path(path);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* This function duplicates an item, giving 'new_key' to the new item.
|
|
* It guarantees both items live in the same tree leaf and the new item is
|
|
* contiguous with the original item.
|
|
*
|
|
* This allows us to split a file extent in place, keeping a lock on the leaf
|
|
* the entire time.
|
|
*/
|
|
int btrfs_duplicate_item(struct btrfs_trans_handle *trans,
|
|
struct btrfs_root *root,
|
|
struct btrfs_path *path,
|
|
const struct btrfs_key *new_key)
|
|
{
|
|
struct extent_buffer *leaf;
|
|
int ret;
|
|
u32 item_size;
|
|
|
|
leaf = path->nodes[0];
|
|
item_size = btrfs_item_size(leaf, path->slots[0]);
|
|
ret = setup_leaf_for_split(trans, root, path,
|
|
item_size + sizeof(struct btrfs_item));
|
|
if (ret)
|
|
return ret;
|
|
|
|
path->slots[0]++;
|
|
btrfs_setup_item_for_insert(root, path, new_key, item_size);
|
|
leaf = path->nodes[0];
|
|
memcpy_extent_buffer(leaf,
|
|
btrfs_item_ptr_offset(leaf, path->slots[0]),
|
|
btrfs_item_ptr_offset(leaf, path->slots[0] - 1),
|
|
item_size);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* delete the pointer from a given node.
|
|
*
|
|
* the tree should have been previously balanced so the deletion does not
|
|
* empty a node.
|
|
*/
|
|
static void del_ptr(struct btrfs_root *root, struct btrfs_path *path,
|
|
int level, int slot)
|
|
{
|
|
struct extent_buffer *parent = path->nodes[level];
|
|
u32 nritems;
|
|
int ret;
|
|
|
|
nritems = btrfs_header_nritems(parent);
|
|
if (slot != nritems - 1) {
|
|
if (level) {
|
|
ret = btrfs_tree_mod_log_insert_move(parent, slot,
|
|
slot + 1, nritems - slot - 1);
|
|
BUG_ON(ret < 0);
|
|
}
|
|
memmove_extent_buffer(parent,
|
|
btrfs_node_key_ptr_offset(parent, slot),
|
|
btrfs_node_key_ptr_offset(parent, slot + 1),
|
|
sizeof(struct btrfs_key_ptr) *
|
|
(nritems - slot - 1));
|
|
} else if (level) {
|
|
ret = btrfs_tree_mod_log_insert_key(parent, slot,
|
|
BTRFS_MOD_LOG_KEY_REMOVE);
|
|
BUG_ON(ret < 0);
|
|
}
|
|
|
|
nritems--;
|
|
btrfs_set_header_nritems(parent, nritems);
|
|
if (nritems == 0 && parent == root->node) {
|
|
BUG_ON(btrfs_header_level(root->node) != 1);
|
|
/* just turn the root into a leaf and break */
|
|
btrfs_set_header_level(root->node, 0);
|
|
} else if (slot == 0) {
|
|
struct btrfs_disk_key disk_key;
|
|
|
|
btrfs_node_key(parent, &disk_key, 0);
|
|
fixup_low_keys(path, &disk_key, level + 1);
|
|
}
|
|
btrfs_mark_buffer_dirty(parent);
|
|
}
|
|
|
|
/*
|
|
* a helper function to delete the leaf pointed to by path->slots[1] and
|
|
* path->nodes[1].
|
|
*
|
|
* This deletes the pointer in path->nodes[1] and frees the leaf
|
|
* block extent. zero is returned if it all worked out, < 0 otherwise.
|
|
*
|
|
* The path must have already been setup for deleting the leaf, including
|
|
* all the proper balancing. path->nodes[1] must be locked.
|
|
*/
|
|
static noinline void btrfs_del_leaf(struct btrfs_trans_handle *trans,
|
|
struct btrfs_root *root,
|
|
struct btrfs_path *path,
|
|
struct extent_buffer *leaf)
|
|
{
|
|
WARN_ON(btrfs_header_generation(leaf) != trans->transid);
|
|
del_ptr(root, path, 1, path->slots[1]);
|
|
|
|
/*
|
|
* btrfs_free_extent is expensive, we want to make sure we
|
|
* aren't holding any locks when we call it
|
|
*/
|
|
btrfs_unlock_up_safe(path, 0);
|
|
|
|
root_sub_used(root, leaf->len);
|
|
|
|
atomic_inc(&leaf->refs);
|
|
btrfs_free_tree_block(trans, btrfs_root_id(root), leaf, 0, 1);
|
|
free_extent_buffer_stale(leaf);
|
|
}
|
|
/*
|
|
* delete the item at the leaf level in path. If that empties
|
|
* the leaf, remove it from the tree
|
|
*/
|
|
int btrfs_del_items(struct btrfs_trans_handle *trans, struct btrfs_root *root,
|
|
struct btrfs_path *path, int slot, int nr)
|
|
{
|
|
struct btrfs_fs_info *fs_info = root->fs_info;
|
|
struct extent_buffer *leaf;
|
|
int ret = 0;
|
|
int wret;
|
|
u32 nritems;
|
|
|
|
leaf = path->nodes[0];
|
|
nritems = btrfs_header_nritems(leaf);
|
|
|
|
if (slot + nr != nritems) {
|
|
const u32 last_off = btrfs_item_offset(leaf, slot + nr - 1);
|
|
const int data_end = leaf_data_end(leaf);
|
|
struct btrfs_map_token token;
|
|
u32 dsize = 0;
|
|
int i;
|
|
|
|
for (i = 0; i < nr; i++)
|
|
dsize += btrfs_item_size(leaf, slot + i);
|
|
|
|
memmove_leaf_data(leaf, data_end + dsize, data_end,
|
|
last_off - data_end);
|
|
|
|
btrfs_init_map_token(&token, leaf);
|
|
for (i = slot + nr; i < nritems; i++) {
|
|
u32 ioff;
|
|
|
|
ioff = btrfs_token_item_offset(&token, i);
|
|
btrfs_set_token_item_offset(&token, i, ioff + dsize);
|
|
}
|
|
|
|
memmove_leaf_items(leaf, slot, slot + nr, nritems - slot - nr);
|
|
}
|
|
btrfs_set_header_nritems(leaf, nritems - nr);
|
|
nritems -= nr;
|
|
|
|
/* delete the leaf if we've emptied it */
|
|
if (nritems == 0) {
|
|
if (leaf == root->node) {
|
|
btrfs_set_header_level(leaf, 0);
|
|
} else {
|
|
btrfs_clear_buffer_dirty(trans, leaf);
|
|
btrfs_del_leaf(trans, root, path, leaf);
|
|
}
|
|
} else {
|
|
int used = leaf_space_used(leaf, 0, nritems);
|
|
if (slot == 0) {
|
|
struct btrfs_disk_key disk_key;
|
|
|
|
btrfs_item_key(leaf, &disk_key, 0);
|
|
fixup_low_keys(path, &disk_key, 1);
|
|
}
|
|
|
|
/*
|
|
* Try to delete the leaf if it is mostly empty. We do this by
|
|
* trying to move all its items into its left and right neighbours.
|
|
* If we can't move all the items, then we don't delete it - it's
|
|
* not ideal, but future insertions might fill the leaf with more
|
|
* items, or items from other leaves might be moved later into our
|
|
* leaf due to deletions on those leaves.
|
|
*/
|
|
if (used < BTRFS_LEAF_DATA_SIZE(fs_info) / 3) {
|
|
u32 min_push_space;
|
|
|
|
/* push_leaf_left fixes the path.
|
|
* make sure the path still points to our leaf
|
|
* for possible call to del_ptr below
|
|
*/
|
|
slot = path->slots[1];
|
|
atomic_inc(&leaf->refs);
|
|
/*
|
|
* We want to be able to at least push one item to the
|
|
* left neighbour leaf, and that's the first item.
|
|
*/
|
|
min_push_space = sizeof(struct btrfs_item) +
|
|
btrfs_item_size(leaf, 0);
|
|
wret = push_leaf_left(trans, root, path, 0,
|
|
min_push_space, 1, (u32)-1);
|
|
if (wret < 0 && wret != -ENOSPC)
|
|
ret = wret;
|
|
|
|
if (path->nodes[0] == leaf &&
|
|
btrfs_header_nritems(leaf)) {
|
|
/*
|
|
* If we were not able to push all items from our
|
|
* leaf to its left neighbour, then attempt to
|
|
* either push all the remaining items to the
|
|
* right neighbour or none. There's no advantage
|
|
* in pushing only some items, instead of all, as
|
|
* it's pointless to end up with a leaf having
|
|
* too few items while the neighbours can be full
|
|
* or nearly full.
|
|
*/
|
|
nritems = btrfs_header_nritems(leaf);
|
|
min_push_space = leaf_space_used(leaf, 0, nritems);
|
|
wret = push_leaf_right(trans, root, path, 0,
|
|
min_push_space, 1, 0);
|
|
if (wret < 0 && wret != -ENOSPC)
|
|
ret = wret;
|
|
}
|
|
|
|
if (btrfs_header_nritems(leaf) == 0) {
|
|
path->slots[1] = slot;
|
|
btrfs_del_leaf(trans, root, path, leaf);
|
|
free_extent_buffer(leaf);
|
|
ret = 0;
|
|
} else {
|
|
/* if we're still in the path, make sure
|
|
* we're dirty. Otherwise, one of the
|
|
* push_leaf functions must have already
|
|
* dirtied this buffer
|
|
*/
|
|
if (path->nodes[0] == leaf)
|
|
btrfs_mark_buffer_dirty(leaf);
|
|
free_extent_buffer(leaf);
|
|
}
|
|
} else {
|
|
btrfs_mark_buffer_dirty(leaf);
|
|
}
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* search the tree again to find a leaf with lesser keys
|
|
* returns 0 if it found something or 1 if there are no lesser leaves.
|
|
* returns < 0 on io errors.
|
|
*
|
|
* This may release the path, and so you may lose any locks held at the
|
|
* time you call it.
|
|
*/
|
|
int btrfs_prev_leaf(struct btrfs_root *root, struct btrfs_path *path)
|
|
{
|
|
struct btrfs_key key;
|
|
struct btrfs_disk_key found_key;
|
|
int ret;
|
|
|
|
btrfs_item_key_to_cpu(path->nodes[0], &key, 0);
|
|
|
|
if (key.offset > 0) {
|
|
key.offset--;
|
|
} else if (key.type > 0) {
|
|
key.type--;
|
|
key.offset = (u64)-1;
|
|
} else if (key.objectid > 0) {
|
|
key.objectid--;
|
|
key.type = (u8)-1;
|
|
key.offset = (u64)-1;
|
|
} else {
|
|
return 1;
|
|
}
|
|
|
|
btrfs_release_path(path);
|
|
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
|
|
if (ret < 0)
|
|
return ret;
|
|
btrfs_item_key(path->nodes[0], &found_key, 0);
|
|
ret = comp_keys(&found_key, &key);
|
|
/*
|
|
* We might have had an item with the previous key in the tree right
|
|
* before we released our path. And after we released our path, that
|
|
* item might have been pushed to the first slot (0) of the leaf we
|
|
* were holding due to a tree balance. Alternatively, an item with the
|
|
* previous key can exist as the only element of a leaf (big fat item).
|
|
* Therefore account for these 2 cases, so that our callers (like
|
|
* btrfs_previous_item) don't miss an existing item with a key matching
|
|
* the previous key we computed above.
|
|
*/
|
|
if (ret <= 0)
|
|
return 0;
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* A helper function to walk down the tree starting at min_key, and looking
|
|
* for nodes or leaves that are have a minimum transaction id.
|
|
* This is used by the btree defrag code, and tree logging
|
|
*
|
|
* This does not cow, but it does stuff the starting key it finds back
|
|
* into min_key, so you can call btrfs_search_slot with cow=1 on the
|
|
* key and get a writable path.
|
|
*
|
|
* This honors path->lowest_level to prevent descent past a given level
|
|
* of the tree.
|
|
*
|
|
* min_trans indicates the oldest transaction that you are interested
|
|
* in walking through. Any nodes or leaves older than min_trans are
|
|
* skipped over (without reading them).
|
|
*
|
|
* returns zero if something useful was found, < 0 on error and 1 if there
|
|
* was nothing in the tree that matched the search criteria.
|
|
*/
|
|
int btrfs_search_forward(struct btrfs_root *root, struct btrfs_key *min_key,
|
|
struct btrfs_path *path,
|
|
u64 min_trans)
|
|
{
|
|
struct extent_buffer *cur;
|
|
struct btrfs_key found_key;
|
|
int slot;
|
|
int sret;
|
|
u32 nritems;
|
|
int level;
|
|
int ret = 1;
|
|
int keep_locks = path->keep_locks;
|
|
|
|
ASSERT(!path->nowait);
|
|
path->keep_locks = 1;
|
|
again:
|
|
cur = btrfs_read_lock_root_node(root);
|
|
level = btrfs_header_level(cur);
|
|
WARN_ON(path->nodes[level]);
|
|
path->nodes[level] = cur;
|
|
path->locks[level] = BTRFS_READ_LOCK;
|
|
|
|
if (btrfs_header_generation(cur) < min_trans) {
|
|
ret = 1;
|
|
goto out;
|
|
}
|
|
while (1) {
|
|
nritems = btrfs_header_nritems(cur);
|
|
level = btrfs_header_level(cur);
|
|
sret = btrfs_bin_search(cur, min_key, &slot);
|
|
if (sret < 0) {
|
|
ret = sret;
|
|
goto out;
|
|
}
|
|
|
|
/* at the lowest level, we're done, setup the path and exit */
|
|
if (level == path->lowest_level) {
|
|
if (slot >= nritems)
|
|
goto find_next_key;
|
|
ret = 0;
|
|
path->slots[level] = slot;
|
|
btrfs_item_key_to_cpu(cur, &found_key, slot);
|
|
goto out;
|
|
}
|
|
if (sret && slot > 0)
|
|
slot--;
|
|
/*
|
|
* check this node pointer against the min_trans parameters.
|
|
* If it is too old, skip to the next one.
|
|
*/
|
|
while (slot < nritems) {
|
|
u64 gen;
|
|
|
|
gen = btrfs_node_ptr_generation(cur, slot);
|
|
if (gen < min_trans) {
|
|
slot++;
|
|
continue;
|
|
}
|
|
break;
|
|
}
|
|
find_next_key:
|
|
/*
|
|
* we didn't find a candidate key in this node, walk forward
|
|
* and find another one
|
|
*/
|
|
if (slot >= nritems) {
|
|
path->slots[level] = slot;
|
|
sret = btrfs_find_next_key(root, path, min_key, level,
|
|
min_trans);
|
|
if (sret == 0) {
|
|
btrfs_release_path(path);
|
|
goto again;
|
|
} else {
|
|
goto out;
|
|
}
|
|
}
|
|
/* save our key for returning back */
|
|
btrfs_node_key_to_cpu(cur, &found_key, slot);
|
|
path->slots[level] = slot;
|
|
if (level == path->lowest_level) {
|
|
ret = 0;
|
|
goto out;
|
|
}
|
|
cur = btrfs_read_node_slot(cur, slot);
|
|
if (IS_ERR(cur)) {
|
|
ret = PTR_ERR(cur);
|
|
goto out;
|
|
}
|
|
|
|
btrfs_tree_read_lock(cur);
|
|
|
|
path->locks[level - 1] = BTRFS_READ_LOCK;
|
|
path->nodes[level - 1] = cur;
|
|
unlock_up(path, level, 1, 0, NULL);
|
|
}
|
|
out:
|
|
path->keep_locks = keep_locks;
|
|
if (ret == 0) {
|
|
btrfs_unlock_up_safe(path, path->lowest_level + 1);
|
|
memcpy(min_key, &found_key, sizeof(found_key));
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* this is similar to btrfs_next_leaf, but does not try to preserve
|
|
* and fixup the path. It looks for and returns the next key in the
|
|
* tree based on the current path and the min_trans parameters.
|
|
*
|
|
* 0 is returned if another key is found, < 0 if there are any errors
|
|
* and 1 is returned if there are no higher keys in the tree
|
|
*
|
|
* path->keep_locks should be set to 1 on the search made before
|
|
* calling this function.
|
|
*/
|
|
int btrfs_find_next_key(struct btrfs_root *root, struct btrfs_path *path,
|
|
struct btrfs_key *key, int level, u64 min_trans)
|
|
{
|
|
int slot;
|
|
struct extent_buffer *c;
|
|
|
|
WARN_ON(!path->keep_locks && !path->skip_locking);
|
|
while (level < BTRFS_MAX_LEVEL) {
|
|
if (!path->nodes[level])
|
|
return 1;
|
|
|
|
slot = path->slots[level] + 1;
|
|
c = path->nodes[level];
|
|
next:
|
|
if (slot >= btrfs_header_nritems(c)) {
|
|
int ret;
|
|
int orig_lowest;
|
|
struct btrfs_key cur_key;
|
|
if (level + 1 >= BTRFS_MAX_LEVEL ||
|
|
!path->nodes[level + 1])
|
|
return 1;
|
|
|
|
if (path->locks[level + 1] || path->skip_locking) {
|
|
level++;
|
|
continue;
|
|
}
|
|
|
|
slot = btrfs_header_nritems(c) - 1;
|
|
if (level == 0)
|
|
btrfs_item_key_to_cpu(c, &cur_key, slot);
|
|
else
|
|
btrfs_node_key_to_cpu(c, &cur_key, slot);
|
|
|
|
orig_lowest = path->lowest_level;
|
|
btrfs_release_path(path);
|
|
path->lowest_level = level;
|
|
ret = btrfs_search_slot(NULL, root, &cur_key, path,
|
|
0, 0);
|
|
path->lowest_level = orig_lowest;
|
|
if (ret < 0)
|
|
return ret;
|
|
|
|
c = path->nodes[level];
|
|
slot = path->slots[level];
|
|
if (ret == 0)
|
|
slot++;
|
|
goto next;
|
|
}
|
|
|
|
if (level == 0)
|
|
btrfs_item_key_to_cpu(c, key, slot);
|
|
else {
|
|
u64 gen = btrfs_node_ptr_generation(c, slot);
|
|
|
|
if (gen < min_trans) {
|
|
slot++;
|
|
goto next;
|
|
}
|
|
btrfs_node_key_to_cpu(c, key, slot);
|
|
}
|
|
return 0;
|
|
}
|
|
return 1;
|
|
}
|
|
|
|
int btrfs_next_old_leaf(struct btrfs_root *root, struct btrfs_path *path,
|
|
u64 time_seq)
|
|
{
|
|
int slot;
|
|
int level;
|
|
struct extent_buffer *c;
|
|
struct extent_buffer *next;
|
|
struct btrfs_fs_info *fs_info = root->fs_info;
|
|
struct btrfs_key key;
|
|
bool need_commit_sem = false;
|
|
u32 nritems;
|
|
int ret;
|
|
int i;
|
|
|
|
/*
|
|
* The nowait semantics are used only for write paths, where we don't
|
|
* use the tree mod log and sequence numbers.
|
|
*/
|
|
if (time_seq)
|
|
ASSERT(!path->nowait);
|
|
|
|
nritems = btrfs_header_nritems(path->nodes[0]);
|
|
if (nritems == 0)
|
|
return 1;
|
|
|
|
btrfs_item_key_to_cpu(path->nodes[0], &key, nritems - 1);
|
|
again:
|
|
level = 1;
|
|
next = NULL;
|
|
btrfs_release_path(path);
|
|
|
|
path->keep_locks = 1;
|
|
|
|
if (time_seq) {
|
|
ret = btrfs_search_old_slot(root, &key, path, time_seq);
|
|
} else {
|
|
if (path->need_commit_sem) {
|
|
path->need_commit_sem = 0;
|
|
need_commit_sem = true;
|
|
if (path->nowait) {
|
|
if (!down_read_trylock(&fs_info->commit_root_sem)) {
|
|
ret = -EAGAIN;
|
|
goto done;
|
|
}
|
|
} else {
|
|
down_read(&fs_info->commit_root_sem);
|
|
}
|
|
}
|
|
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
|
|
}
|
|
path->keep_locks = 0;
|
|
|
|
if (ret < 0)
|
|
goto done;
|
|
|
|
nritems = btrfs_header_nritems(path->nodes[0]);
|
|
/*
|
|
* by releasing the path above we dropped all our locks. A balance
|
|
* could have added more items next to the key that used to be
|
|
* at the very end of the block. So, check again here and
|
|
* advance the path if there are now more items available.
|
|
*/
|
|
if (nritems > 0 && path->slots[0] < nritems - 1) {
|
|
if (ret == 0)
|
|
path->slots[0]++;
|
|
ret = 0;
|
|
goto done;
|
|
}
|
|
/*
|
|
* So the above check misses one case:
|
|
* - after releasing the path above, someone has removed the item that
|
|
* used to be at the very end of the block, and balance between leafs
|
|
* gets another one with bigger key.offset to replace it.
|
|
*
|
|
* This one should be returned as well, or we can get leaf corruption
|
|
* later(esp. in __btrfs_drop_extents()).
|
|
*
|
|
* And a bit more explanation about this check,
|
|
* with ret > 0, the key isn't found, the path points to the slot
|
|
* where it should be inserted, so the path->slots[0] item must be the
|
|
* bigger one.
|
|
*/
|
|
if (nritems > 0 && ret > 0 && path->slots[0] == nritems - 1) {
|
|
ret = 0;
|
|
goto done;
|
|
}
|
|
|
|
while (level < BTRFS_MAX_LEVEL) {
|
|
if (!path->nodes[level]) {
|
|
ret = 1;
|
|
goto done;
|
|
}
|
|
|
|
slot = path->slots[level] + 1;
|
|
c = path->nodes[level];
|
|
if (slot >= btrfs_header_nritems(c)) {
|
|
level++;
|
|
if (level == BTRFS_MAX_LEVEL) {
|
|
ret = 1;
|
|
goto done;
|
|
}
|
|
continue;
|
|
}
|
|
|
|
|
|
/*
|
|
* Our current level is where we're going to start from, and to
|
|
* make sure lockdep doesn't complain we need to drop our locks
|
|
* and nodes from 0 to our current level.
|
|
*/
|
|
for (i = 0; i < level; i++) {
|
|
if (path->locks[level]) {
|
|
btrfs_tree_read_unlock(path->nodes[i]);
|
|
path->locks[i] = 0;
|
|
}
|
|
free_extent_buffer(path->nodes[i]);
|
|
path->nodes[i] = NULL;
|
|
}
|
|
|
|
next = c;
|
|
ret = read_block_for_search(root, path, &next, level,
|
|
slot, &key);
|
|
if (ret == -EAGAIN && !path->nowait)
|
|
goto again;
|
|
|
|
if (ret < 0) {
|
|
btrfs_release_path(path);
|
|
goto done;
|
|
}
|
|
|
|
if (!path->skip_locking) {
|
|
ret = btrfs_try_tree_read_lock(next);
|
|
if (!ret && path->nowait) {
|
|
ret = -EAGAIN;
|
|
goto done;
|
|
}
|
|
if (!ret && time_seq) {
|
|
/*
|
|
* If we don't get the lock, we may be racing
|
|
* with push_leaf_left, holding that lock while
|
|
* itself waiting for the leaf we've currently
|
|
* locked. To solve this situation, we give up
|
|
* on our lock and cycle.
|
|
*/
|
|
free_extent_buffer(next);
|
|
btrfs_release_path(path);
|
|
cond_resched();
|
|
goto again;
|
|
}
|
|
if (!ret)
|
|
btrfs_tree_read_lock(next);
|
|
}
|
|
break;
|
|
}
|
|
path->slots[level] = slot;
|
|
while (1) {
|
|
level--;
|
|
path->nodes[level] = next;
|
|
path->slots[level] = 0;
|
|
if (!path->skip_locking)
|
|
path->locks[level] = BTRFS_READ_LOCK;
|
|
if (!level)
|
|
break;
|
|
|
|
ret = read_block_for_search(root, path, &next, level,
|
|
0, &key);
|
|
if (ret == -EAGAIN && !path->nowait)
|
|
goto again;
|
|
|
|
if (ret < 0) {
|
|
btrfs_release_path(path);
|
|
goto done;
|
|
}
|
|
|
|
if (!path->skip_locking) {
|
|
if (path->nowait) {
|
|
if (!btrfs_try_tree_read_lock(next)) {
|
|
ret = -EAGAIN;
|
|
goto done;
|
|
}
|
|
} else {
|
|
btrfs_tree_read_lock(next);
|
|
}
|
|
}
|
|
}
|
|
ret = 0;
|
|
done:
|
|
unlock_up(path, 0, 1, 0, NULL);
|
|
if (need_commit_sem) {
|
|
int ret2;
|
|
|
|
path->need_commit_sem = 1;
|
|
ret2 = finish_need_commit_sem_search(path);
|
|
up_read(&fs_info->commit_root_sem);
|
|
if (ret2)
|
|
ret = ret2;
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
int btrfs_next_old_item(struct btrfs_root *root, struct btrfs_path *path, u64 time_seq)
|
|
{
|
|
path->slots[0]++;
|
|
if (path->slots[0] >= btrfs_header_nritems(path->nodes[0]))
|
|
return btrfs_next_old_leaf(root, path, time_seq);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* this uses btrfs_prev_leaf to walk backwards in the tree, and keeps
|
|
* searching until it gets past min_objectid or finds an item of 'type'
|
|
*
|
|
* returns 0 if something is found, 1 if nothing was found and < 0 on error
|
|
*/
|
|
int btrfs_previous_item(struct btrfs_root *root,
|
|
struct btrfs_path *path, u64 min_objectid,
|
|
int type)
|
|
{
|
|
struct btrfs_key found_key;
|
|
struct extent_buffer *leaf;
|
|
u32 nritems;
|
|
int ret;
|
|
|
|
while (1) {
|
|
if (path->slots[0] == 0) {
|
|
ret = btrfs_prev_leaf(root, path);
|
|
if (ret != 0)
|
|
return ret;
|
|
} else {
|
|
path->slots[0]--;
|
|
}
|
|
leaf = path->nodes[0];
|
|
nritems = btrfs_header_nritems(leaf);
|
|
if (nritems == 0)
|
|
return 1;
|
|
if (path->slots[0] == nritems)
|
|
path->slots[0]--;
|
|
|
|
btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
|
|
if (found_key.objectid < min_objectid)
|
|
break;
|
|
if (found_key.type == type)
|
|
return 0;
|
|
if (found_key.objectid == min_objectid &&
|
|
found_key.type < type)
|
|
break;
|
|
}
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* search in extent tree to find a previous Metadata/Data extent item with
|
|
* min objecitd.
|
|
*
|
|
* returns 0 if something is found, 1 if nothing was found and < 0 on error
|
|
*/
|
|
int btrfs_previous_extent_item(struct btrfs_root *root,
|
|
struct btrfs_path *path, u64 min_objectid)
|
|
{
|
|
struct btrfs_key found_key;
|
|
struct extent_buffer *leaf;
|
|
u32 nritems;
|
|
int ret;
|
|
|
|
while (1) {
|
|
if (path->slots[0] == 0) {
|
|
ret = btrfs_prev_leaf(root, path);
|
|
if (ret != 0)
|
|
return ret;
|
|
} else {
|
|
path->slots[0]--;
|
|
}
|
|
leaf = path->nodes[0];
|
|
nritems = btrfs_header_nritems(leaf);
|
|
if (nritems == 0)
|
|
return 1;
|
|
if (path->slots[0] == nritems)
|
|
path->slots[0]--;
|
|
|
|
btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
|
|
if (found_key.objectid < min_objectid)
|
|
break;
|
|
if (found_key.type == BTRFS_EXTENT_ITEM_KEY ||
|
|
found_key.type == BTRFS_METADATA_ITEM_KEY)
|
|
return 0;
|
|
if (found_key.objectid == min_objectid &&
|
|
found_key.type < BTRFS_EXTENT_ITEM_KEY)
|
|
break;
|
|
}
|
|
return 1;
|
|
}
|
|
|
|
int __init btrfs_ctree_init(void)
|
|
{
|
|
btrfs_path_cachep = kmem_cache_create("btrfs_path",
|
|
sizeof(struct btrfs_path), 0,
|
|
SLAB_MEM_SPREAD, NULL);
|
|
if (!btrfs_path_cachep)
|
|
return -ENOMEM;
|
|
return 0;
|
|
}
|
|
|
|
void __cold btrfs_ctree_exit(void)
|
|
{
|
|
kmem_cache_destroy(btrfs_path_cachep);
|
|
}
|