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authorLiu Bo <liubo2009@cn.fujitsu.com>2012-06-29 05:58:49 -0400
committerChris Mason <chris.mason@fusionio.com>2012-07-23 16:27:58 -0400
commitb9ca0664dc806ba70587f6f3202b60dc736cd6e5 (patch)
treefd40828d3af0ba3b16e1e9231c406d6a6b1bace4 /fs/btrfs/ioctl.c
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/ioctl.c')
-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,
1521 u64 flags; 1521 u64 flags;
1522 int ret = 0; 1522 int ret = 0;
1523 1523
1524 if (root->fs_info->sb->s_flags & MS_RDONLY) 1524 ret = mnt_want_write_file(file);
1525 return -EROFS; 1525 if (ret)
1526 goto out;
1526 1527
1527 if (btrfs_ino(inode) != BTRFS_FIRST_FREE_OBJECTID) 1528 if (btrfs_ino(inode) != BTRFS_FIRST_FREE_OBJECTID) {
1528 return -EINVAL; 1529 ret = -EINVAL;
1530 goto out_drop_write;
1531 }
1529 1532
1530 if (copy_from_user(&flags, arg, sizeof(flags))) 1533 if (copy_from_user(&flags, arg, sizeof(flags))) {
1531 return -EFAULT; 1534 ret = -EFAULT;
1535 goto out_drop_write;
1536 }
1532 1537
1533 if (flags & BTRFS_SUBVOL_CREATE_ASYNC) 1538 if (flags & BTRFS_SUBVOL_CREATE_ASYNC) {
1534 return -EINVAL; 1539 ret = -EINVAL;
1540 goto out_drop_write;
1541 }
1535 1542
1536 if (flags & ~BTRFS_SUBVOL_RDONLY) 1543 if (flags & ~BTRFS_SUBVOL_RDONLY) {
1537 return -EOPNOTSUPP; 1544 ret = -EOPNOTSUPP;
1545 goto out_drop_write;
1546 }
1538 1547
1539 if (!inode_owner_or_capable(inode)) 1548 if (!inode_owner_or_capable(inode)) {
1540 return -EACCES; 1549 ret = -EACCES;
1550 goto out_drop_write;
1551 }
1541 1552
1542 down_write(&root->fs_info->subvol_sem); 1553 down_write(&root->fs_info->subvol_sem);
1543 1554
1544 /* nothing to do */ 1555 /* nothing to do */
1545 if (!!(flags & BTRFS_SUBVOL_RDONLY) == btrfs_root_readonly(root)) 1556 if (!!(flags & BTRFS_SUBVOL_RDONLY) == btrfs_root_readonly(root))
1546 goto out; 1557 goto out_drop_sem;
1547 1558
1548 root_flags = btrfs_root_flags(&root->root_item); 1559 root_flags = btrfs_root_flags(&root->root_item);
1549 if (flags & BTRFS_SUBVOL_RDONLY) 1560 if (flags & BTRFS_SUBVOL_RDONLY)
@@ -1566,8 +1577,11 @@ static noinline int btrfs_ioctl_subvol_setflags(struct file *file,
1566out_reset: 1577out_reset:
1567 if (ret) 1578 if (ret)
1568 btrfs_set_root_flags(&root->root_item, root_flags); 1579 btrfs_set_root_flags(&root->root_item, root_flags);
1569out: 1580out_drop_sem:
1570 up_write(&root->fs_info->subvol_sem); 1581 up_write(&root->fs_info->subvol_sem);
1582out_drop_write:
1583 mnt_drop_write_file(file);
1584out:
1571 return ret; 1585 return ret;
1572} 1586}
1573 1587