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btrfs: Add check to avoid cleanup roots already in fs_info->dead_roots.

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Current btrfs_orphan_cleanup will also cleanup roots which is already in
fs_info->dead_roots without protection.
This will have conditional race with fs_info->cleaner_kthread.

This patch will use refs in root->root_item to detect roots in
dead_roots and avoid conflicts.

Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
This commit is contained in:
Qu Wenruo 2014-04-22 17:13:51 +08:00 committed by Chris Mason
parent 21c7e75654
commit 65d33fd7a6
1 changed files with 31 additions and 8 deletions
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39
fs/btrfs/disk-io.c
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@ -3534,28 +3534,51 @@ int btrfs_cleanup_fs_roots(struct btrfs_fs_info *fs_info)
{ {
u64 root_objectid = 0; u64 root_objectid = 0;
struct btrfs_root *gang[8]; struct btrfs_root *gang[8];
int i; int i = 0;
int ret; int err = 0;
unsigned int ret = 0;
int index;
while (1) { while (1) {
index = srcu_read_lock(&fs_info->subvol_srcu);
ret = radix_tree_gang_lookup(&fs_info->fs_roots_radix, ret = radix_tree_gang_lookup(&fs_info->fs_roots_radix,
(void **)gang, root_objectid, (void **)gang, root_objectid,
ARRAY_SIZE(gang)); ARRAY_SIZE(gang));
if (!ret) if (!ret) {
srcu_read_unlock(&fs_info->subvol_srcu, index);
break; break;
}
root_objectid = gang[ret - 1]->root_key.objectid + 1; root_objectid = gang[ret - 1]->root_key.objectid + 1;
for (i = 0; i < ret; i++) {
int err;
for (i = 0; i < ret; i++) {
/* Avoid to grab roots in dead_roots */
if (btrfs_root_refs(&gang[i]->root_item) == 0) {
gang[i] = NULL;
continue;
}
/* grab all the search result for later use */
gang[i] = btrfs_grab_fs_root(gang[i]);
}
srcu_read_unlock(&fs_info->subvol_srcu, index);
for (i = 0; i < ret; i++) {
if (!gang[i])
continue;
root_objectid = gang[i]->root_key.objectid; root_objectid = gang[i]->root_key.objectid;
err = btrfs_orphan_cleanup(gang[i]); err = btrfs_orphan_cleanup(gang[i]);
if (err) if (err)
return err; break;
btrfs_put_fs_root(gang[i]);
} }
root_objectid++; root_objectid++;
} }
return 0;
/* release the uncleaned roots due to error */
for (; i < ret; i++) {
if (gang[i])
btrfs_put_fs_root(gang[i]);
}
return err;
} }
int btrfs_commit_super(struct btrfs_root *root) int btrfs_commit_super(struct btrfs_root *root)