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linux/fs/btrfs/file.c
Filipe Manana 162d053e15 btrfs: do not BUG_ON() on ENOMEM when dropping extent items for a range 
If we get -ENOMEM while dropping file extent items in a given range, at
btrfs_drop_extents(), due to failure to allocate memory when attempting to
increment the reference count for an extent or drop the reference count,
we handle it with a BUG_ON(). This is excessive, instead we can simply
abort the transaction and return the error to the caller. In fact most
callers of btrfs_drop_extents(), directly or indirectly, already abort
the transaction if btrfs_drop_extents() returns any error.

Also, we already have error paths at btrfs_drop_extents() that may return
-ENOMEM and in those cases we abort the transaction, like for example
anything that changes the b+tree may return -ENOMEM due to a failure to
allocate a new extent buffer when COWing an existing extent buffer, such
as a call to btrfs_duplicate_item() for example.

So replace the BUG_ON() calls with proper logic to abort the transaction
and return the error.

Reported-by: syzbot+0b1fb6b0108c27419f9f@syzkaller.appspotmail.com
Link: https://lore.kernel.org/linux-btrfs/00000000000089773e05ee4b9cb4@google.com/
CC: stable@vger.kernel.org # 5.4+
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>
2022-12-05 18:00:59 +01:00

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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2007 Oracle. All rights reserved.
*/
#include <linux/fs.h>
#include <linux/pagemap.h>
#include <linux/time.h>
#include <linux/init.h>
#include <linux/string.h>
#include <linux/backing-dev.h>
#include <linux/falloc.h>
#include <linux/writeback.h>
#include <linux/compat.h>
#include <linux/slab.h>
#include <linux/btrfs.h>
#include <linux/uio.h>
#include <linux/iversion.h>
#include <linux/fsverity.h>
#include "ctree.h"
#include "disk-io.h"
#include "transaction.h"
#include "btrfs_inode.h"
#include "print-tree.h"
#include "tree-log.h"
#include "locking.h"
#include "volumes.h"
#include "qgroup.h"
#include "compression.h"
#include "delalloc-space.h"
#include "reflink.h"
#include "subpage.h"
#include "fs.h"
#include "accessors.h"
#include "extent-tree.h"
#include "file-item.h"
#include "ioctl.h"
#include "file.h"
#include "super.h"
/* simple helper to fault in pages and copy. This should go away
* and be replaced with calls into generic code.
*/
static noinline int btrfs_copy_from_user(loff_t pos, size_t write_bytes,
struct page **prepared_pages,
struct iov_iter *i)
{
size_t copied = 0;
size_t total_copied = 0;
int pg = 0;
int offset = offset_in_page(pos);
while (write_bytes > 0) {
size_t count = min_t(size_t,
PAGE_SIZE - offset, write_bytes);
struct page *page = prepared_pages[pg];
/*
* Copy data from userspace to the current page
*/
copied = copy_page_from_iter_atomic(page, offset, count, i);
/* Flush processor's dcache for this page */
flush_dcache_page(page);
/*
* if we get a partial write, we can end up with
* partially up to date pages. These add
* a lot of complexity, so make sure they don't
* happen by forcing this copy to be retried.
*
* The rest of the btrfs_file_write code will fall
* back to page at a time copies after we return 0.
*/
if (unlikely(copied < count)) {
if (!PageUptodate(page)) {
iov_iter_revert(i, copied);
copied = 0;
}
if (!copied)
break;
}
write_bytes -= copied;
total_copied += copied;
offset += copied;
if (offset == PAGE_SIZE) {
pg++;
offset = 0;
}
}
return total_copied;
}
/*
* unlocks pages after btrfs_file_write is done with them
*/
static void btrfs_drop_pages(struct btrfs_fs_info *fs_info,
struct page **pages, size_t num_pages,
u64 pos, u64 copied)
{
size_t i;
u64 block_start = round_down(pos, fs_info->sectorsize);
u64 block_len = round_up(pos + copied, fs_info->sectorsize) - block_start;
ASSERT(block_len <= U32_MAX);
for (i = 0; i < num_pages; i++) {
/* page checked is some magic around finding pages that
* have been modified without going through btrfs_set_page_dirty
* clear it here. There should be no need to mark the pages
* accessed as prepare_pages should have marked them accessed
* in prepare_pages via find_or_create_page()
*/
btrfs_page_clamp_clear_checked(fs_info, pages[i], block_start,
block_len);
unlock_page(pages[i]);
put_page(pages[i]);
}
}
/*
* After btrfs_copy_from_user(), update the following things for delalloc:
* - Mark newly dirtied pages as DELALLOC in the io tree.
* Used to advise which range is to be written back.
* - Mark modified pages as Uptodate/Dirty and not needing COW fixup
* - Update inode size for past EOF write
*/
int btrfs_dirty_pages(struct btrfs_inode *inode, struct page **pages,
size_t num_pages, loff_t pos, size_t write_bytes,
struct extent_state **cached, bool noreserve)
{
struct btrfs_fs_info *fs_info = inode->root->fs_info;
int err = 0;
int i;
u64 num_bytes;
u64 start_pos;
u64 end_of_last_block;
u64 end_pos = pos + write_bytes;
loff_t isize = i_size_read(&inode->vfs_inode);
unsigned int extra_bits = 0;
if (write_bytes == 0)
return 0;
if (noreserve)
extra_bits |= EXTENT_NORESERVE;
start_pos = round_down(pos, fs_info->sectorsize);
num_bytes = round_up(write_bytes + pos - start_pos,
fs_info->sectorsize);
ASSERT(num_bytes <= U32_MAX);
end_of_last_block = start_pos + num_bytes - 1;
/*
* The pages may have already been dirty, clear out old accounting so
* we can set things up properly
*/
clear_extent_bit(&inode->io_tree, start_pos, end_of_last_block,
EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG,
cached);
err = btrfs_set_extent_delalloc(inode, start_pos, end_of_last_block,
extra_bits, cached);
if (err)
return err;
for (i = 0; i < num_pages; i++) {
struct page *p = pages[i];
btrfs_page_clamp_set_uptodate(fs_info, p, start_pos, num_bytes);
btrfs_page_clamp_clear_checked(fs_info, p, start_pos, num_bytes);
btrfs_page_clamp_set_dirty(fs_info, p, start_pos, num_bytes);
}
/*
* we've only changed i_size in ram, and we haven't updated
* the disk i_size. There is no need to log the inode
* at this time.
*/
if (end_pos > isize)
i_size_write(&inode->vfs_inode, end_pos);
return 0;
}
/*
* this is very complex, but the basic idea is to drop all extents
* in the range start - end. hint_block is filled in with a block number
* that would be a good hint to the block allocator for this file.
*
* If an extent intersects the range but is not entirely inside the range
* it is either truncated or split. Anything entirely inside the range
* is deleted from the tree.
*
* Note: the VFS' inode number of bytes is not updated, it's up to the caller
* to deal with that. We set the field 'bytes_found' of the arguments structure
* with the number of allocated bytes found in the target range, so that the
* caller can update the inode's number of bytes in an atomic way when
* replacing extents in a range to avoid races with stat(2).
*/
int btrfs_drop_extents(struct btrfs_trans_handle *trans,
struct btrfs_root *root, struct btrfs_inode *inode,
struct btrfs_drop_extents_args *args)
{
struct btrfs_fs_info *fs_info = root->fs_info;
struct extent_buffer *leaf;
struct btrfs_file_extent_item *fi;
struct btrfs_ref ref = { 0 };
struct btrfs_key key;
struct btrfs_key new_key;
u64 ino = btrfs_ino(inode);
u64 search_start = args->start;
u64 disk_bytenr = 0;
u64 num_bytes = 0;
u64 extent_offset = 0;
u64 extent_end = 0;
u64 last_end = args->start;
int del_nr = 0;
int del_slot = 0;
int extent_type;
int recow;
int ret;
int modify_tree = -1;
int update_refs;
int found = 0;
struct btrfs_path *path = args->path;
args->bytes_found = 0;
args->extent_inserted = false;
/* Must always have a path if ->replace_extent is true */
ASSERT(!(args->replace_extent && !args->path));
if (!path) {
path = btrfs_alloc_path();
if (!path) {
ret = -ENOMEM;
goto out;
}
}
if (args->drop_cache)
btrfs_drop_extent_map_range(inode, args->start, args->end - 1, false);
if (args->start >= inode->disk_i_size && !args->replace_extent)
modify_tree = 0;
update_refs = (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID);
while (1) {
recow = 0;
ret = btrfs_lookup_file_extent(trans, root, path, ino,
search_start, modify_tree);
if (ret < 0)
break;
if (ret > 0 && path->slots[0] > 0 && search_start == args->start) {
leaf = path->nodes[0];
btrfs_item_key_to_cpu(leaf, &key, path->slots[0] - 1);
if (key.objectid == ino &&
key.type == BTRFS_EXTENT_DATA_KEY)
path->slots[0]--;
}
ret = 0;
next_slot:
leaf = path->nodes[0];
if (path->slots[0] >= btrfs_header_nritems(leaf)) {
BUG_ON(del_nr > 0);
ret = btrfs_next_leaf(root, path);
if (ret < 0)
break;
if (ret > 0) {
ret = 0;
break;
}
leaf = path->nodes[0];
recow = 1;
}
btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
if (key.objectid > ino)
break;
if (WARN_ON_ONCE(key.objectid < ino) ||
key.type < BTRFS_EXTENT_DATA_KEY) {
ASSERT(del_nr == 0);
path->slots[0]++;
goto next_slot;
}
if (key.type > BTRFS_EXTENT_DATA_KEY || key.offset >= args->end)
break;
fi = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_file_extent_item);
extent_type = btrfs_file_extent_type(leaf, fi);
if (extent_type == BTRFS_FILE_EXTENT_REG ||
extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
extent_offset = btrfs_file_extent_offset(leaf, fi);
extent_end = key.offset +
btrfs_file_extent_num_bytes(leaf, fi);
} else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
extent_end = key.offset +
btrfs_file_extent_ram_bytes(leaf, fi);
} else {
/* can't happen */
BUG();
}
/*
* Don't skip extent items representing 0 byte lengths. They
* used to be created (bug) if while punching holes we hit
* -ENOSPC condition. So if we find one here, just ensure we
* delete it, otherwise we would insert a new file extent item
* with the same key (offset) as that 0 bytes length file
* extent item in the call to setup_items_for_insert() later
* in this function.
*/
if (extent_end == key.offset && extent_end >= search_start) {
last_end = extent_end;
goto delete_extent_item;
}
if (extent_end <= search_start) {
path->slots[0]++;
goto next_slot;
}
found = 1;
search_start = max(key.offset, args->start);
if (recow || !modify_tree) {
modify_tree = -1;
btrfs_release_path(path);
continue;
}
/*
* | - range to drop - |
* | -------- extent -------- |
*/
if (args->start > key.offset && args->end < extent_end) {
BUG_ON(del_nr > 0);
if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
ret = -EOPNOTSUPP;
break;
}
memcpy(&new_key, &key, sizeof(new_key));
new_key.offset = args->start;
ret = btrfs_duplicate_item(trans, root, path,
&new_key);
if (ret == -EAGAIN) {
btrfs_release_path(path);
continue;
}
if (ret < 0)
break;
leaf = path->nodes[0];
fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
struct btrfs_file_extent_item);
btrfs_set_file_extent_num_bytes(leaf, fi,
args->start - key.offset);
fi = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_file_extent_item);
extent_offset += args->start - key.offset;
btrfs_set_file_extent_offset(leaf, fi, extent_offset);
btrfs_set_file_extent_num_bytes(leaf, fi,
extent_end - args->start);
btrfs_mark_buffer_dirty(leaf);
if (update_refs && disk_bytenr > 0) {
btrfs_init_generic_ref(&ref,
BTRFS_ADD_DELAYED_REF,
disk_bytenr, num_bytes, 0);
btrfs_init_data_ref(&ref,
root->root_key.objectid,
new_key.objectid,
args->start - extent_offset,
0, false);
ret = btrfs_inc_extent_ref(trans, &ref);
if (ret) {
btrfs_abort_transaction(trans, ret);
break;
}
}
key.offset = args->start;
}
/*
* From here on out we will have actually dropped something, so
* last_end can be updated.
*/
last_end = extent_end;
/*
* | ---- range to drop ----- |
* | -------- extent -------- |
*/
if (args->start <= key.offset && args->end < extent_end) {
if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
ret = -EOPNOTSUPP;
break;
}
memcpy(&new_key, &key, sizeof(new_key));
new_key.offset = args->end;
btrfs_set_item_key_safe(fs_info, path, &new_key);
extent_offset += args->end - key.offset;
btrfs_set_file_extent_offset(leaf, fi, extent_offset);
btrfs_set_file_extent_num_bytes(leaf, fi,
extent_end - args->end);
btrfs_mark_buffer_dirty(leaf);
if (update_refs && disk_bytenr > 0)
args->bytes_found += args->end - key.offset;
break;
}
search_start = extent_end;
/*
* | ---- range to drop ----- |
* | -------- extent -------- |
*/
if (args->start > key.offset && args->end >= extent_end) {
BUG_ON(del_nr > 0);
if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
ret = -EOPNOTSUPP;
break;
}
btrfs_set_file_extent_num_bytes(leaf, fi,
args->start - key.offset);
btrfs_mark_buffer_dirty(leaf);
if (update_refs && disk_bytenr > 0)
args->bytes_found += extent_end - args->start;
if (args->end == extent_end)
break;
path->slots[0]++;
goto next_slot;
}
/*
* | ---- range to drop ----- |
* | ------ extent ------ |
*/
if (args->start <= key.offset && args->end >= extent_end) {
delete_extent_item:
if (del_nr == 0) {
del_slot = path->slots[0];
del_nr = 1;
} else {
BUG_ON(del_slot + del_nr != path->slots[0]);
del_nr++;
}
if (update_refs &&
extent_type == BTRFS_FILE_EXTENT_INLINE) {
args->bytes_found += extent_end - key.offset;
extent_end = ALIGN(extent_end,
fs_info->sectorsize);
} else if (update_refs && disk_bytenr > 0) {
btrfs_init_generic_ref(&ref,
BTRFS_DROP_DELAYED_REF,
disk_bytenr, num_bytes, 0);
btrfs_init_data_ref(&ref,
root->root_key.objectid,
key.objectid,
key.offset - extent_offset, 0,
false);
ret = btrfs_free_extent(trans, &ref);
if (ret) {
btrfs_abort_transaction(trans, ret);
break;
}
args->bytes_found += extent_end - key.offset;
}
if (args->end == extent_end)
break;
if (path->slots[0] + 1 < btrfs_header_nritems(leaf)) {
path->slots[0]++;
goto next_slot;
}
ret = btrfs_del_items(trans, root, path, del_slot,
del_nr);
if (ret) {
btrfs_abort_transaction(trans, ret);
break;
}
del_nr = 0;
del_slot = 0;
btrfs_release_path(path);
continue;
}
BUG();
}
if (!ret && del_nr > 0) {
/*
* Set path->slots[0] to first slot, so that after the delete
* if items are move off from our leaf to its immediate left or
* right neighbor leafs, we end up with a correct and adjusted
* path->slots[0] for our insertion (if args->replace_extent).
*/
path->slots[0] = del_slot;
ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
if (ret)
btrfs_abort_transaction(trans, ret);
}
leaf = path->nodes[0];
/*
* If btrfs_del_items() was called, it might have deleted a leaf, in
* which case it unlocked our path, so check path->locks[0] matches a
* write lock.
*/
if (!ret && args->replace_extent &&
path->locks[0] == BTRFS_WRITE_LOCK &&
btrfs_leaf_free_space(leaf) >=
sizeof(struct btrfs_item) + args->extent_item_size) {
key.objectid = ino;
key.type = BTRFS_EXTENT_DATA_KEY;
key.offset = args->start;
if (!del_nr && path->slots[0] < btrfs_header_nritems(leaf)) {
struct btrfs_key slot_key;
btrfs_item_key_to_cpu(leaf, &slot_key, path->slots[0]);
if (btrfs_comp_cpu_keys(&key, &slot_key) > 0)
path->slots[0]++;
}
btrfs_setup_item_for_insert(root, path, &key, args->extent_item_size);
args->extent_inserted = true;
}
if (!args->path)
btrfs_free_path(path);
else if (!args->extent_inserted)
btrfs_release_path(path);
out:
args->drop_end = found ? min(args->end, last_end) : args->end;
return ret;
}
static int extent_mergeable(struct extent_buffer *leaf, int slot,
u64 objectid, u64 bytenr, u64 orig_offset,
u64 *start, u64 *end)
{
struct btrfs_file_extent_item *fi;
struct btrfs_key key;
u64 extent_end;
if (slot < 0 || slot >= btrfs_header_nritems(leaf))
return 0;
btrfs_item_key_to_cpu(leaf, &key, slot);
if (key.objectid != objectid || key.type != BTRFS_EXTENT_DATA_KEY)
return 0;
fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG ||
btrfs_file_extent_disk_bytenr(leaf, fi) != bytenr ||
btrfs_file_extent_offset(leaf, fi) != key.offset - orig_offset ||
btrfs_file_extent_compression(leaf, fi) ||
btrfs_file_extent_encryption(leaf, fi) ||
btrfs_file_extent_other_encoding(leaf, fi))
return 0;
extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
if ((*start && *start != key.offset) || (*end && *end != extent_end))
return 0;
*start = key.offset;
*end = extent_end;
return 1;
}
/*
* Mark extent in the range start - end as written.
*
* This changes extent type from 'pre-allocated' to 'regular'. If only
* part of extent is marked as written, the extent will be split into
* two or three.
*/
int btrfs_mark_extent_written(struct btrfs_trans_handle *trans,
struct btrfs_inode *inode, u64 start, u64 end)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_root *root = inode->root;
struct extent_buffer *leaf;
struct btrfs_path *path;
struct btrfs_file_extent_item *fi;
struct btrfs_ref ref = { 0 };
struct btrfs_key key;
struct btrfs_key new_key;
u64 bytenr;
u64 num_bytes;
u64 extent_end;
u64 orig_offset;
u64 other_start;
u64 other_end;
u64 split;
int del_nr = 0;
int del_slot = 0;
int recow;
int ret = 0;
u64 ino = btrfs_ino(inode);
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
again:
recow = 0;
split = start;
key.objectid = ino;
key.type = BTRFS_EXTENT_DATA_KEY;
key.offset = split;
ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
if (ret < 0)
goto out;
if (ret > 0 && path->slots[0] > 0)
path->slots[0]--;
leaf = path->nodes[0];
btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
if (key.objectid != ino ||
key.type != BTRFS_EXTENT_DATA_KEY) {
ret = -EINVAL;
btrfs_abort_transaction(trans, ret);
goto out;
}
fi = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_file_extent_item);
if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_PREALLOC) {
ret = -EINVAL;
btrfs_abort_transaction(trans, ret);
goto out;
}
extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
if (key.offset > start || extent_end < end) {
ret = -EINVAL;
btrfs_abort_transaction(trans, ret);
goto out;
}
bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
orig_offset = key.offset - btrfs_file_extent_offset(leaf, fi);
memcpy(&new_key, &key, sizeof(new_key));
if (start == key.offset && end < extent_end) {
other_start = 0;
other_end = start;
if (extent_mergeable(leaf, path->slots[0] - 1,
ino, bytenr, orig_offset,
&other_start, &other_end)) {
new_key.offset = end;
btrfs_set_item_key_safe(fs_info, path, &new_key);
fi = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_file_extent_item);
btrfs_set_file_extent_generation(leaf, fi,
trans->transid);
btrfs_set_file_extent_num_bytes(leaf, fi,
extent_end - end);
btrfs_set_file_extent_offset(leaf, fi,
end - orig_offset);
fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
struct btrfs_file_extent_item);
btrfs_set_file_extent_generation(leaf, fi,
trans->transid);
btrfs_set_file_extent_num_bytes(leaf, fi,
end - other_start);
btrfs_mark_buffer_dirty(leaf);
goto out;
}
}
if (start > key.offset && end == extent_end) {
other_start = end;
other_end = 0;
if (extent_mergeable(leaf, path->slots[0] + 1,
ino, bytenr, orig_offset,
&other_start, &other_end)) {
fi = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_file_extent_item);
btrfs_set_file_extent_num_bytes(leaf, fi,
start - key.offset);
btrfs_set_file_extent_generation(leaf, fi,
trans->transid);
path->slots[0]++;
new_key.offset = start;
btrfs_set_item_key_safe(fs_info, path, &new_key);
fi = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_file_extent_item);
btrfs_set_file_extent_generation(leaf, fi,
trans->transid);
btrfs_set_file_extent_num_bytes(leaf, fi,
other_end - start);
btrfs_set_file_extent_offset(leaf, fi,
start - orig_offset);
btrfs_mark_buffer_dirty(leaf);
goto out;
}
}
while (start > key.offset || end < extent_end) {
if (key.offset == start)
split = end;
new_key.offset = split;
ret = btrfs_duplicate_item(trans, root, path, &new_key);
if (ret == -EAGAIN) {
btrfs_release_path(path);
goto again;
}
if (ret < 0) {
btrfs_abort_transaction(trans, ret);
goto out;
}
leaf = path->nodes[0];
fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
struct btrfs_file_extent_item);
btrfs_set_file_extent_generation(leaf, fi, trans->transid);
btrfs_set_file_extent_num_bytes(leaf, fi,
split - key.offset);
fi = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_file_extent_item);
btrfs_set_file_extent_generation(leaf, fi, trans->transid);
btrfs_set_file_extent_offset(leaf, fi, split - orig_offset);
btrfs_set_file_extent_num_bytes(leaf, fi,
extent_end - split);
btrfs_mark_buffer_dirty(leaf);
btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF, bytenr,
num_bytes, 0);
btrfs_init_data_ref(&ref, root->root_key.objectid, ino,
orig_offset, 0, false);
ret = btrfs_inc_extent_ref(trans, &ref);
if (ret) {
btrfs_abort_transaction(trans, ret);
goto out;
}
if (split == start) {
key.offset = start;
} else {
if (start != key.offset) {
ret = -EINVAL;
btrfs_abort_transaction(trans, ret);
goto out;
}
path->slots[0]--;
extent_end = end;
}
recow = 1;
}
other_start = end;
other_end = 0;
btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, bytenr,
num_bytes, 0);
btrfs_init_data_ref(&ref, root->root_key.objectid, ino, orig_offset,
0, false);
if (extent_mergeable(leaf, path->slots[0] + 1,
ino, bytenr, orig_offset,
&other_start, &other_end)) {
if (recow) {
btrfs_release_path(path);
goto again;
}
extent_end = other_end;
del_slot = path->slots[0] + 1;
del_nr++;
ret = btrfs_free_extent(trans, &ref);
if (ret) {
btrfs_abort_transaction(trans, ret);
goto out;
}
}
other_start = 0;
other_end = start;
if (extent_mergeable(leaf, path->slots[0] - 1,
ino, bytenr, orig_offset,
&other_start, &other_end)) {
if (recow) {
btrfs_release_path(path);
goto again;
}
key.offset = other_start;
del_slot = path->slots[0];
del_nr++;
ret = btrfs_free_extent(trans, &ref);
if (ret) {
btrfs_abort_transaction(trans, ret);
goto out;
}
}
if (del_nr == 0) {
fi = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_file_extent_item);
btrfs_set_file_extent_type(leaf, fi,
BTRFS_FILE_EXTENT_REG);
btrfs_set_file_extent_generation(leaf, fi, trans->transid);
btrfs_mark_buffer_dirty(leaf);
} else {
fi = btrfs_item_ptr(leaf, del_slot - 1,
struct btrfs_file_extent_item);
btrfs_set_file_extent_type(leaf, fi,
BTRFS_FILE_EXTENT_REG);
btrfs_set_file_extent_generation(leaf, fi, trans->transid);
btrfs_set_file_extent_num_bytes(leaf, fi,
extent_end - key.offset);
btrfs_mark_buffer_dirty(leaf);
ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
if (ret < 0) {
btrfs_abort_transaction(trans, ret);
goto out;
}
}
out:
btrfs_free_path(path);
return ret;
}
/*
* on error we return an unlocked page and the error value
* on success we return a locked page and 0
*/
static int prepare_uptodate_page(struct inode *inode,
struct page *page, u64 pos,
bool force_uptodate)
{
struct folio *folio = page_folio(page);
int ret = 0;
if (((pos & (PAGE_SIZE - 1)) || force_uptodate) &&
!PageUptodate(page)) {
ret = btrfs_read_folio(NULL, folio);
if (ret)
return ret;
lock_page(page);
if (!PageUptodate(page)) {
unlock_page(page);
return -EIO;
}
/*
* Since btrfs_read_folio() will unlock the folio before it
* returns, there is a window where btrfs_release_folio() can be
* called to release the page. Here we check both inode
* mapping and PagePrivate() to make sure the page was not
* released.
*
* The private flag check is essential for subpage as we need
* to store extra bitmap using page->private.
*/
if (page->mapping != inode->i_mapping || !PagePrivate(page)) {
unlock_page(page);
return -EAGAIN;
}
}
return 0;
}
static unsigned int get_prepare_fgp_flags(bool nowait)
{
unsigned int fgp_flags = FGP_LOCK | FGP_ACCESSED | FGP_CREAT;
if (nowait)
fgp_flags |= FGP_NOWAIT;
return fgp_flags;
}
static gfp_t get_prepare_gfp_flags(struct inode *inode, bool nowait)
{
gfp_t gfp;
gfp = btrfs_alloc_write_mask(inode->i_mapping);
if (nowait) {
gfp &= ~__GFP_DIRECT_RECLAIM;
gfp |= GFP_NOWAIT;
}
return gfp;
}
/*
* this just gets pages into the page cache and locks them down.
*/
static noinline int prepare_pages(struct inode *inode, struct page **pages,
size_t num_pages, loff_t pos,
size_t write_bytes, bool force_uptodate,
bool nowait)
{
int i;
unsigned long index = pos >> PAGE_SHIFT;
gfp_t mask = get_prepare_gfp_flags(inode, nowait);
unsigned int fgp_flags = get_prepare_fgp_flags(nowait);
int err = 0;
int faili;
for (i = 0; i < num_pages; i++) {
again:
pages[i] = pagecache_get_page(inode->i_mapping, index + i,
fgp_flags, mask | __GFP_WRITE);
if (!pages[i]) {
faili = i - 1;
if (nowait)
err = -EAGAIN;
else
err = -ENOMEM;
goto fail;
}
err = set_page_extent_mapped(pages[i]);
if (err < 0) {
faili = i;
goto fail;
}
if (i == 0)
err = prepare_uptodate_page(inode, pages[i], pos,
force_uptodate);
if (!err && i == num_pages - 1)
err = prepare_uptodate_page(inode, pages[i],
pos + write_bytes, false);
if (err) {
put_page(pages[i]);
if (!nowait && err == -EAGAIN) {
err = 0;
goto again;
}
faili = i - 1;
goto fail;
}
wait_on_page_writeback(pages[i]);
}
return 0;
fail:
while (faili >= 0) {
unlock_page(pages[faili]);
put_page(pages[faili]);
faili--;
}
return err;
}
/*
* This function locks the extent and properly waits for data=ordered extents
* to finish before allowing the pages to be modified if need.
*
* The return value:
* 1 - the extent is locked
* 0 - the extent is not locked, and everything is OK
* -EAGAIN - need re-prepare the pages
* the other < 0 number - Something wrong happens
*/
static noinline int
lock_and_cleanup_extent_if_need(struct btrfs_inode *inode, struct page **pages,
size_t num_pages, loff_t pos,
size_t write_bytes,
u64 *lockstart, u64 *lockend, bool nowait,
struct extent_state **cached_state)
{
struct btrfs_fs_info *fs_info = inode->root->fs_info;
u64 start_pos;
u64 last_pos;
int i;
int ret = 0;
start_pos = round_down(pos, fs_info->sectorsize);
last_pos = round_up(pos + write_bytes, fs_info->sectorsize) - 1;
if (start_pos < inode->vfs_inode.i_size) {
struct btrfs_ordered_extent *ordered;
if (nowait) {
if (!try_lock_extent(&inode->io_tree, start_pos, last_pos,
cached_state)) {
for (i = 0; i < num_pages; i++) {
unlock_page(pages[i]);
put_page(pages[i]);
pages[i] = NULL;
}
return -EAGAIN;
}
} else {
lock_extent(&inode->io_tree, start_pos, last_pos, cached_state);
}
ordered = btrfs_lookup_ordered_range(inode, start_pos,
last_pos - start_pos + 1);
if (ordered &&
ordered->file_offset + ordered->num_bytes > start_pos &&
ordered->file_offset <= last_pos) {
unlock_extent(&inode->io_tree, start_pos, last_pos,
cached_state);
for (i = 0; i < num_pages; i++) {
unlock_page(pages[i]);
put_page(pages[i]);
}
btrfs_start_ordered_extent(ordered, 1);
btrfs_put_ordered_extent(ordered);
return -EAGAIN;
}
if (ordered)
btrfs_put_ordered_extent(ordered);
*lockstart = start_pos;
*lockend = last_pos;
ret = 1;
}
/*
* We should be called after prepare_pages() which should have locked
* all pages in the range.
*/
for (i = 0; i < num_pages; i++)
WARN_ON(!PageLocked(pages[i]));
return ret;
}
/*
* Check if we can do nocow write into the range [@pos, @pos + @write_bytes)
*
* @pos: File offset.
* @write_bytes: The length to write, will be updated to the nocow writeable
* range.
*
* This function will flush ordered extents in the range to ensure proper
* nocow checks.
*
* Return:
* > 0 If we can nocow, and updates @write_bytes.
* 0 If we can't do a nocow write.
* -EAGAIN If we can't do a nocow write because snapshoting of the inode's
* root is in progress.
* < 0 If an error happened.
*
* NOTE: Callers need to call btrfs_check_nocow_unlock() if we return > 0.
*/
int btrfs_check_nocow_lock(struct btrfs_inode *inode, loff_t pos,
size_t *write_bytes, bool nowait)
{
struct btrfs_fs_info *fs_info = inode->root->fs_info;
struct btrfs_root *root = inode->root;
struct extent_state *cached_state = NULL;
u64 lockstart, lockend;
u64 num_bytes;
int ret;
if (!(inode->flags & (BTRFS_INODE_NODATACOW | BTRFS_INODE_PREALLOC)))
return 0;
if (!btrfs_drew_try_write_lock(&root->snapshot_lock))
return -EAGAIN;
lockstart = round_down(pos, fs_info->sectorsize);
lockend = round_up(pos + *write_bytes,
fs_info->sectorsize) - 1;
num_bytes = lockend - lockstart + 1;
if (nowait) {
if (!btrfs_try_lock_ordered_range(inode, lockstart, lockend,
&cached_state)) {
btrfs_drew_write_unlock(&root->snapshot_lock);
return -EAGAIN;
}
} else {
btrfs_lock_and_flush_ordered_range(inode, lockstart, lockend,
&cached_state);
}
ret = can_nocow_extent(&inode->vfs_inode, lockstart, &num_bytes,
NULL, NULL, NULL, nowait, false);
if (ret <= 0)
btrfs_drew_write_unlock(&root->snapshot_lock);
else
*write_bytes = min_t(size_t, *write_bytes ,
num_bytes - pos + lockstart);
unlock_extent(&inode->io_tree, lockstart, lockend, &cached_state);
return ret;
}
void btrfs_check_nocow_unlock(struct btrfs_inode *inode)
{
btrfs_drew_write_unlock(&inode->root->snapshot_lock);
}
static void update_time_for_write(struct inode *inode)
{
struct timespec64 now;
if (IS_NOCMTIME(inode))
return;
now = current_time(inode);
if (!timespec64_equal(&inode->i_mtime, &now))
inode->i_mtime = now;
if (!timespec64_equal(&inode->i_ctime, &now))
inode->i_ctime = now;
if (IS_I_VERSION(inode))
inode_inc_iversion(inode);
}
static int btrfs_write_check(struct kiocb *iocb, struct iov_iter *from,
size_t count)
{
struct file *file = iocb->ki_filp;
struct inode *inode = file_inode(file);
struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
loff_t pos = iocb->ki_pos;
int ret;
loff_t oldsize;
loff_t start_pos;
/*
* Quickly bail out on NOWAIT writes if we don't have the nodatacow or
* prealloc flags, as without those flags we always have to COW. We will
* later check if we can really COW into the target range (using
* can_nocow_extent() at btrfs_get_blocks_direct_write()).
*/
if ((iocb->ki_flags & IOCB_NOWAIT) &&
!(BTRFS_I(inode)->flags & (BTRFS_INODE_NODATACOW | BTRFS_INODE_PREALLOC)))
return -EAGAIN;
current->backing_dev_info = inode_to_bdi(inode);
ret = file_remove_privs(file);
if (ret)
return ret;
/*
* We reserve space for updating the inode when we reserve space for the
* extent we are going to write, so we will enospc out there. We don't
* need to start yet another transaction to update the inode as we will
* update the inode when we finish writing whatever data we write.
*/
update_time_for_write(inode);
start_pos = round_down(pos, fs_info->sectorsize);
oldsize = i_size_read(inode);
if (start_pos > oldsize) {
/* Expand hole size to cover write data, preventing empty gap */
loff_t end_pos = round_up(pos + count, fs_info->sectorsize);
ret = btrfs_cont_expand(BTRFS_I(inode), oldsize, end_pos);
if (ret) {
current->backing_dev_info = NULL;
return ret;
}
}
return 0;
}
static noinline ssize_t btrfs_buffered_write(struct kiocb *iocb,
struct iov_iter *i)
{
struct file *file = iocb->ki_filp;
loff_t pos;
struct inode *inode = file_inode(file);
struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
struct page **pages = NULL;
struct extent_changeset *data_reserved = NULL;
u64 release_bytes = 0;
u64 lockstart;
u64 lockend;
size_t num_written = 0;
int nrptrs;
ssize_t ret;
bool only_release_metadata = false;
bool force_page_uptodate = false;
loff_t old_isize = i_size_read(inode);
unsigned int ilock_flags = 0;
const bool nowait = (iocb->ki_flags & IOCB_NOWAIT);
unsigned int bdp_flags = (nowait ? BDP_ASYNC : 0);
if (nowait)
ilock_flags |= BTRFS_ILOCK_TRY;
ret = btrfs_inode_lock(BTRFS_I(inode), ilock_flags);
if (ret < 0)
return ret;
ret = generic_write_checks(iocb, i);
if (ret <= 0)
goto out;
ret = btrfs_write_check(iocb, i, ret);
if (ret < 0)
goto out;
pos = iocb->ki_pos;
nrptrs = min(DIV_ROUND_UP(iov_iter_count(i), PAGE_SIZE),
PAGE_SIZE / (sizeof(struct page *)));
nrptrs = min(nrptrs, current->nr_dirtied_pause - current->nr_dirtied);
nrptrs = max(nrptrs, 8);
pages = kmalloc_array(nrptrs, sizeof(struct page *), GFP_KERNEL);
if (!pages) {
ret = -ENOMEM;
goto out;
}
while (iov_iter_count(i) > 0) {
struct extent_state *cached_state = NULL;
size_t offset = offset_in_page(pos);
size_t sector_offset;
size_t write_bytes = min(iov_iter_count(i),
nrptrs * (size_t)PAGE_SIZE -
offset);
size_t num_pages;
size_t reserve_bytes;
size_t dirty_pages;
size_t copied;
size_t dirty_sectors;
size_t num_sectors;
int extents_locked;
/*
* Fault pages before locking them in prepare_pages
* to avoid recursive lock
*/
if (unlikely(fault_in_iov_iter_readable(i, write_bytes))) {
ret = -EFAULT;
break;
}
only_release_metadata = false;
sector_offset = pos & (fs_info->sectorsize - 1);
extent_changeset_release(data_reserved);
ret = btrfs_check_data_free_space(BTRFS_I(inode),
&data_reserved, pos,
write_bytes, nowait);
if (ret < 0) {
int can_nocow;
if (nowait && (ret == -ENOSPC || ret == -EAGAIN)) {
ret = -EAGAIN;
break;
}
/*
* If we don't have to COW at the offset, reserve
* metadata only. write_bytes may get smaller than
* requested here.
*/
can_nocow = btrfs_check_nocow_lock(BTRFS_I(inode), pos,
&write_bytes, nowait);
if (can_nocow < 0)
ret = can_nocow;
if (can_nocow > 0)
ret = 0;
if (ret)
break;
only_release_metadata = true;
}
num_pages = DIV_ROUND_UP(write_bytes + offset, PAGE_SIZE);
WARN_ON(num_pages > nrptrs);
reserve_bytes = round_up(write_bytes + sector_offset,
fs_info->sectorsize);
WARN_ON(reserve_bytes == 0);
ret = btrfs_delalloc_reserve_metadata(BTRFS_I(inode),
reserve_bytes,
reserve_bytes, nowait);
if (ret) {
if (!only_release_metadata)
btrfs_free_reserved_data_space(BTRFS_I(inode),
data_reserved, pos,
write_bytes);
else
btrfs_check_nocow_unlock(BTRFS_I(inode));
if (nowait && ret == -ENOSPC)
ret = -EAGAIN;
break;
}
release_bytes = reserve_bytes;
again:
ret = balance_dirty_pages_ratelimited_flags(inode->i_mapping, bdp_flags);
if (ret) {
btrfs_delalloc_release_extents(BTRFS_I(inode), reserve_bytes);
break;
}
/*
* This is going to setup the pages array with the number of
* pages we want, so we don't really need to worry about the
* contents of pages from loop to loop
*/
ret = prepare_pages(inode, pages, num_pages,
pos, write_bytes, force_page_uptodate, false);
if (ret) {
btrfs_delalloc_release_extents(BTRFS_I(inode),
reserve_bytes);
break;
}
extents_locked = lock_and_cleanup_extent_if_need(
BTRFS_I(inode), pages,
num_pages, pos, write_bytes, &lockstart,
&lockend, nowait, &cached_state);
if (extents_locked < 0) {
if (!nowait && extents_locked == -EAGAIN)
goto again;
btrfs_delalloc_release_extents(BTRFS_I(inode),
reserve_bytes);
ret = extents_locked;
break;
}
copied = btrfs_copy_from_user(pos, write_bytes, pages, i);
num_sectors = BTRFS_BYTES_TO_BLKS(fs_info, reserve_bytes);
dirty_sectors = round_up(copied + sector_offset,
fs_info->sectorsize);
dirty_sectors = BTRFS_BYTES_TO_BLKS(fs_info, dirty_sectors);
/*
* if we have trouble faulting in the pages, fall
* back to one page at a time
*/
if (copied < write_bytes)
nrptrs = 1;
if (copied == 0) {
force_page_uptodate = true;
dirty_sectors = 0;
dirty_pages = 0;
} else {
force_page_uptodate = false;
dirty_pages = DIV_ROUND_UP(copied + offset,
PAGE_SIZE);
}
if (num_sectors > dirty_sectors) {
/* release everything except the sectors we dirtied */
release_bytes -= dirty_sectors << fs_info->sectorsize_bits;
if (only_release_metadata) {
btrfs_delalloc_release_metadata(BTRFS_I(inode),
release_bytes, true);
} else {
u64 __pos;
__pos = round_down(pos,
fs_info->sectorsize) +
(dirty_pages << PAGE_SHIFT);
btrfs_delalloc_release_space(BTRFS_I(inode),
data_reserved, __pos,
release_bytes, true);
}
}
release_bytes = round_up(copied + sector_offset,
fs_info->sectorsize);
ret = btrfs_dirty_pages(BTRFS_I(inode), pages,
dirty_pages, pos, copied,
&cached_state, only_release_metadata);
/*
* If we have not locked the extent range, because the range's
* start offset is >= i_size, we might still have a non-NULL
* cached extent state, acquired while marking the extent range
* as delalloc through btrfs_dirty_pages(). Therefore free any
* possible cached extent state to avoid a memory leak.
*/
if (extents_locked)
unlock_extent(&BTRFS_I(inode)->io_tree, lockstart,
lockend, &cached_state);
else
free_extent_state(cached_state);
btrfs_delalloc_release_extents(BTRFS_I(inode), reserve_bytes);
if (ret) {
btrfs_drop_pages(fs_info, pages, num_pages, pos, copied);
break;
}
release_bytes = 0;
if (only_release_metadata)
btrfs_check_nocow_unlock(BTRFS_I(inode));
btrfs_drop_pages(fs_info, pages, num_pages, pos, copied);
cond_resched();
pos += copied;
num_written += copied;
}
kfree(pages);
if (release_bytes) {
if (only_release_metadata) {
btrfs_check_nocow_unlock(BTRFS_I(inode));
btrfs_delalloc_release_metadata(BTRFS_I(inode),
release_bytes, true);
} else {
btrfs_delalloc_release_space(BTRFS_I(inode),
data_reserved,
round_down(pos, fs_info->sectorsize),
release_bytes, true);
}
}
extent_changeset_free(data_reserved);
if (num_written > 0) {
pagecache_isize_extended(inode, old_isize, iocb->ki_pos);
iocb->ki_pos += num_written;
}
out:
btrfs_inode_unlock(BTRFS_I(inode), ilock_flags);
return num_written ? num_written : ret;
}
static ssize_t check_direct_IO(struct btrfs_fs_info *fs_info,
const struct iov_iter *iter, loff_t offset)
{
const u32 blocksize_mask = fs_info->sectorsize - 1;
if (offset & blocksize_mask)
return -EINVAL;
if (iov_iter_alignment(iter) & blocksize_mask)
return -EINVAL;
return 0;
}
static ssize_t btrfs_direct_write(struct kiocb *iocb, struct iov_iter *from)
{
struct file *file = iocb->ki_filp;
struct inode *inode = file_inode(file);
struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
loff_t pos;
ssize_t written = 0;
ssize_t written_buffered;
size_t prev_left = 0;
loff_t endbyte;
ssize_t err;
unsigned int ilock_flags = 0;
struct iomap_dio *dio;
if (iocb->ki_flags & IOCB_NOWAIT)
ilock_flags |= BTRFS_ILOCK_TRY;
/* If the write DIO is within EOF, use a shared lock */
if (iocb->ki_pos + iov_iter_count(from) <= i_size_read(inode))
ilock_flags |= BTRFS_ILOCK_SHARED;
relock:
err = btrfs_inode_lock(BTRFS_I(inode), ilock_flags);
if (err < 0)
return err;
err = generic_write_checks(iocb, from);
if (err <= 0) {
btrfs_inode_unlock(BTRFS_I(inode), ilock_flags);
return err;
}
err = btrfs_write_check(iocb, from, err);
if (err < 0) {
btrfs_inode_unlock(BTRFS_I(inode), ilock_flags);
goto out;
}
pos = iocb->ki_pos;
/*
* Re-check since file size may have changed just before taking the
* lock or pos may have changed because of O_APPEND in generic_write_check()
*/
if ((ilock_flags & BTRFS_ILOCK_SHARED) &&
pos + iov_iter_count(from) > i_size_read(inode)) {
btrfs_inode_unlock(BTRFS_I(inode), ilock_flags);
ilock_flags &= ~BTRFS_ILOCK_SHARED;
goto relock;
}
if (check_direct_IO(fs_info, from, pos)) {
btrfs_inode_unlock(BTRFS_I(inode), ilock_flags);
goto buffered;
}
/*
* The iov_iter can be mapped to the same file range we are writing to.
* If that's the case, then we will deadlock in the iomap code, because
* it first calls our callback btrfs_dio_iomap_begin(), which will create
* an ordered extent, and after that it will fault in the pages that the
* iov_iter refers to. During the fault in we end up in the readahead
* pages code (starting at btrfs_readahead()), which will lock the range,
* find that ordered extent and then wait for it to complete (at
* btrfs_lock_and_flush_ordered_range()), resulting in a deadlock since
* obviously the ordered extent can never complete as we didn't submit
* yet the respective bio(s). This always happens when the buffer is
* memory mapped to the same file range, since the iomap DIO code always
* invalidates pages in the target file range (after starting and waiting
* for any writeback).
*
* So here we disable page faults in the iov_iter and then retry if we
* got -EFAULT, faulting in the pages before the retry.
*/
from->nofault = true;
dio = btrfs_dio_write(iocb, from, written);
from->nofault = false;
/*
* iomap_dio_complete() will call btrfs_sync_file() if we have a dsync
* iocb, and that needs to lock the inode. So unlock it before calling
* iomap_dio_complete() to avoid a deadlock.
*/
btrfs_inode_unlock(BTRFS_I(inode), ilock_flags);
if (IS_ERR_OR_NULL(dio))
err = PTR_ERR_OR_ZERO(dio);
else
err = iomap_dio_complete(dio);
/* No increment (+=) because iomap returns a cumulative value. */
if (err > 0)
written = err;
if (iov_iter_count(from) > 0 && (err == -EFAULT || err > 0)) {
const size_t left = iov_iter_count(from);
/*
* We have more data left to write. Try to fault in as many as
* possible of the remainder pages and retry. We do this without
* releasing and locking again the inode, to prevent races with
* truncate.
*
* Also, in case the iov refers to pages in the file range of the
* file we want to write to (due to a mmap), we could enter an
* infinite loop if we retry after faulting the pages in, since
* iomap will invalidate any pages in the range early on, before
* it tries to fault in the pages of the iov. So we keep track of
* how much was left of iov in the previous EFAULT and fallback
* to buffered IO in case we haven't made any progress.
*/
if (left == prev_left) {
err = -ENOTBLK;
} else {
fault_in_iov_iter_readable(from, left);
prev_left = left;
goto relock;
}
}
/*
* If 'err' is -ENOTBLK or we have not written all data, then it means
* we must fallback to buffered IO.
*/
if ((err < 0 && err != -ENOTBLK) || !iov_iter_count(from))
goto out;
buffered:
/*
* If we are in a NOWAIT context, then return -EAGAIN to signal the caller
* it must retry the operation in a context where blocking is acceptable,
* because even if we end up not blocking during the buffered IO attempt
* below, we will block when flushing and waiting for the IO.
*/
if (iocb->ki_flags & IOCB_NOWAIT) {
err = -EAGAIN;
goto out;
}
pos = iocb->ki_pos;
written_buffered = btrfs_buffered_write(iocb, from);
if (written_buffered < 0) {
err = written_buffered;
goto out;
}
/*
* Ensure all data is persisted. We want the next direct IO read to be
* able to read what was just written.
*/
endbyte = pos + written_buffered - 1;
err = btrfs_fdatawrite_range(inode, pos, endbyte);
if (err)
goto out;
err = filemap_fdatawait_range(inode->i_mapping, pos, endbyte);
if (err)
goto out;
written += written_buffered;
iocb->ki_pos = pos + written_buffered;
invalidate_mapping_pages(file->f_mapping, pos >> PAGE_SHIFT,
endbyte >> PAGE_SHIFT);
out:
return err < 0 ? err : written;
}
static ssize_t btrfs_encoded_write(struct kiocb *iocb, struct iov_iter *from,
const struct btrfs_ioctl_encoded_io_args *encoded)
{
struct file *file = iocb->ki_filp;
struct inode *inode = file_inode(file);
loff_t count;
ssize_t ret;
btrfs_inode_lock(BTRFS_I(inode), 0);
count = encoded->len;
ret = generic_write_checks_count(iocb, &count);
if (ret == 0 && count != encoded->len) {
/*
* The write got truncated by generic_write_checks_count(). We
* can't do a partial encoded write.
*/
ret = -EFBIG;
}
if (ret || encoded->len == 0)
goto out;
ret = btrfs_write_check(iocb, from, encoded->len);
if (ret < 0)
goto out;
ret = btrfs_do_encoded_write(iocb, from, encoded);
out:
btrfs_inode_unlock(BTRFS_I(inode), 0);
return ret;
}
ssize_t btrfs_do_write_iter(struct kiocb *iocb, struct iov_iter *from,
const struct btrfs_ioctl_encoded_io_args *encoded)
{
struct file *file = iocb->ki_filp;
struct btrfs_inode *inode = BTRFS_I(file_inode(file));
ssize_t num_written, num_sync;
const bool sync = iocb_is_dsync(iocb);
/*
* If the fs flips readonly due to some impossible error, although we
* have opened a file as writable, we have to stop this write operation
* to ensure consistency.
*/
if (BTRFS_FS_ERROR(inode->root->fs_info))
return -EROFS;
if (encoded && (iocb->ki_flags & IOCB_NOWAIT))
return -EOPNOTSUPP;
if (sync)
atomic_inc(&inode->sync_writers);
if (encoded) {
num_written = btrfs_encoded_write(iocb, from, encoded);
num_sync = encoded->len;
} else if (iocb->ki_flags & IOCB_DIRECT) {
num_written = btrfs_direct_write(iocb, from);
num_sync = num_written;
} else {
num_written = btrfs_buffered_write(iocb, from);
num_sync = num_written;
}
btrfs_set_inode_last_sub_trans(inode);
if (num_sync > 0) {
num_sync = generic_write_sync(iocb, num_sync);
if (num_sync < 0)
num_written = num_sync;
}
if (sync)
atomic_dec(&inode->sync_writers);
current->backing_dev_info = NULL;
return num_written;
}
static ssize_t btrfs_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
{
return btrfs_do_write_iter(iocb, from, NULL);
}
int btrfs_release_file(struct inode *inode, struct file *filp)
{
struct btrfs_file_private *private = filp->private_data;
if (private) {
kfree(private->filldir_buf);
free_extent_state(private->llseek_cached_state);
kfree(private);
filp->private_data = NULL;
}
/*
* Set by setattr when we are about to truncate a file from a non-zero
* size to a zero size. This tries to flush down new bytes that may
* have been written if the application were using truncate to replace
* a file in place.
*/
if (test_and_clear_bit(BTRFS_INODE_FLUSH_ON_CLOSE,
&BTRFS_I(inode)->runtime_flags))
filemap_flush(inode->i_mapping);
return 0;
}
static int start_ordered_ops(struct inode *inode, loff_t start, loff_t end)
{
int ret;
struct blk_plug plug;
/*
* This is only called in fsync, which would do synchronous writes, so
* a plug can merge adjacent IOs as much as possible. Esp. in case of
* multiple disks using raid profile, a large IO can be split to
* several segments of stripe length (currently 64K).
*/
blk_start_plug(&plug);
atomic_inc(&BTRFS_I(inode)->sync_writers);
ret = btrfs_fdatawrite_range(inode, start, end);
atomic_dec(&BTRFS_I(inode)->sync_writers);
blk_finish_plug(&plug);
return ret;
}
static inline bool skip_inode_logging(const struct btrfs_log_ctx *ctx)
{
struct btrfs_inode *inode = BTRFS_I(ctx->inode);
struct btrfs_fs_info *fs_info = inode->root->fs_info;
if (btrfs_inode_in_log(inode, fs_info->generation) &&
list_empty(&ctx->ordered_extents))
return true;
/*
* If we are doing a fast fsync we can not bail out if the inode's
* last_trans is <= then the last committed transaction, because we only
* update the last_trans of the inode during ordered extent completion,
* and for a fast fsync we don't wait for that, we only wait for the
* writeback to complete.
*/
if (inode->last_trans <= fs_info->last_trans_committed &&
(test_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &inode->runtime_flags) ||
list_empty(&ctx->ordered_extents)))
return true;
return false;
}
/*
* fsync call for both files and directories. This logs the inode into
* the tree log instead of forcing full commits whenever possible.
*
* It needs to call filemap_fdatawait so that all ordered extent updates are
* in the metadata btree are up to date for copying to the log.
*
* It drops the inode mutex before doing the tree log commit. This is an
* important optimization for directories because holding the mutex prevents
* new operations on the dir while we write to disk.
*/
int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
{
struct dentry *dentry = file_dentry(file);
struct inode *inode = d_inode(dentry);
struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
struct btrfs_root *root = BTRFS_I(inode)->root;
struct btrfs_trans_handle *trans;
struct btrfs_log_ctx ctx;
int ret = 0, err;
u64 len;
bool full_sync;
trace_btrfs_sync_file(file, datasync);
btrfs_init_log_ctx(&ctx, inode);
/*
* Always set the range to a full range, otherwise we can get into
* several problems, from missing file extent items to represent holes
* when not using the NO_HOLES feature, to log tree corruption due to
* races between hole detection during logging and completion of ordered
* extents outside the range, to missing checksums due to ordered extents
* for which we flushed only a subset of their pages.
*/
start = 0;
end = LLONG_MAX;
len = (u64)LLONG_MAX + 1;
/*
* We write the dirty pages in the range and wait until they complete
* out of the ->i_mutex. If so, we can flush the dirty pages by
* multi-task, and make the performance up. See
* btrfs_wait_ordered_range for an explanation of the ASYNC check.
*/
ret = start_ordered_ops(inode, start, end);
if (ret)
goto out;
btrfs_inode_lock(BTRFS_I(inode), BTRFS_ILOCK_MMAP);
atomic_inc(&root->log_batch);
/*
* Before we acquired the inode's lock and the mmap lock, someone may
* have dirtied more pages in the target range. We need to make sure
* that writeback for any such pages does not start while we are logging
* the inode, because if it does, any of the following might happen when
* we are not doing a full inode sync:
*
* 1) We log an extent after its writeback finishes but before its
* checksums are added to the csum tree, leading to -EIO errors
* when attempting to read the extent after a log replay.
*
* 2) We can end up logging an extent before its writeback finishes.
* Therefore after the log replay we will have a file extent item
* pointing to an unwritten extent (and no data checksums as well).
*
* So trigger writeback for any eventual new dirty pages and then we
* wait for all ordered extents to complete below.
*/
ret = start_ordered_ops(inode, start, end);
if (ret) {
btrfs_inode_unlock(BTRFS_I(inode), BTRFS_ILOCK_MMAP);
goto out;
}
/*
* Always check for the full sync flag while holding the inode's lock,
* to avoid races with other tasks. The flag must be either set all the
* time during logging or always off all the time while logging.
* We check the flag here after starting delalloc above, because when
* running delalloc the full sync flag may be set if we need to drop
* extra extent map ranges due to temporary memory allocation failures.
*/
full_sync = test_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
&BTRFS_I(inode)->runtime_flags);
/*
* We have to do this here to avoid the priority inversion of waiting on
* IO of a lower priority task while holding a transaction open.
*
* For a full fsync we wait for the ordered extents to complete while
* for a fast fsync we wait just for writeback to complete, and then
* attach the ordered extents to the transaction so that a transaction
* commit waits for their completion, to avoid data loss if we fsync,
* the current transaction commits before the ordered extents complete
* and a power failure happens right after that.
*
* For zoned filesystem, if a write IO uses a ZONE_APPEND command, the
* logical address recorded in the ordered extent may change. We need
* to wait for the IO to stabilize the logical address.
*/
if (full_sync || btrfs_is_zoned(fs_info)) {
ret = btrfs_wait_ordered_range(inode, start, len);
} else {
/*
* Get our ordered extents as soon as possible to avoid doing
* checksum lookups in the csum tree, and use instead the
* checksums attached to the ordered extents.
*/
btrfs_get_ordered_extents_for_logging(BTRFS_I(inode),
&ctx.ordered_extents);
ret = filemap_fdatawait_range(inode->i_mapping, start, end);
}
if (ret)
goto out_release_extents;
atomic_inc(&root->log_batch);
smp_mb();
if (skip_inode_logging(&ctx)) {
/*
* We've had everything committed since the last time we were
* modified so clear this flag in case it was set for whatever
* reason, it's no longer relevant.
*/
clear_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
&BTRFS_I(inode)->runtime_flags);
/*
* An ordered extent might have started before and completed
* already with io errors, in which case the inode was not
* updated and we end up here. So check the inode's mapping
* for any errors that might have happened since we last
* checked called fsync.
*/
ret = filemap_check_wb_err(inode->i_mapping, file->f_wb_err);
goto out_release_extents;
}
/*
* We use start here because we will need to wait on the IO to complete
* in btrfs_sync_log, which could require joining a transaction (for
* example checking cross references in the nocow path). If we use join
* here we could get into a situation where we're waiting on IO to
* happen that is blocked on a transaction trying to commit. With start
* we inc the extwriter counter, so we wait for all extwriters to exit
* before we start blocking joiners. This comment is to keep somebody
* from thinking they are super smart and changing this to
* btrfs_join_transaction *cough*Josef*cough*.
*/
trans = btrfs_start_transaction(root, 0);
if (IS_ERR(trans)) {
ret = PTR_ERR(trans);
goto out_release_extents;
}
trans->in_fsync = true;
ret = btrfs_log_dentry_safe(trans, dentry, &ctx);
btrfs_release_log_ctx_extents(&ctx);
if (ret < 0) {
/* Fallthrough and commit/free transaction. */
ret = BTRFS_LOG_FORCE_COMMIT;
}
/* we've logged all the items and now have a consistent
* version of the file in the log. It is possible that
* someone will come in and modify the file, but that's
* fine because the log is consistent on disk, and we
* have references to all of the file's extents
*
* It is possible that someone will come in and log the
* file again, but that will end up using the synchronization
* inside btrfs_sync_log to keep things safe.
*/
btrfs_inode_unlock(BTRFS_I(inode), BTRFS_ILOCK_MMAP);
if (ret == BTRFS_NO_LOG_SYNC) {
ret = btrfs_end_transaction(trans);
goto out;
}
/* We successfully logged the inode, attempt to sync the log. */
if (!ret) {
ret = btrfs_sync_log(trans, root, &ctx);
if (!ret) {
ret = btrfs_end_transaction(trans);
goto out;
}
}
/*
* At this point we need to commit the transaction because we had
* btrfs_need_log_full_commit() or some other error.
*
* If we didn't do a full sync we have to stop the trans handle, wait on
* the ordered extents, start it again and commit the transaction. If
* we attempt to wait on the ordered extents here we could deadlock with
* something like fallocate() that is holding the extent lock trying to
* start a transaction while some other thread is trying to commit the
* transaction while we (fsync) are currently holding the transaction
* open.
*/
if (!full_sync) {
ret = btrfs_end_transaction(trans);
if (ret)
goto out;
ret = btrfs_wait_ordered_range(inode, start, len);
if (ret)
goto out;
/*
* This is safe to use here because we're only interested in
* making sure the transaction that had the ordered extents is
* committed. We aren't waiting on anything past this point,
* we're purely getting the transaction and committing it.
*/
trans = btrfs_attach_transaction_barrier(root);
if (IS_ERR(trans)) {
ret = PTR_ERR(trans);
/*
* We committed the transaction and there's no currently
* running transaction, this means everything we care
* about made it to disk and we are done.
*/
if (ret == -ENOENT)
ret = 0;
goto out;
}
}
ret = btrfs_commit_transaction(trans);
out:
ASSERT(list_empty(&ctx.list));
ASSERT(list_empty(&ctx.conflict_inodes));
err = file_check_and_advance_wb_err(file);
if (!ret)
ret = err;
return ret > 0 ? -EIO : ret;
out_release_extents:
btrfs_release_log_ctx_extents(&ctx);
btrfs_inode_unlock(BTRFS_I(inode), BTRFS_ILOCK_MMAP);
goto out;
}
static const struct vm_operations_struct btrfs_file_vm_ops = {
.fault = filemap_fault,
.map_pages = filemap_map_pages,
.page_mkwrite = btrfs_page_mkwrite,
};
static int btrfs_file_mmap(struct file *filp, struct vm_area_struct *vma)
{
struct address_space *mapping = filp->f_mapping;
if (!mapping->a_ops->read_folio)
return -ENOEXEC;
file_accessed(filp);
vma->vm_ops = &btrfs_file_vm_ops;
return 0;
}
static int hole_mergeable(struct btrfs_inode *inode, struct extent_buffer *leaf,
int slot, u64 start, u64 end)
{
struct btrfs_file_extent_item *fi;
struct btrfs_key key;
if (slot < 0 || slot >= btrfs_header_nritems(leaf))
return 0;
btrfs_item_key_to_cpu(leaf, &key, slot);
if (key.objectid != btrfs_ino(inode) ||
key.type != BTRFS_EXTENT_DATA_KEY)
return 0;
fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG)
return 0;
if (btrfs_file_extent_disk_bytenr(leaf, fi))
return 0;
if (key.offset == end)
return 1;
if (key.offset + btrfs_file_extent_num_bytes(leaf, fi) == start)
return 1;
return 0;
}
static int fill_holes(struct btrfs_trans_handle *trans,
struct btrfs_inode *inode,
struct btrfs_path *path, u64 offset, u64 end)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_root *root = inode->root;
struct extent_buffer *leaf;
struct btrfs_file_extent_item *fi;
struct extent_map *hole_em;
struct btrfs_key key;
int ret;
if (btrfs_fs_incompat(fs_info, NO_HOLES))
goto out;
key.objectid = btrfs_ino(inode);
key.type = BTRFS_EXTENT_DATA_KEY;
key.offset = offset;
ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
if (ret <= 0) {
/*
* We should have dropped this offset, so if we find it then
* something has gone horribly wrong.
*/
if (ret == 0)
ret = -EINVAL;
return ret;
}
leaf = path->nodes[0];
if (hole_mergeable(inode, leaf, path->slots[0] - 1, offset, end)) {
u64 num_bytes;
path->slots[0]--;
fi = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_file_extent_item);
num_bytes = btrfs_file_extent_num_bytes(leaf, fi) +
end - offset;
btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes);
btrfs_set_file_extent_ram_bytes(leaf, fi, num_bytes);
btrfs_set_file_extent_offset(leaf, fi, 0);
btrfs_set_file_extent_generation(leaf, fi, trans->transid);
btrfs_mark_buffer_dirty(leaf);
goto out;
}
if (hole_mergeable(inode, leaf, path->slots[0], offset, end)) {
u64 num_bytes;
key.offset = offset;
btrfs_set_item_key_safe(fs_info, path, &key);
fi = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_file_extent_item);
num_bytes = btrfs_file_extent_num_bytes(leaf, fi) + end -
offset;
btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes);
btrfs_set_file_extent_ram_bytes(leaf, fi, num_bytes);
btrfs_set_file_extent_offset(leaf, fi, 0);
btrfs_set_file_extent_generation(leaf, fi, trans->transid);
btrfs_mark_buffer_dirty(leaf);
goto out;
}
btrfs_release_path(path);
ret = btrfs_insert_hole_extent(trans, root, btrfs_ino(inode), offset,
end - offset);
if (ret)
return ret;
out:
btrfs_release_path(path);
hole_em = alloc_extent_map();
if (!hole_em) {
btrfs_drop_extent_map_range(inode, offset, end - 1, false);
btrfs_set_inode_full_sync(inode);
} else {
hole_em->start = offset;
hole_em->len = end - offset;
hole_em->ram_bytes = hole_em->len;
hole_em->orig_start = offset;
hole_em->block_start = EXTENT_MAP_HOLE;
hole_em->block_len = 0;
hole_em->orig_block_len = 0;
hole_em->compress_type = BTRFS_COMPRESS_NONE;
hole_em->generation = trans->transid;
ret = btrfs_replace_extent_map_range(inode, hole_em, true);
free_extent_map(hole_em);
if (ret)
btrfs_set_inode_full_sync(inode);
}
return 0;
}
/*
* Find a hole extent on given inode and change start/len to the end of hole
* extent.(hole/vacuum extent whose em->start <= start &&
* em->start + em->len > start)
* When a hole extent is found, return 1 and modify start/len.
*/
static int find_first_non_hole(struct btrfs_inode *inode, u64 *start, u64 *len)
{
struct btrfs_fs_info *fs_info = inode->root->fs_info;
struct extent_map *em;
int ret = 0;
em = btrfs_get_extent(inode, NULL, 0,
round_down(*start, fs_info->sectorsize),
round_up(*len, fs_info->sectorsize));
if (IS_ERR(em))
return PTR_ERR(em);
/* Hole or vacuum extent(only exists in no-hole mode) */
if (em->block_start == EXTENT_MAP_HOLE) {
ret = 1;
*len = em->start + em->len > *start + *len ?
0 : *start + *len - em->start - em->len;
*start = em->start + em->len;
}
free_extent_map(em);
return ret;
}
static void btrfs_punch_hole_lock_range(struct inode *inode,
const u64 lockstart,
const u64 lockend,
struct extent_state **cached_state)
{
/*
* For subpage case, if the range is not at page boundary, we could
* have pages at the leading/tailing part of the range.
* This could lead to dead loop since filemap_range_has_page()
* will always return true.
* So here we need to do extra page alignment for
* filemap_range_has_page().
*/
const u64 page_lockstart = round_up(lockstart, PAGE_SIZE);
const u64 page_lockend = round_down(lockend + 1, PAGE_SIZE) - 1;
while (1) {
truncate_pagecache_range(inode, lockstart, lockend);
lock_extent(&BTRFS_I(inode)->io_tree, lockstart, lockend,
cached_state);
/*
* We can't have ordered extents in the range, nor dirty/writeback
* pages, because we have locked the inode's VFS lock in exclusive
* mode, we have locked the inode's i_mmap_lock in exclusive mode,
* we have flushed all delalloc in the range and we have waited
* for any ordered extents in the range to complete.
* We can race with anyone reading pages from this range, so after
* locking the range check if we have pages in the range, and if
* we do, unlock the range and retry.
*/
if (!filemap_range_has_page(inode->i_mapping, page_lockstart,
page_lockend))
break;
unlock_extent(&BTRFS_I(inode)->io_tree, lockstart, lockend,
cached_state);
}
btrfs_assert_inode_range_clean(BTRFS_I(inode), lockstart, lockend);
}
static int btrfs_insert_replace_extent(struct btrfs_trans_handle *trans,
struct btrfs_inode *inode,
struct btrfs_path *path,
struct btrfs_replace_extent_info *extent_info,
const u64 replace_len,
const u64 bytes_to_drop)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_root *root = inode->root;
struct btrfs_file_extent_item *extent;
struct extent_buffer *leaf;
struct btrfs_key key;
int slot;
struct btrfs_ref ref = { 0 };
int ret;
if (replace_len == 0)
return 0;
if (extent_info->disk_offset == 0 &&
btrfs_fs_incompat(fs_info, NO_HOLES)) {
btrfs_update_inode_bytes(inode, 0, bytes_to_drop);
return 0;
}
key.objectid = btrfs_ino(inode);
key.type = BTRFS_EXTENT_DATA_KEY;
key.offset = extent_info->file_offset;
ret = btrfs_insert_empty_item(trans, root, path, &key,
sizeof(struct btrfs_file_extent_item));
if (ret)
return ret;
leaf = path->nodes[0];
slot = path->slots[0];
write_extent_buffer(leaf, extent_info->extent_buf,
btrfs_item_ptr_offset(leaf, slot),
sizeof(struct btrfs_file_extent_item));
extent = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
ASSERT(btrfs_file_extent_type(leaf, extent) != BTRFS_FILE_EXTENT_INLINE);
btrfs_set_file_extent_offset(leaf, extent, extent_info->data_offset);
btrfs_set_file_extent_num_bytes(leaf, extent, replace_len);
if (extent_info->is_new_extent)
btrfs_set_file_extent_generation(leaf, extent, trans->transid);
btrfs_mark_buffer_dirty(leaf);
btrfs_release_path(path);
ret = btrfs_inode_set_file_extent_range(inode, extent_info->file_offset,
replace_len);
if (ret)
return ret;
/* If it's a hole, nothing more needs to be done. */
if (extent_info->disk_offset == 0) {
btrfs_update_inode_bytes(inode, 0, bytes_to_drop);
return 0;
}
btrfs_update_inode_bytes(inode, replace_len, bytes_to_drop);
if (extent_info->is_new_extent && extent_info->insertions == 0) {
key.objectid = extent_info->disk_offset;
key.type = BTRFS_EXTENT_ITEM_KEY;
key.offset = extent_info->disk_len;
ret = btrfs_alloc_reserved_file_extent(trans, root,
btrfs_ino(inode),
extent_info->file_offset,
extent_info->qgroup_reserved,
&key);
} else {
u64 ref_offset;
btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF,
extent_info->disk_offset,
extent_info->disk_len, 0);
ref_offset = extent_info->file_offset - extent_info->data_offset;
btrfs_init_data_ref(&ref, root->root_key.objectid,
btrfs_ino(inode), ref_offset, 0, false);
ret = btrfs_inc_extent_ref(trans, &ref);
}
extent_info->insertions++;
return ret;
}
/*
* The respective range must have been previously locked, as well as the inode.
* The end offset is inclusive (last byte of the range).
* @extent_info is NULL for fallocate's hole punching and non-NULL when replacing
* the file range with an extent.
* When not punching a hole, we don't want to end up in a state where we dropped
* extents without inserting a new one, so we must abort the transaction to avoid
* a corruption.
*/
int btrfs_replace_file_extents(struct btrfs_inode *inode,
struct btrfs_path *path, const u64 start,
const u64 end,
struct btrfs_replace_extent_info *extent_info,
struct btrfs_trans_handle **trans_out)
{
struct btrfs_drop_extents_args drop_args = { 0 };
struct btrfs_root *root = inode->root;
struct btrfs_fs_info *fs_info = root->fs_info;
u64 min_size = btrfs_calc_insert_metadata_size(fs_info, 1);
u64 ino_size = round_up(inode->vfs_inode.i_size, fs_info->sectorsize);
struct btrfs_trans_handle *trans = NULL;
struct btrfs_block_rsv *rsv;
unsigned int rsv_count;
u64 cur_offset;
u64 len = end - start;
int ret = 0;
if (end <= start)
return -EINVAL;
rsv = btrfs_alloc_block_rsv(fs_info, BTRFS_BLOCK_RSV_TEMP);
if (!rsv) {
ret = -ENOMEM;
goto out;
}
rsv->size = btrfs_calc_insert_metadata_size(fs_info, 1);
rsv->failfast = true;
/*
* 1 - update the inode
* 1 - removing the extents in the range
* 1 - adding the hole extent if no_holes isn't set or if we are
* replacing the range with a new extent
*/
if (!btrfs_fs_incompat(fs_info, NO_HOLES) || extent_info)
rsv_count = 3;
else
rsv_count = 2;
trans = btrfs_start_transaction(root, rsv_count);
if (IS_ERR(trans)) {
ret = PTR_ERR(trans);
trans = NULL;
goto out_free;
}
ret = btrfs_block_rsv_migrate(&fs_info->trans_block_rsv, rsv,
min_size, false);
if (WARN_ON(ret))
goto out_trans;
trans->block_rsv = rsv;
cur_offset = start;
drop_args.path = path;
drop_args.end = end + 1;
drop_args.drop_cache = true;
while (cur_offset < end) {
drop_args.start = cur_offset;
ret = btrfs_drop_extents(trans, root, inode, &drop_args);
/* If we are punching a hole decrement the inode's byte count */
if (!extent_info)
btrfs_update_inode_bytes(inode, 0,
drop_args.bytes_found);
if (ret != -ENOSPC) {
/*
* The only time we don't want to abort is if we are
* attempting to clone a partial inline extent, in which
* case we'll get EOPNOTSUPP. However if we aren't
* clone we need to abort no matter what, because if we
* got EOPNOTSUPP via prealloc then we messed up and
* need to abort.
*/
if (ret &&
(ret != -EOPNOTSUPP ||
(extent_info && extent_info->is_new_extent)))
btrfs_abort_transaction(trans, ret);
break;
}
trans->block_rsv = &fs_info->trans_block_rsv;
if (!extent_info && cur_offset < drop_args.drop_end &&
cur_offset < ino_size) {
ret = fill_holes(trans, inode, path, cur_offset,
drop_args.drop_end);
if (ret) {
/*
* If we failed then we didn't insert our hole
* entries for the area we dropped, so now the
* fs is corrupted, so we must abort the
* transaction.
*/
btrfs_abort_transaction(trans, ret);
break;
}
} else if (!extent_info && cur_offset < drop_args.drop_end) {
/*
* We are past the i_size here, but since we didn't
* insert holes we need to clear the mapped area so we
* know to not set disk_i_size in this area until a new
* file extent is inserted here.
*/
ret = btrfs_inode_clear_file_extent_range(inode,
cur_offset,
drop_args.drop_end - cur_offset);
if (ret) {
/*
* We couldn't clear our area, so we could
* presumably adjust up and corrupt the fs, so
* we need to abort.
*/
btrfs_abort_transaction(trans, ret);
break;
}
}
if (extent_info &&
drop_args.drop_end > extent_info->file_offset) {
u64 replace_len = drop_args.drop_end -
extent_info->file_offset;
ret = btrfs_insert_replace_extent(trans, inode, path,
extent_info, replace_len,
drop_args.bytes_found);
if (ret) {
btrfs_abort_transaction(trans, ret);
break;
}
extent_info->data_len -= replace_len;
extent_info->data_offset += replace_len;
extent_info->file_offset += replace_len;
}
/*
* We are releasing our handle on the transaction, balance the
* dirty pages of the btree inode and flush delayed items, and
* then get a new transaction handle, which may now point to a
* new transaction in case someone else may have committed the
* transaction we used to replace/drop file extent items. So
* bump the inode's iversion and update mtime and ctime except
* if we are called from a dedupe context. This is because a
* power failure/crash may happen after the transaction is
* committed and before we finish replacing/dropping all the
* file extent items we need.
*/
inode_inc_iversion(&inode->vfs_inode);
if (!extent_info || extent_info->update_times) {
inode->vfs_inode.i_mtime = current_time(&inode->vfs_inode);
inode->vfs_inode.i_ctime = inode->vfs_inode.i_mtime;
}
ret = btrfs_update_inode(trans, root, inode);
if (ret)
break;
btrfs_end_transaction(trans);
btrfs_btree_balance_dirty(fs_info);
trans = btrfs_start_transaction(root, rsv_count);
if (IS_ERR(trans)) {
ret = PTR_ERR(trans);
trans = NULL;
break;
}
ret = btrfs_block_rsv_migrate(&fs_info->trans_block_rsv,
rsv, min_size, false);
if (WARN_ON(ret))
break;
trans->block_rsv = rsv;
cur_offset = drop_args.drop_end;
len = end - cur_offset;
if (!extent_info && len) {
ret = find_first_non_hole(inode, &cur_offset, &len);
if (unlikely(ret < 0))
break;
if (ret && !len) {
ret = 0;
break;
}
}
}
/*
* If we were cloning, force the next fsync to be a full one since we
* we replaced (or just dropped in the case of cloning holes when
* NO_HOLES is enabled) file extent items and did not setup new extent
* maps for the replacement extents (or holes).
*/
if (extent_info && !extent_info->is_new_extent)
btrfs_set_inode_full_sync(inode);
if (ret)
goto out_trans;
trans->block_rsv = &fs_info->trans_block_rsv;
/*
* If we are using the NO_HOLES feature we might have had already an
* hole that overlaps a part of the region [lockstart, lockend] and
* ends at (or beyond) lockend. Since we have no file extent items to
* represent holes, drop_end can be less than lockend and so we must
* make sure we have an extent map representing the existing hole (the
* call to __btrfs_drop_extents() might have dropped the existing extent
* map representing the existing hole), otherwise the fast fsync path
* will not record the existence of the hole region
* [existing_hole_start, lockend].
*/
if (drop_args.drop_end <= end)
drop_args.drop_end = end + 1;
/*
* Don't insert file hole extent item if it's for a range beyond eof
* (because it's useless) or if it represents a 0 bytes range (when
* cur_offset == drop_end).
*/
if (!extent_info && cur_offset < ino_size &&
cur_offset < drop_args.drop_end) {
ret = fill_holes(trans, inode, path, cur_offset,
drop_args.drop_end);
if (ret) {
/* Same comment as above. */
btrfs_abort_transaction(trans, ret);
goto out_trans;
}
} else if (!extent_info && cur_offset < drop_args.drop_end) {
/* See the comment in the loop above for the reasoning here. */
ret = btrfs_inode_clear_file_extent_range(inode, cur_offset,
drop_args.drop_end - cur_offset);
if (ret) {
btrfs_abort_transaction(trans, ret);
goto out_trans;
}
}
if (extent_info) {
ret = btrfs_insert_replace_extent(trans, inode, path,
extent_info, extent_info->data_len,
drop_args.bytes_found);
if (ret) {
btrfs_abort_transaction(trans, ret);
goto out_trans;
}
}
out_trans:
if (!trans)
goto out_free;
trans->block_rsv = &fs_info->trans_block_rsv;
if (ret)
btrfs_end_transaction(trans);
else
*trans_out = trans;
out_free:
btrfs_free_block_rsv(fs_info, rsv);
out:
return ret;
}
static int btrfs_punch_hole(struct file *file, loff_t offset, loff_t len)
{
struct inode *inode = file_inode(file);
struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
struct btrfs_root *root = BTRFS_I(inode)->root;
struct extent_state *cached_state = NULL;
struct btrfs_path *path;
struct btrfs_trans_handle *trans = NULL;
u64 lockstart;
u64 lockend;
u64 tail_start;
u64 tail_len;
u64 orig_start = offset;
int ret = 0;
bool same_block;
u64 ino_size;
bool truncated_block = false;
bool updated_inode = false;
btrfs_inode_lock(BTRFS_I(inode), BTRFS_ILOCK_MMAP);
ret = btrfs_wait_ordered_range(inode, offset, len);
if (ret)
goto out_only_mutex;
ino_size = round_up(inode->i_size, fs_info->sectorsize);
ret = find_first_non_hole(BTRFS_I(inode), &offset, &len);
if (ret < 0)
goto out_only_mutex;
if (ret && !len) {
/* Already in a large hole */
ret = 0;
goto out_only_mutex;
}
ret = file_modified(file);
if (ret)
goto out_only_mutex;
lockstart = round_up(offset, fs_info->sectorsize);
lockend = round_down(offset + len, fs_info->sectorsize) - 1;
same_block = (BTRFS_BYTES_TO_BLKS(fs_info, offset))
== (BTRFS_BYTES_TO_BLKS(fs_info, offset + len - 1));
/*
* We needn't truncate any block which is beyond the end of the file
* because we are sure there is no data there.
*/
/*
* Only do this if we are in the same block and we aren't doing the
* entire block.
*/
if (same_block && len < fs_info->sectorsize) {
if (offset < ino_size) {
truncated_block = true;
ret = btrfs_truncate_block(BTRFS_I(inode), offset, len,
0);
} else {
ret = 0;
}
goto out_only_mutex;
}
/* zero back part of the first block */
if (offset < ino_size) {
truncated_block = true;
ret = btrfs_truncate_block(BTRFS_I(inode), offset, 0, 0);
if (ret) {
btrfs_inode_unlock(BTRFS_I(inode), BTRFS_ILOCK_MMAP);
return ret;
}
}
/* Check the aligned pages after the first unaligned page,
* if offset != orig_start, which means the first unaligned page
* including several following pages are already in holes,
* the extra check can be skipped */
if (offset == orig_start) {
/* after truncate page, check hole again */
len = offset + len - lockstart;
offset = lockstart;
ret = find_first_non_hole(BTRFS_I(inode), &offset, &len);
if (ret < 0)
goto out_only_mutex;
if (ret && !len) {
ret = 0;
goto out_only_mutex;
}
lockstart = offset;
}
/* Check the tail unaligned part is in a hole */
tail_start = lockend + 1;
tail_len = offset + len - tail_start;
if (tail_len) {
ret = find_first_non_hole(BTRFS_I(inode), &tail_start, &tail_len);
if (unlikely(ret < 0))
goto out_only_mutex;
if (!ret) {
/* zero the front end of the last page */
if (tail_start + tail_len < ino_size) {
truncated_block = true;
ret = btrfs_truncate_block(BTRFS_I(inode),
tail_start + tail_len,
0, 1);
if (ret)
goto out_only_mutex;
}
}
}
if (lockend < lockstart) {
ret = 0;
goto out_only_mutex;
}
btrfs_punch_hole_lock_range(inode, lockstart, lockend, &cached_state);
path = btrfs_alloc_path();
if (!path) {
ret = -ENOMEM;
goto out;
}
ret = btrfs_replace_file_extents(BTRFS_I(inode), path, lockstart,
lockend, NULL, &trans);
btrfs_free_path(path);
if (ret)
goto out;
ASSERT(trans != NULL);
inode_inc_iversion(inode);
inode->i_mtime = current_time(inode);
inode->i_ctime = inode->i_mtime;
ret = btrfs_update_inode(trans, root, BTRFS_I(inode));
updated_inode = true;
btrfs_end_transaction(trans);
btrfs_btree_balance_dirty(fs_info);
out:
unlock_extent(&BTRFS_I(inode)->io_tree, lockstart, lockend,
&cached_state);
out_only_mutex:
if (!updated_inode && truncated_block && !ret) {
/*
* If we only end up zeroing part of a page, we still need to
* update the inode item, so that all the time fields are
* updated as well as the necessary btrfs inode in memory fields
* for detecting, at fsync time, if the inode isn't yet in the
* log tree or it's there but not up to date.
*/
struct timespec64 now = current_time(inode);
inode_inc_iversion(inode);
inode->i_mtime = now;
inode->i_ctime = now;
trans = btrfs_start_transaction(root, 1);
if (IS_ERR(trans)) {
ret = PTR_ERR(trans);
} else {
int ret2;
ret = btrfs_update_inode(trans, root, BTRFS_I(inode));
ret2 = btrfs_end_transaction(trans);
if (!ret)
ret = ret2;
}
}
btrfs_inode_unlock(BTRFS_I(inode), BTRFS_ILOCK_MMAP);
return ret;
}
/* Helper structure to record which range is already reserved */
struct falloc_range {
struct list_head list;
u64 start;
u64 len;
};
/*
* Helper function to add falloc range
*
* Caller should have locked the larger range of extent containing
* [start, len)
*/
static int add_falloc_range(struct list_head *head, u64 start, u64 len)
{
struct falloc_range *range = NULL;
if (!list_empty(head)) {
/*
* As fallocate iterates by bytenr order, we only need to check
* the last range.
*/
range = list_last_entry(head, struct falloc_range, list);
if (range->start + range->len == start) {
range->len += len;
return 0;
}
}
range = kmalloc(sizeof(*range), GFP_KERNEL);
if (!range)
return -ENOMEM;
range->start = start;
range->len = len;
list_add_tail(&range->list, head);
return 0;
}
static int btrfs_fallocate_update_isize(struct inode *inode,
const u64 end,
const int mode)
{
struct btrfs_trans_handle *trans;
struct btrfs_root *root = BTRFS_I(inode)->root;
int ret;
int ret2;
if (mode & FALLOC_FL_KEEP_SIZE || end <= i_size_read(inode))
return 0;
trans = btrfs_start_transaction(root, 1);
if (IS_ERR(trans))
return PTR_ERR(trans);
inode->i_ctime = current_time(inode);
i_size_write(inode, end);
btrfs_inode_safe_disk_i_size_write(BTRFS_I(inode), 0);
ret = btrfs_update_inode(trans, root, BTRFS_I(inode));
ret2 = btrfs_end_transaction(trans);
return ret ? ret : ret2;
}
enum {
RANGE_BOUNDARY_WRITTEN_EXTENT,
RANGE_BOUNDARY_PREALLOC_EXTENT,
RANGE_BOUNDARY_HOLE,
};
static int btrfs_zero_range_check_range_boundary(struct btrfs_inode *inode,
u64 offset)
{
const u64 sectorsize = inode->root->fs_info->sectorsize;
struct extent_map *em;
int ret;
offset = round_down(offset, sectorsize);
em = btrfs_get_extent(inode, NULL, 0, offset, sectorsize);
if (IS_ERR(em))
return PTR_ERR(em);
if (em->block_start == EXTENT_MAP_HOLE)
ret = RANGE_BOUNDARY_HOLE;
else if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
ret = RANGE_BOUNDARY_PREALLOC_EXTENT;
else
ret = RANGE_BOUNDARY_WRITTEN_EXTENT;
free_extent_map(em);
return ret;
}
static int btrfs_zero_range(struct inode *inode,
loff_t offset,
loff_t len,
const int mode)
{
struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
struct extent_map *em;
struct extent_changeset *data_reserved = NULL;
int ret;
u64 alloc_hint = 0;
const u64 sectorsize = fs_info->sectorsize;
u64 alloc_start = round_down(offset, sectorsize);
u64 alloc_end = round_up(offset + len, sectorsize);
u64 bytes_to_reserve = 0;
bool space_reserved = false;
em = btrfs_get_extent(BTRFS_I(inode), NULL, 0, alloc_start,
alloc_end - alloc_start);
if (IS_ERR(em)) {
ret = PTR_ERR(em);
goto out;
}
/*
* Avoid hole punching and extent allocation for some cases. More cases
* could be considered, but these are unlikely common and we keep things
* as simple as possible for now. Also, intentionally, if the target
* range contains one or more prealloc extents together with regular
* extents and holes, we drop all the existing extents and allocate a
* new prealloc extent, so that we get a larger contiguous disk extent.
*/
if (em->start <= alloc_start &&
test_bit(EXTENT_FLAG_PREALLOC, &em->flags)) {
const u64 em_end = em->start + em->len;
if (em_end >= offset + len) {
/*
* The whole range is already a prealloc extent,
* do nothing except updating the inode's i_size if
* needed.
*/
free_extent_map(em);
ret = btrfs_fallocate_update_isize(inode, offset + len,
mode);
goto out;
}
/*
* Part of the range is already a prealloc extent, so operate
* only on the remaining part of the range.
*/
alloc_start = em_end;
ASSERT(IS_ALIGNED(alloc_start, sectorsize));
len = offset + len - alloc_start;
offset = alloc_start;
alloc_hint = em->block_start + em->len;
}
free_extent_map(em);
if (BTRFS_BYTES_TO_BLKS(fs_info, offset) ==
BTRFS_BYTES_TO_BLKS(fs_info, offset + len - 1)) {
em = btrfs_get_extent(BTRFS_I(inode), NULL, 0, alloc_start,
sectorsize);
if (IS_ERR(em)) {
ret = PTR_ERR(em);
goto out;
}
if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags)) {
free_extent_map(em);
ret = btrfs_fallocate_update_isize(inode, offset + len,
mode);
goto out;
}
if (len < sectorsize && em->block_start != EXTENT_MAP_HOLE) {
free_extent_map(em);
ret = btrfs_truncate_block(BTRFS_I(inode), offset, len,
0);
if (!ret)
ret = btrfs_fallocate_update_isize(inode,
offset + len,
mode);
return ret;
}
free_extent_map(em);
alloc_start = round_down(offset, sectorsize);
alloc_end = alloc_start + sectorsize;
goto reserve_space;
}
alloc_start = round_up(offset, sectorsize);
alloc_end = round_down(offset + len, sectorsize);
/*
* For unaligned ranges, check the pages at the boundaries, they might
* map to an extent, in which case we need to partially zero them, or
* they might map to a hole, in which case we need our allocation range
* to cover them.
*/
if (!IS_ALIGNED(offset, sectorsize)) {
ret = btrfs_zero_range_check_range_boundary(BTRFS_I(inode),
offset);
if (ret < 0)
goto out;
if (ret == RANGE_BOUNDARY_HOLE) {
alloc_start = round_down(offset, sectorsize);
ret = 0;
} else if (ret == RANGE_BOUNDARY_WRITTEN_EXTENT) {
ret = btrfs_truncate_block(BTRFS_I(inode), offset, 0, 0);
if (ret)
goto out;
} else {
ret = 0;
}
}
if (!IS_ALIGNED(offset + len, sectorsize)) {
ret = btrfs_zero_range_check_range_boundary(BTRFS_I(inode),
offset + len);
if (ret < 0)
goto out;
if (ret == RANGE_BOUNDARY_HOLE) {
alloc_end = round_up(offset + len, sectorsize);
ret = 0;
} else if (ret == RANGE_BOUNDARY_WRITTEN_EXTENT) {
ret = btrfs_truncate_block(BTRFS_I(inode), offset + len,
0, 1);
if (ret)
goto out;
} else {
ret = 0;
}
}
reserve_space:
if (alloc_start < alloc_end) {
struct extent_state *cached_state = NULL;
const u64 lockstart = alloc_start;
const u64 lockend = alloc_end - 1;
bytes_to_reserve = alloc_end - alloc_start;
ret = btrfs_alloc_data_chunk_ondemand(BTRFS_I(inode),
bytes_to_reserve);
if (ret < 0)
goto out;
space_reserved = true;
btrfs_punch_hole_lock_range(inode, lockstart, lockend,
&cached_state);
ret = btrfs_qgroup_reserve_data(BTRFS_I(inode), &data_reserved,
alloc_start, bytes_to_reserve);
if (ret) {
unlock_extent(&BTRFS_I(inode)->io_tree, lockstart,
lockend, &cached_state);
goto out;
}
ret = btrfs_prealloc_file_range(inode, mode, alloc_start,
alloc_end - alloc_start,
i_blocksize(inode),
offset + len, &alloc_hint);
unlock_extent(&BTRFS_I(inode)->io_tree, lockstart, lockend,
&cached_state);
/* btrfs_prealloc_file_range releases reserved space on error */
if (ret) {
space_reserved = false;
goto out;
}
}
ret = btrfs_fallocate_update_isize(inode, offset + len, mode);
out:
if (ret && space_reserved)
btrfs_free_reserved_data_space(BTRFS_I(inode), data_reserved,
alloc_start, bytes_to_reserve);
extent_changeset_free(data_reserved);
return ret;
}
static long btrfs_fallocate(struct file *file, int mode,
loff_t offset, loff_t len)
{
struct inode *inode = file_inode(file);
struct extent_state *cached_state = NULL;
struct extent_changeset *data_reserved = NULL;
struct falloc_range *range;
struct falloc_range *tmp;
struct list_head reserve_list;
u64 cur_offset;
u64 last_byte;
u64 alloc_start;
u64 alloc_end;
u64 alloc_hint = 0;
u64 locked_end;
u64 actual_end = 0;
u64 data_space_needed = 0;
u64 data_space_reserved = 0;
u64 qgroup_reserved = 0;
struct extent_map *em;
int blocksize = BTRFS_I(inode)->root->fs_info->sectorsize;
int ret;
/* Do not allow fallocate in ZONED mode */
if (btrfs_is_zoned(btrfs_sb(inode->i_sb)))
return -EOPNOTSUPP;
alloc_start = round_down(offset, blocksize);
alloc_end = round_up(offset + len, blocksize);
cur_offset = alloc_start;
/* Make sure we aren't being give some crap mode */
if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE |
FALLOC_FL_ZERO_RANGE))
return -EOPNOTSUPP;
if (mode & FALLOC_FL_PUNCH_HOLE)
return btrfs_punch_hole(file, offset, len);
btrfs_inode_lock(BTRFS_I(inode), BTRFS_ILOCK_MMAP);
if (!(mode & FALLOC_FL_KEEP_SIZE) && offset + len > inode->i_size) {
ret = inode_newsize_ok(inode, offset + len);
if (ret)
goto out;
}
ret = file_modified(file);
if (ret)
goto out;
/*
* TODO: Move these two operations after we have checked
* accurate reserved space, or fallocate can still fail but
* with page truncated or size expanded.
*
* But that's a minor problem and won't do much harm BTW.
*/
if (alloc_start > inode->i_size) {
ret = btrfs_cont_expand(BTRFS_I(inode), i_size_read(inode),
alloc_start);
if (ret)
goto out;
} else if (offset + len > inode->i_size) {
/*
* If we are fallocating from the end of the file onward we
* need to zero out the end of the block if i_size lands in the
* middle of a block.
*/
ret = btrfs_truncate_block(BTRFS_I(inode), inode->i_size, 0, 0);
if (ret)
goto out;
}
/*
* We have locked the inode at the VFS level (in exclusive mode) and we
* have locked the i_mmap_lock lock (in exclusive mode). Now before
* locking the file range, flush all dealloc in the range and wait for
* all ordered extents in the range to complete. After this we can lock
* the file range and, due to the previous locking we did, we know there
* can't be more delalloc or ordered extents in the range.
*/
ret = btrfs_wait_ordered_range(inode, alloc_start,
alloc_end - alloc_start);
if (ret)
goto out;
if (mode & FALLOC_FL_ZERO_RANGE) {
ret = btrfs_zero_range(inode, offset, len, mode);
btrfs_inode_unlock(BTRFS_I(inode), BTRFS_ILOCK_MMAP);
return ret;
}
locked_end = alloc_end - 1;
lock_extent(&BTRFS_I(inode)->io_tree, alloc_start, locked_end,
&cached_state);
btrfs_assert_inode_range_clean(BTRFS_I(inode), alloc_start, locked_end);
/* First, check if we exceed the qgroup limit */
INIT_LIST_HEAD(&reserve_list);
while (cur_offset < alloc_end) {
em = btrfs_get_extent(BTRFS_I(inode), NULL, 0, cur_offset,
alloc_end - cur_offset);
if (IS_ERR(em)) {
ret = PTR_ERR(em);
break;
}
last_byte = min(extent_map_end(em), alloc_end);
actual_end = min_t(u64, extent_map_end(em), offset + len);
last_byte = ALIGN(last_byte, blocksize);
if (em->block_start == EXTENT_MAP_HOLE ||
(cur_offset >= inode->i_size &&
!test_bit(EXTENT_FLAG_PREALLOC, &em->flags))) {
const u64 range_len = last_byte - cur_offset;
ret = add_falloc_range(&reserve_list, cur_offset, range_len);
if (ret < 0) {
free_extent_map(em);
break;
}
ret = btrfs_qgroup_reserve_data(BTRFS_I(inode),
&data_reserved, cur_offset, range_len);
if (ret < 0) {
free_extent_map(em);
break;
}
qgroup_reserved += range_len;
data_space_needed += range_len;
}
free_extent_map(em);
cur_offset = last_byte;
}
if (!ret && data_space_needed > 0) {
/*
* We are safe to reserve space here as we can't have delalloc
* in the range, see above.
*/
ret = btrfs_alloc_data_chunk_ondemand(BTRFS_I(inode),
data_space_needed);
if (!ret)
data_space_reserved = data_space_needed;
}
/*
* If ret is still 0, means we're OK to fallocate.
* Or just cleanup the list and exit.
*/
list_for_each_entry_safe(range, tmp, &reserve_list, list) {
if (!ret) {
ret = btrfs_prealloc_file_range(inode, mode,
range->start,
range->len, i_blocksize(inode),
offset + len, &alloc_hint);
/*
* btrfs_prealloc_file_range() releases space even
* if it returns an error.
*/
data_space_reserved -= range->len;
qgroup_reserved -= range->len;
} else if (data_space_reserved > 0) {
btrfs_free_reserved_data_space(BTRFS_I(inode),
data_reserved, range->start,
range->len);
data_space_reserved -= range->len;
qgroup_reserved -= range->len;
} else if (qgroup_reserved > 0) {
btrfs_qgroup_free_data(BTRFS_I(inode), data_reserved,
range->start, range->len);
qgroup_reserved -= range->len;
}
list_del(&range->list);
kfree(range);
}
if (ret < 0)
goto out_unlock;
/*
* We didn't need to allocate any more space, but we still extended the
* size of the file so we need to update i_size and the inode item.
*/
ret = btrfs_fallocate_update_isize(inode, actual_end, mode);
out_unlock:
unlock_extent(&BTRFS_I(inode)->io_tree, alloc_start, locked_end,
&cached_state);
out:
btrfs_inode_unlock(BTRFS_I(inode), BTRFS_ILOCK_MMAP);
extent_changeset_free(data_reserved);
return ret;
}
/*
* Helper for btrfs_find_delalloc_in_range(). Find a subrange in a given range
* that has unflushed and/or flushing delalloc. There might be other adjacent
* subranges after the one it found, so btrfs_find_delalloc_in_range() keeps
* looping while it gets adjacent subranges, and merging them together.
*/
static bool find_delalloc_subrange(struct btrfs_inode *inode, u64 start, u64 end,
struct extent_state **cached_state,
bool *search_io_tree,
u64 *delalloc_start_ret, u64 *delalloc_end_ret)
{
u64 len = end + 1 - start;
u64 delalloc_len = 0;
struct btrfs_ordered_extent *oe;
u64 oe_start;
u64 oe_end;
/*
* Search the io tree first for EXTENT_DELALLOC. If we find any, it
* means we have delalloc (dirty pages) for which writeback has not
* started yet.
*/
if (*search_io_tree) {
spin_lock(&inode->lock);
if (inode->delalloc_bytes > 0) {
spin_unlock(&inode->lock);
*delalloc_start_ret = start;
delalloc_len = count_range_bits(&inode->io_tree,
delalloc_start_ret, end,
len, EXTENT_DELALLOC, 1,
cached_state);
} else {
spin_unlock(&inode->lock);
}
}
if (delalloc_len > 0) {
/*
* If delalloc was found then *delalloc_start_ret has a sector size
* aligned value (rounded down).
*/
*delalloc_end_ret = *delalloc_start_ret + delalloc_len - 1;
if (*delalloc_start_ret == start) {
/* Delalloc for the whole range, nothing more to do. */
if (*delalloc_end_ret == end)
return true;
/* Else trim our search range for ordered extents. */
start = *delalloc_end_ret + 1;
len = end + 1 - start;
}
} else {
/* No delalloc, future calls don't need to search again. */
*search_io_tree = false;
}
/*
* Now also check if there's any ordered extent in the range.
* We do this because:
*
* 1) When delalloc is flushed, the file range is locked, we clear the
* EXTENT_DELALLOC bit from the io tree and create an extent map and
* an ordered extent for the write. So we might just have been called
* after delalloc is flushed and before the ordered extent completes
* and inserts the new file extent item in the subvolume's btree;
*
* 2) We may have an ordered extent created by flushing delalloc for a
* subrange that starts before the subrange we found marked with
* EXTENT_DELALLOC in the io tree.
*
* We could also use the extent map tree to find such delalloc that is
* being flushed, but using the ordered extents tree is more efficient
* because it's usually much smaller as ordered extents are removed from
* the tree once they complete. With the extent maps, we mau have them
* in the extent map tree for a very long time, and they were either
* created by previous writes or loaded by read operations.
*/
oe = btrfs_lookup_first_ordered_range(inode, start, len);
if (!oe)
return (delalloc_len > 0);
/* The ordered extent may span beyond our search range. */
oe_start = max(oe->file_offset, start);
oe_end = min(oe->file_offset + oe->num_bytes - 1, end);
btrfs_put_ordered_extent(oe);
/* Don't have unflushed delalloc, return the ordered extent range. */
if (delalloc_len == 0) {
*delalloc_start_ret = oe_start;
*delalloc_end_ret = oe_end;
return true;
}
/*
* We have both unflushed delalloc (io_tree) and an ordered extent.
* If the ranges are adjacent returned a combined range, otherwise
* return the leftmost range.
*/
if (oe_start < *delalloc_start_ret) {
if (oe_end < *delalloc_start_ret)
*delalloc_end_ret = oe_end;
*delalloc_start_ret = oe_start;
} else if (*delalloc_end_ret + 1 == oe_start) {
*delalloc_end_ret = oe_end;
}
return true;
}
/*
* Check if there's delalloc in a given range.
*
* @inode: The inode.
* @start: The start offset of the range. It does not need to be
* sector size aligned.
* @end: The end offset (inclusive value) of the search range.
* It does not need to be sector size aligned.
* @cached_state: Extent state record used for speeding up delalloc
* searches in the inode's io_tree. Can be NULL.
* @delalloc_start_ret: Output argument, set to the start offset of the
* subrange found with delalloc (may not be sector size
* aligned).
* @delalloc_end_ret: Output argument, set to he end offset (inclusive value)
* of the subrange found with delalloc.
*
* Returns true if a subrange with delalloc is found within the given range, and
* if so it sets @delalloc_start_ret and @delalloc_end_ret with the start and
* end offsets of the subrange.
*/
bool btrfs_find_delalloc_in_range(struct btrfs_inode *inode, u64 start, u64 end,
struct extent_state **cached_state,
u64 *delalloc_start_ret, u64 *delalloc_end_ret)
{
u64 cur_offset = round_down(start, inode->root->fs_info->sectorsize);
u64 prev_delalloc_end = 0;
bool search_io_tree = true;
bool ret = false;
while (cur_offset < end) {
u64 delalloc_start;
u64 delalloc_end;
bool delalloc;
delalloc = find_delalloc_subrange(inode, cur_offset, end,
cached_state, &search_io_tree,
&delalloc_start,
&delalloc_end);
if (!delalloc)
break;
if (prev_delalloc_end == 0) {
/* First subrange found. */
*delalloc_start_ret = max(delalloc_start, start);
*delalloc_end_ret = delalloc_end;
ret = true;
} else if (delalloc_start == prev_delalloc_end + 1) {
/* Subrange adjacent to the previous one, merge them. */
*delalloc_end_ret = delalloc_end;
} else {
/* Subrange not adjacent to the previous one, exit. */
break;
}
prev_delalloc_end = delalloc_end;
cur_offset = delalloc_end + 1;
cond_resched();
}
return ret;
}
/*
* Check if there's a hole or delalloc range in a range representing a hole (or
* prealloc extent) found in the inode's subvolume btree.
*
* @inode: The inode.
* @whence: Seek mode (SEEK_DATA or SEEK_HOLE).
* @start: Start offset of the hole region. It does not need to be sector
* size aligned.
* @end: End offset (inclusive value) of the hole region. It does not
* need to be sector size aligned.
* @start_ret: Return parameter, used to set the start of the subrange in the
* hole that matches the search criteria (seek mode), if such
* subrange is found (return value of the function is true).
* The value returned here may not be sector size aligned.
*
* Returns true if a subrange matching the given seek mode is found, and if one
* is found, it updates @start_ret with the start of the subrange.
*/
static bool find_desired_extent_in_hole(struct btrfs_inode *inode, int whence,
struct extent_state **cached_state,
u64 start, u64 end, u64 *start_ret)
{
u64 delalloc_start;
u64 delalloc_end;
bool delalloc;
delalloc = btrfs_find_delalloc_in_range(inode, start, end, cached_state,
&delalloc_start, &delalloc_end);
if (delalloc && whence == SEEK_DATA) {
*start_ret = delalloc_start;
return true;
}
if (delalloc && whence == SEEK_HOLE) {
/*
* We found delalloc but it starts after out start offset. So we
* have a hole between our start offset and the delalloc start.
*/
if (start < delalloc_start) {
*start_ret = start;
return true;
}
/*
* Delalloc range starts at our start offset.
* If the delalloc range's length is smaller than our range,
* then it means we have a hole that starts where the delalloc
* subrange ends.
*/
if (delalloc_end < end) {
*start_ret = delalloc_end + 1;
return true;
}
/* There's delalloc for the whole range. */
return false;
}
if (!delalloc && whence == SEEK_HOLE) {
*start_ret = start;
return true;
}
/*
* No delalloc in the range and we are seeking for data. The caller has
* to iterate to the next extent item in the subvolume btree.
*/
return false;
}
static loff_t find_desired_extent(struct file *file, loff_t offset, int whence)
{
struct btrfs_inode *inode = BTRFS_I(file->f_mapping->host);
struct btrfs_file_private *private = file->private_data;
struct btrfs_fs_info *fs_info = inode->root->fs_info;
struct extent_state *cached_state = NULL;
struct extent_state **delalloc_cached_state;
const loff_t i_size = i_size_read(&inode->vfs_inode);
const u64 ino = btrfs_ino(inode);
struct btrfs_root *root = inode->root;
struct btrfs_path *path;
struct btrfs_key key;
u64 last_extent_end;
u64 lockstart;
u64 lockend;
u64 start;
int ret;
bool found = false;
if (i_size == 0 || offset >= i_size)
return -ENXIO;
/*
* Quick path. If the inode has no prealloc extents and its number of
* bytes used matches its i_size, then it can not have holes.
*/
if (whence == SEEK_HOLE &&
!(inode->flags & BTRFS_INODE_PREALLOC) &&
inode_get_bytes(&inode->vfs_inode) == i_size)
return i_size;
if (!private) {
private = kzalloc(sizeof(*private), GFP_KERNEL);
/*
* No worries if memory allocation failed.
* The private structure is used only for speeding up multiple
* lseek SEEK_HOLE/DATA calls to a file when there's delalloc,
* so everything will still be correct.
*/
file->private_data = private;
}
if (private)
delalloc_cached_state = &private->llseek_cached_state;
else
delalloc_cached_state = NULL;
/*
* offset can be negative, in this case we start finding DATA/HOLE from
* the very start of the file.
*/
start = max_t(loff_t, 0, offset);
lockstart = round_down(start, fs_info->sectorsize);
lockend = round_up(i_size, fs_info->sectorsize);
if (lockend <= lockstart)
lockend = lockstart + fs_info->sectorsize;
lockend--;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
path->reada = READA_FORWARD;
key.objectid = ino;
key.type = BTRFS_EXTENT_DATA_KEY;
key.offset = start;
last_extent_end = lockstart;
lock_extent(&inode->io_tree, lockstart, lockend, &cached_state);
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
if (ret < 0) {
goto out;
} else if (ret > 0 && path->slots[0] > 0) {
btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0] - 1);
if (key.objectid == ino && key.type == BTRFS_EXTENT_DATA_KEY)
path->slots[0]--;
}
while (start < i_size) {
struct extent_buffer *leaf = path->nodes[0];
struct btrfs_file_extent_item *extent;
u64 extent_end;
if (path->slots[0] >= btrfs_header_nritems(leaf)) {
ret = btrfs_next_leaf(root, path);
if (ret < 0)
goto out;
else if (ret > 0)
break;
leaf = path->nodes[0];
}
btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
if (key.objectid != ino || key.type != BTRFS_EXTENT_DATA_KEY)
break;
extent_end = btrfs_file_extent_end(path);
/*
* In the first iteration we may have a slot that points to an
* extent that ends before our start offset, so skip it.
*/
if (extent_end <= start) {
path->slots[0]++;
continue;
}
/* We have an implicit hole, NO_HOLES feature is likely set. */
if (last_extent_end < key.offset) {
u64 search_start = last_extent_end;
u64 found_start;
/*
* First iteration, @start matches @offset and it's
* within the hole.
*/
if (start == offset)
search_start = offset;
found = find_desired_extent_in_hole(inode, whence,
delalloc_cached_state,
search_start,
key.offset - 1,
&found_start);
if (found) {
start = found_start;
break;
}
/*
* Didn't find data or a hole (due to delalloc) in the
* implicit hole range, so need to analyze the extent.
*/
}
extent = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_file_extent_item);
if (btrfs_file_extent_disk_bytenr(leaf, extent) == 0 ||
btrfs_file_extent_type(leaf, extent) ==
BTRFS_FILE_EXTENT_PREALLOC) {
/*
* Explicit hole or prealloc extent, search for delalloc.
* A prealloc extent is treated like a hole.
*/
u64 search_start = key.offset;
u64 found_start;
/*
* First iteration, @start matches @offset and it's
* within the hole.
*/
if (start == offset)
search_start = offset;
found = find_desired_extent_in_hole(inode, whence,
delalloc_cached_state,
search_start,
extent_end - 1,
&found_start);
if (found) {
start = found_start;
break;
}
/*
* Didn't find data or a hole (due to delalloc) in the
* implicit hole range, so need to analyze the next
* extent item.
*/
} else {
/*
* Found a regular or inline extent.
* If we are seeking for data, adjust the start offset
* and stop, we're done.
*/
if (whence == SEEK_DATA) {
start = max_t(u64, key.offset, offset);
found = true;
break;
}
/*
* Else, we are seeking for a hole, check the next file
* extent item.
*/
}
start = extent_end;
last_extent_end = extent_end;
path->slots[0]++;
if (fatal_signal_pending(current)) {
ret = -EINTR;
goto out;
}
cond_resched();
}
/* We have an implicit hole from the last extent found up to i_size. */
if (!found && start < i_size) {
found = find_desired_extent_in_hole(inode, whence,
delalloc_cached_state, start,
i_size - 1, &start);
if (!found)
start = i_size;
}
out:
unlock_extent(&inode->io_tree, lockstart, lockend, &cached_state);
btrfs_free_path(path);
if (ret < 0)
return ret;
if (whence == SEEK_DATA && start >= i_size)
return -ENXIO;
return min_t(loff_t, start, i_size);
}
static loff_t btrfs_file_llseek(struct file *file, loff_t offset, int whence)
{
struct inode *inode = file->f_mapping->host;
switch (whence) {
default:
return generic_file_llseek(file, offset, whence);
case SEEK_DATA:
case SEEK_HOLE:
btrfs_inode_lock(BTRFS_I(inode), BTRFS_ILOCK_SHARED);
offset = find_desired_extent(file, offset, whence);
btrfs_inode_unlock(BTRFS_I(inode), BTRFS_ILOCK_SHARED);
break;
}
if (offset < 0)
return offset;
return vfs_setpos(file, offset, inode->i_sb->s_maxbytes);
}
static int btrfs_file_open(struct inode *inode, struct file *filp)
{
int ret;
filp->f_mode |= FMODE_NOWAIT | FMODE_BUF_RASYNC | FMODE_BUF_WASYNC;
ret = fsverity_file_open(inode, filp);
if (ret)
return ret;
return generic_file_open(inode, filp);
}
static int check_direct_read(struct btrfs_fs_info *fs_info,
const struct iov_iter *iter, loff_t offset)
{
int ret;
int i, seg;
ret = check_direct_IO(fs_info, iter, offset);
if (ret < 0)
return ret;
if (!iter_is_iovec(iter))
return 0;
for (seg = 0; seg < iter->nr_segs; seg++)
for (i = seg + 1; i < iter->nr_segs; i++)
if (iter->iov[seg].iov_base == iter->iov[i].iov_base)
return -EINVAL;
return 0;
}
static ssize_t btrfs_direct_read(struct kiocb *iocb, struct iov_iter *to)
{
struct inode *inode = file_inode(iocb->ki_filp);
size_t prev_left = 0;
ssize_t read = 0;
ssize_t ret;
if (fsverity_active(inode))
return 0;
if (check_direct_read(btrfs_sb(inode->i_sb), to, iocb->ki_pos))
return 0;
btrfs_inode_lock(BTRFS_I(inode), BTRFS_ILOCK_SHARED);
again:
/*
* This is similar to what we do for direct IO writes, see the comment
* at btrfs_direct_write(), but we also disable page faults in addition
* to disabling them only at the iov_iter level. This is because when
* reading from a hole or prealloc extent, iomap calls iov_iter_zero(),
* which can still trigger page fault ins despite having set ->nofault
* to true of our 'to' iov_iter.
*
* The difference to direct IO writes is that we deadlock when trying
* to lock the extent range in the inode's tree during he page reads
* triggered by the fault in (while for writes it is due to waiting for
* our own ordered extent). This is because for direct IO reads,
* btrfs_dio_iomap_begin() returns with the extent range locked, which
* is only unlocked in the endio callback (end_bio_extent_readpage()).
*/
pagefault_disable();
to->nofault = true;
ret = btrfs_dio_read(iocb, to, read);
to->nofault = false;
pagefault_enable();
/* No increment (+=) because iomap returns a cumulative value. */
if (ret > 0)
read = ret;
if (iov_iter_count(to) > 0 && (ret == -EFAULT || ret > 0)) {
const size_t left = iov_iter_count(to);
if (left == prev_left) {
/*
* We didn't make any progress since the last attempt,
* fallback to a buffered read for the remainder of the
* range. This is just to avoid any possibility of looping
* for too long.
*/
ret = read;
} else {
/*
* We made some progress since the last retry or this is
* the first time we are retrying. Fault in as many pages
* as possible and retry.
*/
fault_in_iov_iter_writeable(to, left);
prev_left = left;
goto again;
}
}
btrfs_inode_unlock(BTRFS_I(inode), BTRFS_ILOCK_SHARED);
return ret < 0 ? ret : read;
}
static ssize_t btrfs_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
{
ssize_t ret = 0;
if (iocb->ki_flags & IOCB_DIRECT) {
ret = btrfs_direct_read(iocb, to);
if (ret < 0 || !iov_iter_count(to) ||
iocb->ki_pos >= i_size_read(file_inode(iocb->ki_filp)))
return ret;
}
return filemap_read(iocb, to, ret);
}
const struct file_operations btrfs_file_operations = {
.llseek = btrfs_file_llseek,
.read_iter = btrfs_file_read_iter,
.splice_read = generic_file_splice_read,
.write_iter = btrfs_file_write_iter,
.splice_write = iter_file_splice_write,
.mmap = btrfs_file_mmap,
.open = btrfs_file_open,
.release = btrfs_release_file,
.get_unmapped_area = thp_get_unmapped_area,
.fsync = btrfs_sync_file,
.fallocate = btrfs_fallocate,
.unlocked_ioctl = btrfs_ioctl,
#ifdef CONFIG_COMPAT
.compat_ioctl = btrfs_compat_ioctl,
#endif
.remap_file_range = btrfs_remap_file_range,
};
int btrfs_fdatawrite_range(struct inode *inode, loff_t start, loff_t end)
{
int ret;
/*
* So with compression we will find and lock a dirty page and clear the
* first one as dirty, setup an async extent, and immediately return
* with the entire range locked but with nobody actually marked with
* writeback. So we can't just filemap_write_and_wait_range() and
* expect it to work since it will just kick off a thread to do the
* actual work. So we need to call filemap_fdatawrite_range _again_
* since it will wait on the page lock, which won't be unlocked until
* after the pages have been marked as writeback and so we're good to go
* from there. We have to do this otherwise we'll miss the ordered
* extents and that results in badness. Please Josef, do not think you
* know better and pull this out at some point in the future, it is
* right and you are wrong.
*/
ret = filemap_fdatawrite_range(inode->i_mapping, start, end);
if (!ret && test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
&BTRFS_I(inode)->runtime_flags))
ret = filemap_fdatawrite_range(inode->i_mapping, start, end);
return ret;
}
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