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btrfs: incremental send, improve rmdir performance for large directory 

Currently when checking if a directory can be deleted, we always check
if all its children have been processed.

Example: A directory with 2,000,000 files was deleted

original: 1994m57.071s
patch:       1m38.554s

[FIX]
Instead of checking all children on all calls to can_rmdir(), we keep
track of the directory index offset of the child last checked in the
last call to can_rmdir(), and then use it as the starting point for
future calls to can_rmdir().

Signed-off-by: Robbie Ko <robbieko@synology.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
[ update changelog ]
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Robbie Ko 2018-05-08 18:11:38 +08:00 committed by David Sterba
parent 35c8eda12f
commit 0f96f517dc
1 changed files with 22 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

31
fs/btrfs/send.c
View File

@ -235,6 +235,7 @@ struct orphan_dir_info {
struct rb_node node;
u64 ino;
u64 gen;
u64 last_dir_index_offset;
};
struct name_cache_entry {
@ -2861,6 +2862,7 @@ add_orphan_dir_info(struct send_ctx *sctx, u64 dir_ino)
return ERR_PTR(-ENOMEM);
odi->ino = dir_ino;
odi->gen = 0;
odi->last_dir_index_offset = 0;
rb_link_node(&odi->node, parent, p);
rb_insert_color(&odi->node, &sctx->orphan_dirs);
@ -2916,6 +2918,7 @@ static int can_rmdir(struct send_ctx *sctx, u64 dir, u64 dir_gen,
struct btrfs_key found_key;
struct btrfs_key loc;
struct btrfs_dir_item *di;
struct orphan_dir_info *odi = NULL;
/*
* Don't try to rmdir the top/root subvolume dir.
@ -2930,6 +2933,11 @@ static int can_rmdir(struct send_ctx *sctx, u64 dir, u64 dir_gen,
key.objectid = dir;
key.type = BTRFS_DIR_INDEX_KEY;
key.offset = 0;
odi = get_orphan_dir_info(sctx, dir);
if (odi)
key.offset = odi->last_dir_index_offset;
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
if (ret < 0)
goto out;
@ -2957,30 +2965,33 @@ static int can_rmdir(struct send_ctx *sctx, u64 dir, u64 dir_gen,
dm = get_waiting_dir_move(sctx, loc.objectid);
if (dm) {
struct orphan_dir_info *odi;
odi = add_orphan_dir_info(sctx, dir);
if (IS_ERR(odi)) {
ret = PTR_ERR(odi);
goto out;
}
odi->gen = dir_gen;
odi->last_dir_index_offset = found_key.offset;
dm->rmdir_ino = dir;
ret = 0;
goto out;
}
if (loc.objectid > send_progress) {
struct orphan_dir_info *odi;
odi = get_orphan_dir_info(sctx, dir);
free_orphan_dir_info(sctx, odi);
odi = add_orphan_dir_info(sctx, dir);
if (IS_ERR(odi)) {
ret = PTR_ERR(odi);
goto out;
}
odi->gen = dir_gen;
odi->last_dir_index_offset = found_key.offset;
ret = 0;
goto out;
}
path->slots[0]++;
}
free_orphan_dir_info(sctx, odi);
ret = 1;
@ -3258,13 +3269,16 @@ static int apply_dir_move(struct send_ctx *sctx, struct pending_dir_move *pm)
if (rmdir_ino) {
struct orphan_dir_info *odi;
u64 gen;
odi = get_orphan_dir_info(sctx, rmdir_ino);
if (!odi) {
/* already deleted */
goto finish;
}
ret = can_rmdir(sctx, rmdir_ino, odi->gen, sctx->cur_ino);
gen = odi->gen;
ret = can_rmdir(sctx, rmdir_ino, gen, sctx->cur_ino);
if (ret < 0)
goto out;
if (!ret)
@ -3275,13 +3289,12 @@ static int apply_dir_move(struct send_ctx *sctx, struct pending_dir_move *pm)
ret = -ENOMEM;
goto out;
}
ret = get_cur_path(sctx, rmdir_ino, odi->gen, name);
ret = get_cur_path(sctx, rmdir_ino, gen, name);
if (ret < 0)
goto out;
ret = send_rmdir(sctx, name);
if (ret < 0)
goto out;
free_orphan_dir_info(sctx, odi);
}
finish: