diff options
| author | Li Zefan | 2011-03-28 02:01:25 +0000 |
|---|---|---|
| committer | Chris Mason | 2011-04-05 01:20:24 -0400 |
| commit | 08fe4db170b4193603d9d31f40ebaf652d07ac9c (patch) | |
| tree | 2d0d2abe40b77266600653e399d4973a679716a9 /fs/btrfs/root-tree.c | |
| parent | adae52b94e18afa1f84fab67df2a8a872c2f5533 (diff) | |
Btrfs: Fix uninitialized root flags for subvolumes
root_item->flags and root_item->byte_limit are not initialized when
a subvolume is created. This bug is not revealed until we added
readonly snapshot support - now you mount a btrfs filesystem and you
may find the subvolumes in it are readonly.
To work around this problem, we steal a bit from root_item->inode_item->flags,
and use it to indicate if those fields have been properly initialized.
When we read a tree root from disk, we check if the bit is set, and if
not we'll set the flag and initialize the two fields of the root item.
Reported-by: Andreas Philipp <philipp.andreas@gmail.com>
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Tested-by: Andreas Philipp <philipp.andreas@gmail.com>
cc: stable@kernel.org
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Diffstat (limited to 'fs/btrfs/root-tree.c')
| -rw-r--r-- | fs/btrfs/root-tree.c | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/fs/btrfs/root-tree.c b/fs/btrfs/root-tree.c index 29b2d7c930eb..6928bff62daa 100644 --- a/fs/btrfs/root-tree.c +++ b/fs/btrfs/root-tree.c @@ -473,3 +473,21 @@ again: btrfs_free_path(path); return 0; } + +/* + * Old btrfs forgets to init root_item->flags and root_item->byte_limit + * for subvolumes. To work around this problem, we steal a bit from + * root_item->inode_item->flags, and use it to indicate if those fields + * have been properly initialized. + */ +void btrfs_check_and_init_root_item(struct btrfs_root_item *root_item) +{ + u64 inode_flags = le64_to_cpu(root_item->inode.flags); + + if (!(inode_flags & BTRFS_INODE_ROOT_ITEM_INIT)) { + inode_flags |= BTRFS_INODE_ROOT_ITEM_INIT; + root_item->inode.flags = cpu_to_le64(inode_flags); + root_item->flags = 0; + root_item->byte_limit = 0; + } +} |