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authorJosef Bacik <josef@toxicpanda.com>2020-02-15 00:11:47 +0300
committerDavid Sterba <dsterba@suse.com>2020-03-23 19:02:00 +0300
commitc75e839414d3610e6487ae3145199c500d55f7f7 (patch)
tree68e609a6362c4f259afc2e107fffac94e743a126 /fs/btrfs/backref.c
parentefc3453494af78180ac00d9dd8391fd52c4a921e (diff)
downloadlinux-c75e839414d3610e6487ae3145199c500d55f7f7.tar.xz
btrfs: kill the subvol_srcu
Now that we have proper root ref counting everywhere we can kill the subvol_srcu. * removal of fs_info::subvol_srcu reduces size of fs_info by 1176 bytes * the refcount_t used for the references checks for accidental 0->1 in cases where the root lifetime would not be properly protected * there's a leak detector for roots to catch unfreed roots at umount time * SRCU served us well over the years but is was not a proper synchronization mechanism for some cases Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> [ update changelog ] Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs/btrfs/backref.c')
-rw-r--r--fs/btrfs/backref.c12
1 files changed, 1 insertions, 11 deletions
diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c
index f2728fb3ee8f..cd2d39b60be0 100644
--- a/fs/btrfs/backref.c
+++ b/fs/btrfs/backref.c
@@ -542,24 +542,19 @@ static int resolve_indirect_ref(struct btrfs_fs_info *fs_info,
int ret = 0;
int root_level;
int level = ref->level;
- int index;
struct btrfs_key search_key = ref->key_for_search;
root_key.objectid = ref->root_id;
root_key.type = BTRFS_ROOT_ITEM_KEY;
root_key.offset = (u64)-1;
- index = srcu_read_lock(&fs_info->subvol_srcu);
-
root = btrfs_get_fs_root(fs_info, &root_key, false);
if (IS_ERR(root)) {
- srcu_read_unlock(&fs_info->subvol_srcu, index);
ret = PTR_ERR(root);
goto out_free;
}
if (btrfs_is_testing(fs_info)) {
- srcu_read_unlock(&fs_info->subvol_srcu, index);
ret = -ENOENT;
goto out;
}
@@ -571,10 +566,8 @@ static int resolve_indirect_ref(struct btrfs_fs_info *fs_info,
else
root_level = btrfs_old_root_level(root, time_seq);
- if (root_level + 1 == level) {
- srcu_read_unlock(&fs_info->subvol_srcu, index);
+ if (root_level + 1 == level)
goto out;
- }
/*
* We can often find data backrefs with an offset that is too large
@@ -604,9 +597,6 @@ static int resolve_indirect_ref(struct btrfs_fs_info *fs_info,
else
ret = btrfs_search_old_slot(root, &search_key, path, time_seq);
- /* root node has been locked, we can release @subvol_srcu safely here */
- srcu_read_unlock(&fs_info->subvol_srcu, index);
-
btrfs_debug(fs_info,
"search slot in root %llu (level %d, ref count %d) returned %d for key (%llu %u %llu)",
ref->root_id, level, ref->count, ret,