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authorLiu Bo <liubo2009@cn.fujitsu.com>2012-06-29 03:58:49 -0600
committerChris Mason <chris.mason@fusionio.com>2012-07-23 16:27:58 -0400
commitb9ca0664dc806ba70587f6f3202b60dc736cd6e5 (patch)
treefd40828d3af0ba3b16e1e9231c406d6a6b1bace4 /fs/btrfs
parente54bfa31044d602a57d4e190f6d1c3763ea76bfe (diff)
Btrfs: do not set subvolume flags in readonly mode
$ mkfs.btrfs /dev/sdb7 $ btrfstune -S1 /dev/sdb7 $ mount /dev/sdb7 /mnt/btrfs mount: block device /dev/sdb7 is write-protected, mounting read-only $ btrfs dev add /dev/sdb8 /mnt/btrfs/ Now we get a btrfs in which mnt flags has readonly but sb flags does not. So for those ioctls that only check sb flags with MS_RDONLY, it is going to be a problem. Setting subvolume flags is such an ioctl, we should use mnt_want_write_file() to check RO flags. Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com>
Diffstat (limited to 'fs/btrfs')
-rw-r--r--fs/btrfs/ioctl.c42
1 files changed, 28 insertions, 14 deletions
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 13ed1c9534cc..17facea6a51c 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -1521,29 +1521,40 @@ static noinline int btrfs_ioctl_subvol_setflags(struct file *file,
u64 flags;
int ret = 0;
- if (root->fs_info->sb->s_flags & MS_RDONLY)
- return -EROFS;
+ ret = mnt_want_write_file(file);
+ if (ret)
+ goto out;
- if (btrfs_ino(inode) != BTRFS_FIRST_FREE_OBJECTID)
- return -EINVAL;
+ if (btrfs_ino(inode) != BTRFS_FIRST_FREE_OBJECTID) {
+ ret = -EINVAL;
+ goto out_drop_write;
+ }
- if (copy_from_user(&flags, arg, sizeof(flags)))
- return -EFAULT;
+ if (copy_from_user(&flags, arg, sizeof(flags))) {
+ ret = -EFAULT;
+ goto out_drop_write;
+ }
- if (flags & BTRFS_SUBVOL_CREATE_ASYNC)
- return -EINVAL;
+ if (flags & BTRFS_SUBVOL_CREATE_ASYNC) {
+ ret = -EINVAL;
+ goto out_drop_write;
+ }
- if (flags & ~BTRFS_SUBVOL_RDONLY)
- return -EOPNOTSUPP;
+ if (flags & ~BTRFS_SUBVOL_RDONLY) {
+ ret = -EOPNOTSUPP;
+ goto out_drop_write;
+ }
- if (!inode_owner_or_capable(inode))
- return -EACCES;
+ if (!inode_owner_or_capable(inode)) {
+ ret = -EACCES;
+ goto out_drop_write;
+ }
down_write(&root->fs_info->subvol_sem);
/* nothing to do */
if (!!(flags & BTRFS_SUBVOL_RDONLY) == btrfs_root_readonly(root))
- goto out;
+ goto out_drop_sem;
root_flags = btrfs_root_flags(&root->root_item);
if (flags & BTRFS_SUBVOL_RDONLY)
@@ -1566,8 +1577,11 @@ static noinline int btrfs_ioctl_subvol_setflags(struct file *file,
out_reset:
if (ret)
btrfs_set_root_flags(&root->root_item, root_flags);
-out:
+out_drop_sem:
up_write(&root->fs_info->subvol_sem);
+out_drop_write:
+ mnt_drop_write_file(file);
+out:
return ret;
}