[PATCH 29/44] btrfs: hold a ref on the root in btrfs_recover_relocation

Josef Bacik
2019-12-06T14:46:34Z

We look up the fs root in various places in here when recovering from a
crashed relcoation. Make sure we hold a ref on the root whenever we
look them up.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
---
fs/btrfs/relocation.c | 21 ++++++++++++++++++---
1 file changed, 18 insertions(+), 3 deletions(-)

diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index 4e455703439b..d40d145588f3 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -4542,6 +4542,10 @@ int btrfs_recover_relocation(struct btrfs_root *root)
if (btrfs_root_refs(&reloc_root->root_item) > 0) {
fs_root = read_fs_root(fs_info,
reloc_root->root_key.offset);
+ if (!btrfs_grab_fs_root(fs_root)) {
+ err = -ENOENT;
+ goto out;
+ }
if (IS_ERR(fs_root)) {
ret = PTR_ERR(fs_root);
if (ret != -ENOENT) {
@@ -4553,6 +4557,8 @@ int btrfs_recover_relocation(struct btrfs_root *root)
err = ret;
goto out;
}
+ } else {
+ btrfs_put_fs_root(fs_root);
}
}

@@ -4602,10 +4608,15 @@ int btrfs_recover_relocation(struct btrfs_root *root)
list_add_tail(&reloc_root->root_list, &reloc_roots);
goto out_free;
}
+ if (!btrfs_grab_fs_root(fs_root)) {
+ err = -ENOENT;
+ goto out_free;
+ }

err = __add_reloc_root(reloc_root);
BUG_ON(err < 0); /* -ENOMEM or logic error */
fs_root->reloc_root = reloc_root;
+ btrfs_put_fs_root(fs_root);
}

err = btrfs_commit_transaction(trans);
@@ -4637,10 +4648,14 @@ int btrfs_recover_relocation(struct btrfs_root *root)
if (err == 0) {
/* cleanup orphan inode in data relocation tree */
fs_root = read_fs_root(fs_info, BTRFS_DATA_RELOC_TREE_OBJECTID);
- if (IS_ERR(fs_root))
+ if (IS_ERR(fs_root)) {
err = PTR_ERR(fs_root);
- else
- err = btrfs_orphan_cleanup(fs_root);
+ } else {
+ if (btrfs_grab_fs_root(fs_root)) {
+ err = btrfs_orphan_cleanup(fs_root);
+ btrfs_put_fs_root(fs_root);
+ }
+ }
}
return err;
}
--
2.23.0