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authorLi Zefan <lizf@cn.fujitsu.com>2011-03-28 02:01:25 +0000
committerGreg Kroah-Hartman <gregkh@suse.de>2011-04-14 16:53:27 -0700
commite8a798830eb9b9f9285392c1ece79bfa7d29da32 (patch)
treea6452b027d74fb67246a06f409e50b04a67c7472 /fs
parent62fdb8668c631619251cff6d964556e0f67b8dcd (diff)
Btrfs: Fix uninitialized root flags for subvolumes
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 <philipp.andreas@gmail.com> Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Tested-by: Andreas Philipp <philipp.andreas@gmail.com> Signed-off-by: Chris Mason <chris.mason@oracle.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'fs')
-rw-r--r--fs/btrfs/ctree.h4
-rw-r--r--fs/btrfs/disk-io.c4
-rw-r--r--fs/btrfs/ioctl.c4
-rw-r--r--fs/btrfs/root-tree.c18
-rw-r--r--fs/btrfs/transaction.c1
5 files changed, 30 insertions, 1 deletions
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 9f806dd04c27..bb3c0f2ca667 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1182,6 +1182,8 @@ struct btrfs_root {
#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:
@@ -2183,6 +2185,8 @@ int btrfs_find_dead_roots(struct btrfs_root *root, u64 objectid);
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,
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 2b59201b955c..f4471883ba7b 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1145,8 +1145,10 @@ struct btrfs_root *btrfs_read_fs_root_no_radix(struct btrfs_root *tree_root,
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;
}
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 0bc577695061..3359aff5aeba 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -285,6 +285,10 @@ static noinline int create_subvol(struct btrfs_root *root,
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);
diff --git a/fs/btrfs/root-tree.c b/fs/btrfs/root-tree.c
index 67fa2d29d663..31742550b851 100644
--- a/fs/btrfs/root-tree.c
+++ b/fs/btrfs/root-tree.c
@@ -459,3 +459,21 @@ 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;
+ }
+}
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index b2acc79f1b34..b640fba11b48 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -777,6 +777,7 @@ static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
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);
key.objectid = objectid;
/* record when the snapshot was created in key.offset */