linux/fs/btrfs/btrfs_inode.h
Filipe Manana 528ee69712 btrfs: put initial index value of a directory in a constant
At btrfs_set_inode_index_count() we refer twice to the number 2 as the
initial index value for a directory (when it's empty), with a proper
comment explaining the reason for that value. In the next patch I'll
have to use that magic value in the directory logging code, so put
the value in a #define at btrfs_inode.h, to avoid hardcoding the
magic value again at tree-log.c.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-03-14 13:13:46 +01:00

428 lines
12 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
/*
* Copyright (C) 2007 Oracle. All rights reserved.
*/
#ifndef BTRFS_INODE_H
#define BTRFS_INODE_H
#include <linux/hash.h>
#include <linux/refcount.h>
#include "extent_map.h"
#include "extent_io.h"
#include "ordered-data.h"
#include "delayed-inode.h"
/*
* Since we search a directory based on f_pos (struct dir_context::pos) we have
* to start at 2 since '.' and '..' have f_pos of 0 and 1 respectively, so
* everybody else has to start at 2 (see btrfs_real_readdir() and dir_emit_dots()).
*/
#define BTRFS_DIR_START_INDEX 2
/*
* ordered_data_close is set by truncate when a file that used
* to have good data has been truncated to zero. When it is set
* the btrfs file release call will add this inode to the
* ordered operations list so that we make sure to flush out any
* new data the application may have written before commit.
*/
enum {
BTRFS_INODE_FLUSH_ON_CLOSE,
BTRFS_INODE_DUMMY,
BTRFS_INODE_IN_DEFRAG,
BTRFS_INODE_HAS_ASYNC_EXTENT,
/*
* Always set under the VFS' inode lock, otherwise it can cause races
* during fsync (we start as a fast fsync and then end up in a full
* fsync racing with ordered extent completion).
*/
BTRFS_INODE_NEEDS_FULL_SYNC,
BTRFS_INODE_COPY_EVERYTHING,
BTRFS_INODE_IN_DELALLOC_LIST,
BTRFS_INODE_HAS_PROPS,
BTRFS_INODE_SNAPSHOT_FLUSH,
/*
* Set and used when logging an inode and it serves to signal that an
* inode does not have xattrs, so subsequent fsyncs can avoid searching
* for xattrs to log. This bit must be cleared whenever a xattr is added
* to an inode.
*/
BTRFS_INODE_NO_XATTRS,
/*
* Set when we are in a context where we need to start a transaction and
* have dirty pages with the respective file range locked. This is to
* ensure that when reserving space for the transaction, if we are low
* on available space and need to flush delalloc, we will not flush
* delalloc for this inode, because that could result in a deadlock (on
* the file range, inode's io_tree).
*/
BTRFS_INODE_NO_DELALLOC_FLUSH,
/*
* Set when we are working on enabling verity for a file. Computing and
* writing the whole Merkle tree can take a while so we want to prevent
* races where two separate tasks attempt to simultaneously start verity
* on the same file.
*/
BTRFS_INODE_VERITY_IN_PROGRESS,
};
/* in memory btrfs inode */
struct btrfs_inode {
/* which subvolume this inode belongs to */
struct btrfs_root *root;
/* key used to find this inode on disk. This is used by the code
* to read in roots of subvolumes
*/
struct btrfs_key location;
/*
* Lock for counters and all fields used to determine if the inode is in
* the log or not (last_trans, last_sub_trans, last_log_commit,
* logged_trans), to access/update new_delalloc_bytes and to update the
* VFS' inode number of bytes used.
*/
spinlock_t lock;
/* the extent_tree has caches of all the extent mappings to disk */
struct extent_map_tree extent_tree;
/* the io_tree does range state (DIRTY, LOCKED etc) */
struct extent_io_tree io_tree;
/* special utility tree used to record which mirrors have already been
* tried when checksums fail for a given block
*/
struct extent_io_tree io_failure_tree;
/*
* Keep track of where the inode has extent items mapped in order to
* make sure the i_size adjustments are accurate
*/
struct extent_io_tree file_extent_tree;
/* held while logging the inode in tree-log.c */
struct mutex log_mutex;
/* used to order data wrt metadata */
struct btrfs_ordered_inode_tree ordered_tree;
/* list of all the delalloc inodes in the FS. There are times we need
* to write all the delalloc pages to disk, and this list is used
* to walk them all.
*/
struct list_head delalloc_inodes;
/* node for the red-black tree that links inodes in subvolume root */
struct rb_node rb_node;
unsigned long runtime_flags;
/* Keep track of who's O_SYNC/fsyncing currently */
atomic_t sync_writers;
/* full 64 bit generation number, struct vfs_inode doesn't have a big
* enough field for this.
*/
u64 generation;
/*
* transid of the trans_handle that last modified this inode
*/
u64 last_trans;
/*
* transid that last logged this inode
*/
u64 logged_trans;
/*
* log transid when this inode was last modified
*/
int last_sub_trans;
/* a local copy of root's last_log_commit */
int last_log_commit;
/*
* Total number of bytes pending delalloc, used by stat to calculate the
* real block usage of the file. This is used only for files.
*/
u64 delalloc_bytes;
union {
/*
* Total number of bytes pending delalloc that fall within a file
* range that is either a hole or beyond EOF (and no prealloc extent
* exists in the range). This is always <= delalloc_bytes and this
* is used only for files.
*/
u64 new_delalloc_bytes;
/*
* The offset of the last dir index key that was logged.
* This is used only for directories.
*/
u64 last_dir_index_offset;
};
/*
* total number of bytes pending defrag, used by stat to check whether
* it needs COW.
*/
u64 defrag_bytes;
/*
* the size of the file stored in the metadata on disk. data=ordered
* means the in-memory i_size might be larger than the size on disk
* because not all the blocks are written yet.
*/
u64 disk_i_size;
/*
* If this is a directory then index_cnt is the counter for the index
* number for new files that are created. For an empty directory, this
* must be initialized to BTRFS_DIR_START_INDEX.
*/
u64 index_cnt;
/* Cache the directory index number to speed the dir/file remove */
u64 dir_index;
/* the fsync log has some corner cases that mean we have to check
* directories to see if any unlinks have been done before
* the directory was logged. See tree-log.c for all the
* details
*/
u64 last_unlink_trans;
/*
* The id/generation of the last transaction where this inode was
* either the source or the destination of a clone/dedupe operation.
* Used when logging an inode to know if there are shared extents that
* need special care when logging checksum items, to avoid duplicate
* checksum items in a log (which can lead to a corruption where we end
* up with missing checksum ranges after log replay).
* Protected by the vfs inode lock.
*/
u64 last_reflink_trans;
/*
* Number of bytes outstanding that are going to need csums. This is
* used in ENOSPC accounting.
*/
u64 csum_bytes;
/* Backwards incompatible flags, lower half of inode_item::flags */
u32 flags;
/* Read-only compatibility flags, upper half of inode_item::flags */
u32 ro_flags;
/*
* Counters to keep track of the number of extent item's we may use due
* to delalloc and such. outstanding_extents is the number of extent
* items we think we'll end up using, and reserved_extents is the number
* of extent items we've reserved metadata for.
*/
unsigned outstanding_extents;
struct btrfs_block_rsv block_rsv;
/*
* Cached values of inode properties
*/
unsigned prop_compress; /* per-file compression algorithm */
/*
* Force compression on the file using the defrag ioctl, could be
* different from prop_compress and takes precedence if set
*/
unsigned defrag_compress;
struct btrfs_delayed_node *delayed_node;
/* File creation time. */
struct timespec64 i_otime;
/* Hook into fs_info->delayed_iputs */
struct list_head delayed_iput;
struct rw_semaphore i_mmap_lock;
struct inode vfs_inode;
};
static inline u32 btrfs_inode_sectorsize(const struct btrfs_inode *inode)
{
return inode->root->fs_info->sectorsize;
}
static inline struct btrfs_inode *BTRFS_I(const struct inode *inode)
{
return container_of(inode, struct btrfs_inode, vfs_inode);
}
static inline unsigned long btrfs_inode_hash(u64 objectid,
const struct btrfs_root *root)
{
u64 h = objectid ^ (root->root_key.objectid * GOLDEN_RATIO_PRIME);
#if BITS_PER_LONG == 32
h = (h >> 32) ^ (h & 0xffffffff);
#endif
return (unsigned long)h;
}
static inline void btrfs_insert_inode_hash(struct inode *inode)
{
unsigned long h = btrfs_inode_hash(inode->i_ino, BTRFS_I(inode)->root);
__insert_inode_hash(inode, h);
}
static inline u64 btrfs_ino(const struct btrfs_inode *inode)
{
u64 ino = inode->location.objectid;
/*
* !ino: btree_inode
* type == BTRFS_ROOT_ITEM_KEY: subvol dir
*/
if (!ino || inode->location.type == BTRFS_ROOT_ITEM_KEY)
ino = inode->vfs_inode.i_ino;
return ino;
}
static inline void btrfs_i_size_write(struct btrfs_inode *inode, u64 size)
{
i_size_write(&inode->vfs_inode, size);
inode->disk_i_size = size;
}
static inline bool btrfs_is_free_space_inode(struct btrfs_inode *inode)
{
struct btrfs_root *root = inode->root;
if (root == root->fs_info->tree_root &&
btrfs_ino(inode) != BTRFS_BTREE_INODE_OBJECTID)
return true;
if (inode->location.objectid == BTRFS_FREE_INO_OBJECTID)
return true;
return false;
}
static inline bool is_data_inode(struct inode *inode)
{
return btrfs_ino(BTRFS_I(inode)) != BTRFS_BTREE_INODE_OBJECTID;
}
static inline void btrfs_mod_outstanding_extents(struct btrfs_inode *inode,
int mod)
{
lockdep_assert_held(&inode->lock);
inode->outstanding_extents += mod;
if (btrfs_is_free_space_inode(inode))
return;
trace_btrfs_inode_mod_outstanding_extents(inode->root, btrfs_ino(inode),
mod);
}
/*
* Called every time after doing a buffered, direct IO or memory mapped write.
*
* This is to ensure that if we write to a file that was previously fsynced in
* the current transaction, then try to fsync it again in the same transaction,
* we will know that there were changes in the file and that it needs to be
* logged.
*/
static inline void btrfs_set_inode_last_sub_trans(struct btrfs_inode *inode)
{
spin_lock(&inode->lock);
inode->last_sub_trans = inode->root->log_transid;
spin_unlock(&inode->lock);
}
static inline bool btrfs_inode_in_log(struct btrfs_inode *inode, u64 generation)
{
bool ret = false;
spin_lock(&inode->lock);
if (inode->logged_trans == generation &&
inode->last_sub_trans <= inode->last_log_commit &&
inode->last_sub_trans <= inode->root->last_log_commit)
ret = true;
spin_unlock(&inode->lock);
return ret;
}
struct btrfs_dio_private {
struct inode *inode;
/*
* Since DIO can use anonymous page, we cannot use page_offset() to
* grab the file offset, thus need a dedicated member for file offset.
*/
u64 file_offset;
u64 disk_bytenr;
/* Used for bio::bi_size */
u32 bytes;
/*
* References to this structure. There is one reference per in-flight
* bio plus one while we're still setting up.
*/
refcount_t refs;
/* dio_bio came from fs/direct-io.c */
struct bio *dio_bio;
/* Array of checksums */
u8 csums[];
};
/*
* btrfs_inode_item stores flags in a u64, btrfs_inode stores them in two
* separate u32s. These two functions convert between the two representations.
*/
static inline u64 btrfs_inode_combine_flags(u32 flags, u32 ro_flags)
{
return (flags | ((u64)ro_flags << 32));
}
static inline void btrfs_inode_split_flags(u64 inode_item_flags,
u32 *flags, u32 *ro_flags)
{
*flags = (u32)inode_item_flags;
*ro_flags = (u32)(inode_item_flags >> 32);
}
/* Array of bytes with variable length, hexadecimal format 0x1234 */
#define CSUM_FMT "0x%*phN"
#define CSUM_FMT_VALUE(size, bytes) size, bytes
static inline void btrfs_print_data_csum_error(struct btrfs_inode *inode,
u64 logical_start, u8 *csum, u8 *csum_expected, int mirror_num)
{
struct btrfs_root *root = inode->root;
const u32 csum_size = root->fs_info->csum_size;
/* Output minus objectid, which is more meaningful */
if (root->root_key.objectid >= BTRFS_LAST_FREE_OBJECTID)
btrfs_warn_rl(root->fs_info,
"csum failed root %lld ino %lld off %llu csum " CSUM_FMT " expected csum " CSUM_FMT " mirror %d",
root->root_key.objectid, btrfs_ino(inode),
logical_start,
CSUM_FMT_VALUE(csum_size, csum),
CSUM_FMT_VALUE(csum_size, csum_expected),
mirror_num);
else
btrfs_warn_rl(root->fs_info,
"csum failed root %llu ino %llu off %llu csum " CSUM_FMT " expected csum " CSUM_FMT " mirror %d",
root->root_key.objectid, btrfs_ino(inode),
logical_start,
CSUM_FMT_VALUE(csum_size, csum),
CSUM_FMT_VALUE(csum_size, csum_expected),
mirror_num);
}
#endif