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45c4102f0d
As of commit 1b53e51a4a ("btrfs: don't commit transaction for every
subvol create") we started to make any fsync after creating a subvolume
to fallback to a transaction commit if the fsync is performed in the
same transaction that was used to create the subvolume. This happens
with the following at ioctl.c:create_subvol():
$ cat fs/btrfs/ioctl.c
(...)
/* Tree log can't currently deal with an inode which is a new root. */
btrfs_set_log_full_commit(trans);
(...)
Note that the comment is misleading as the problem is not that fsync can
not deal with the root inode of a new root, but that we can not log any
inode that belongs to a root that was not yet persisted because that would
make log replay fail since the root doesn't exist at log replay time.
The above simply makes any fsync fallback to a full transaction commit if
it happens in the same transaction used to create the subvolume - even if
it's an inode that belongs to any other subvolume. This is a brute force
solution and it doesn't necessarily improve performance for every workload
out there - it just moves a full transaction commit from one place, the
subvolume creation, to another - an fsync for any inode.
Just improve on this by making the fallback to a transaction commit only
for an fsync against an inode of the new subvolume, or for the directory
that contains the dentry that points to the new subvolume (in case anyone
attempts to fsync the directory in the same transaction).
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
104 lines
3.7 KiB
C
104 lines
3.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Copyright (C) 2008 Oracle. All rights reserved.
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*/
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#ifndef BTRFS_TREE_LOG_H
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#define BTRFS_TREE_LOG_H
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#include <linux/list.h>
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#include <linux/fs.h>
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#include "messages.h"
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#include "ctree.h"
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#include "transaction.h"
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struct inode;
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struct dentry;
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struct btrfs_ordered_extent;
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struct btrfs_root;
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struct btrfs_trans_handle;
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/* return value for btrfs_log_dentry_safe that means we don't need to log it at all */
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#define BTRFS_NO_LOG_SYNC 256
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/*
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* We can't use the tree log for whatever reason, force a transaction commit.
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* We use a negative value because there are functions through the logging code
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* that need to return an error (< 0 value), false (0) or true (1). Any negative
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* value will do, as it will cause the log to be marked for a full sync.
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*/
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#define BTRFS_LOG_FORCE_COMMIT (-(MAX_ERRNO + 1))
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struct btrfs_log_ctx {
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int log_ret;
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int log_transid;
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bool log_new_dentries;
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bool logging_new_name;
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bool logging_new_delayed_dentries;
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/* Indicate if the inode being logged was logged before. */
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bool logged_before;
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struct btrfs_inode *inode;
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struct list_head list;
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/* Only used for fast fsyncs. */
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struct list_head ordered_extents;
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struct list_head conflict_inodes;
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int num_conflict_inodes;
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bool logging_conflict_inodes;
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/*
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* Used for fsyncs that need to copy items from the subvolume tree to
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* the log tree (full sync flag set or copy everything flag set) to
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* avoid allocating a temporary extent buffer while holding a lock on
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* an extent buffer of the subvolume tree and under the log transaction.
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* Also helps to avoid allocating and freeing a temporary extent buffer
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* in case we need to process multiple leaves from the subvolume tree.
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*/
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struct extent_buffer *scratch_eb;
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};
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void btrfs_init_log_ctx(struct btrfs_log_ctx *ctx, struct btrfs_inode *inode);
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void btrfs_init_log_ctx_scratch_eb(struct btrfs_log_ctx *ctx);
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void btrfs_release_log_ctx_extents(struct btrfs_log_ctx *ctx);
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static inline void btrfs_set_log_full_commit(struct btrfs_trans_handle *trans)
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{
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WRITE_ONCE(trans->fs_info->last_trans_log_full_commit, trans->transid);
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}
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static inline int btrfs_need_log_full_commit(struct btrfs_trans_handle *trans)
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{
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return READ_ONCE(trans->fs_info->last_trans_log_full_commit) ==
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trans->transid;
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}
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int btrfs_sync_log(struct btrfs_trans_handle *trans,
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struct btrfs_root *root, struct btrfs_log_ctx *ctx);
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int btrfs_free_log(struct btrfs_trans_handle *trans, struct btrfs_root *root);
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int btrfs_free_log_root_tree(struct btrfs_trans_handle *trans,
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struct btrfs_fs_info *fs_info);
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int btrfs_recover_log_trees(struct btrfs_root *tree_root);
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int btrfs_log_dentry_safe(struct btrfs_trans_handle *trans,
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struct dentry *dentry,
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struct btrfs_log_ctx *ctx);
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void btrfs_del_dir_entries_in_log(struct btrfs_trans_handle *trans,
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struct btrfs_root *root,
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const struct fscrypt_str *name,
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struct btrfs_inode *dir, u64 index);
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void btrfs_del_inode_ref_in_log(struct btrfs_trans_handle *trans,
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struct btrfs_root *root,
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const struct fscrypt_str *name,
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struct btrfs_inode *inode, u64 dirid);
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void btrfs_end_log_trans(struct btrfs_root *root);
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void btrfs_pin_log_trans(struct btrfs_root *root);
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void btrfs_record_unlink_dir(struct btrfs_trans_handle *trans,
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struct btrfs_inode *dir, struct btrfs_inode *inode,
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bool for_rename);
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void btrfs_record_snapshot_destroy(struct btrfs_trans_handle *trans,
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struct btrfs_inode *dir);
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void btrfs_record_new_subvolume(const struct btrfs_trans_handle *trans,
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struct btrfs_inode *dir);
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void btrfs_log_new_name(struct btrfs_trans_handle *trans,
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struct dentry *old_dentry, struct btrfs_inode *old_dir,
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u64 old_dir_index, struct dentry *parent);
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#endif
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