6.6-stable review patch. If anyone has any objections, please let me know.
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From: Filipe Manana fdmanana@suse.com
[ Upstream commit fc746acb7aa9aeaa2cb5dcba449323319ba5c8eb ]
Whenever we need to send a command for the current inode, like sending writes, xattr updates, truncates, utimes, etc, we compute the inode's path each time, which implies doing some memory allocations and traversing the inode hierarchy to extract the name of the inode and each ancestor directory, and that implies doing lookups in the subvolume tree amongst other operations.
Most of the time, by far, the current inode's path doesn't change while we are processing it (like if we need to issue 100 write commands, the path remains the same and it's pointless to compute it 100 times).
To avoid this keep the current inode's path cached in the send context and invalidate it or update it whenever it's needed (after unlinks or renames).
A performance test, and its results, is mentioned in the next patch in the series (subject: "btrfs: send: avoid path allocation for the current inode when issuing commands").
Signed-off-by: Filipe Manana fdmanana@suse.com Reviewed-by: David Sterba dsterba@suse.com Signed-off-by: David Sterba dsterba@suse.com Stable-dep-of: 005b0a0c24e1 ("btrfs: send: use fallocate for hole punching with send stream v2") Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/btrfs/send.c | 53 ++++++++++++++++++++++++++++++++++++++++++++++++----- 1 file changed, 48 insertions(+), 5 deletions(-)
--- a/fs/btrfs/send.c +++ b/fs/btrfs/send.c @@ -179,6 +179,7 @@ struct send_ctx { u64 cur_inode_rdev; u64 cur_inode_last_extent; u64 cur_inode_next_write_offset; + struct fs_path cur_inode_path; bool cur_inode_new; bool cur_inode_new_gen; bool cur_inode_deleted; @@ -436,6 +437,14 @@ static void fs_path_reset(struct fs_path } }
+static void init_path(struct fs_path *p) +{ + p->reversed = 0; + p->buf = p->inline_buf; + p->buf_len = FS_PATH_INLINE_SIZE; + fs_path_reset(p); +} + static struct fs_path *fs_path_alloc(void) { struct fs_path *p; @@ -443,10 +452,7 @@ static struct fs_path *fs_path_alloc(voi p = kmalloc(sizeof(*p), GFP_KERNEL); if (!p) return NULL; - p->reversed = 0; - p->buf = p->inline_buf; - p->buf_len = FS_PATH_INLINE_SIZE; - fs_path_reset(p); + init_path(p); return p; }
@@ -624,6 +630,14 @@ static void fs_path_unreverse(struct fs_ p->reversed = 0; }
+static inline bool is_current_inode_path(const struct send_ctx *sctx, + const struct fs_path *path) +{ + const struct fs_path *cur = &sctx->cur_inode_path; + + return (strncmp(path->start, cur->start, fs_path_len(cur)) == 0); +} + static struct btrfs_path *alloc_path_for_send(void) { struct btrfs_path *path; @@ -2450,6 +2464,14 @@ static int get_cur_path(struct send_ctx u64 parent_inode = 0; u64 parent_gen = 0; int stop = 0; + const bool is_cur_inode = (ino == sctx->cur_ino && gen == sctx->cur_inode_gen); + + if (is_cur_inode && fs_path_len(&sctx->cur_inode_path) > 0) { + if (dest != &sctx->cur_inode_path) + return fs_path_copy(dest, &sctx->cur_inode_path); + + return 0; + }
name = fs_path_alloc(); if (!name) { @@ -2501,8 +2523,12 @@ static int get_cur_path(struct send_ctx
out: fs_path_free(name); - if (!ret) + if (!ret) { fs_path_unreverse(dest); + if (is_cur_inode && dest != &sctx->cur_inode_path) + ret = fs_path_copy(&sctx->cur_inode_path, dest); + } + return ret; }
@@ -3113,6 +3139,11 @@ static int orphanize_inode(struct send_c goto out;
ret = send_rename(sctx, path, orphan); + if (ret < 0) + goto out; + + if (ino == sctx->cur_ino && gen == sctx->cur_inode_gen) + ret = fs_path_copy(&sctx->cur_inode_path, orphan);
out: fs_path_free(orphan); @@ -4176,6 +4207,10 @@ static int rename_current_inode(struct s if (ret < 0) return ret;
+ ret = fs_path_copy(&sctx->cur_inode_path, new_path); + if (ret < 0) + return ret; + return fs_path_copy(current_path, new_path); }
@@ -4369,6 +4404,7 @@ static int process_recorded_refs(struct if (ret > 0) { orphanized_ancestor = true; fs_path_reset(valid_path); + fs_path_reset(&sctx->cur_inode_path); ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, valid_path); @@ -4568,6 +4604,8 @@ static int process_recorded_refs(struct ret = send_unlink(sctx, cur->full_path); if (ret < 0) goto out; + if (is_current_inode_path(sctx, cur->full_path)) + fs_path_reset(&sctx->cur_inode_path); } ret = dup_ref(cur, &check_dirs); if (ret < 0) @@ -6900,6 +6938,7 @@ static int changed_inode(struct send_ctx sctx->cur_inode_last_extent = (u64)-1; sctx->cur_inode_next_write_offset = 0; sctx->ignore_cur_inode = false; + fs_path_reset(&sctx->cur_inode_path);
/* * Set send_progress to current inode. This will tell all get_cur_xxx @@ -8190,6 +8229,7 @@ long btrfs_ioctl_send(struct inode *inod goto out; }
+ init_path(&sctx->cur_inode_path); INIT_LIST_HEAD(&sctx->new_refs); INIT_LIST_HEAD(&sctx->deleted_refs);
@@ -8475,6 +8515,9 @@ out: btrfs_lru_cache_clear(&sctx->dir_created_cache); btrfs_lru_cache_clear(&sctx->dir_utimes_cache);
+ if (sctx->cur_inode_path.buf != sctx->cur_inode_path.inline_buf) + kfree(sctx->cur_inode_path.buf); + kfree(sctx); }