2.6.38-stable review patch. If anyone has any objections, please let us know.
------------------ From: Li Zefan <[email protected]> commit 08fe4db170b4193603d9d31f40ebaf652d07ac9c upstream. 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 <[email protected]> Signed-off-by: Li Zefan <[email protected]> Tested-by: Andreas Philipp <[email protected]> Signed-off-by: Chris Mason <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- fs/btrfs/ctree.h | 4 ++++ fs/btrfs/disk-io.c | 4 +++- fs/btrfs/ioctl.c | 4 ++++ fs/btrfs/root-tree.c | 18 ++++++++++++++++++ fs/btrfs/transaction.c | 1 + 5 files changed, 30 insertions(+), 1 deletion(-) --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -1284,6 +1284,8 @@ struct btrfs_root { #define BTRFS_INODE_NOATIME (1 << 9) #define BTRFS_INODE_DIRSYNC (1 << 10) +#define BTRFS_INODE_ROOT_ITEM_INIT (1 << 31) + /* some macros to generate set/get funcs for the struct fields. This * assumes there is a lefoo_to_cpu for every type, so lets make a simple * one for u8: @@ -2355,6 +2357,8 @@ int btrfs_find_dead_roots(struct btrfs_r int btrfs_find_orphan_roots(struct btrfs_root *tree_root); int btrfs_set_root_node(struct btrfs_root_item *item, struct extent_buffer *node); +void btrfs_check_and_init_root_item(struct btrfs_root_item *item); + /* dir-item.c */ int btrfs_insert_dir_item(struct btrfs_trans_handle *trans, struct btrfs_root *root, const char *name, --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -1184,8 +1184,10 @@ struct btrfs_root *btrfs_read_fs_root_no root->commit_root = btrfs_root_node(root); BUG_ON(!root->node); out: - if (location->objectid != BTRFS_TREE_LOG_OBJECTID) + if (location->objectid != BTRFS_TREE_LOG_OBJECTID) { root->ref_cows = 1; + btrfs_check_and_init_root_item(&root->root_item); + } return root; } --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -294,6 +294,10 @@ static noinline int create_subvol(struct inode_item->nbytes = cpu_to_le64(root->leafsize); inode_item->mode = cpu_to_le32(S_IFDIR | 0755); + root_item.flags = 0; + root_item.byte_limit = 0; + inode_item->flags = cpu_to_le64(BTRFS_INODE_ROOT_ITEM_INIT); + btrfs_set_root_bytenr(&root_item, leaf->start); btrfs_set_root_generation(&root_item, trans->transid); btrfs_set_root_level(&root_item, 0); --- a/fs/btrfs/root-tree.c +++ b/fs/btrfs/root-tree.c @@ -471,3 +471,21 @@ 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; + } +} --- a/fs/btrfs/transaction.c +++ b/fs/btrfs/transaction.c @@ -970,6 +970,7 @@ static noinline int create_pending_snaps record_root_in_trans(trans, root); btrfs_set_root_last_snapshot(&root->root_item, trans->transid); memcpy(new_root_item, &root->root_item, sizeof(*new_root_item)); + btrfs_check_and_init_root_item(new_root_item); root_flags = btrfs_root_flags(new_root_item); if (pending->readonly) _______________________________________________ stable mailing list [email protected] http://linux.kernel.org/mailman/listinfo/stable
