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| author | Miao Xie <miaox@cn.fujitsu.com> | 2012-11-26 08:44:50 +0000 |
|---|---|---|
| committer | Chris Mason <chris.mason@fusionio.com> | 2012-12-16 20:46:09 -0500 |
| commit | da24927b1e1925da5c1885cb483231dabe027e15 (patch) | |
| tree | 6d28cb9342d4251a8eb0116f79ee3816843c9a61 /fs/btrfs/ioctl.c | |
| parent | 198605a8e2077f174c9834c97b836f535e4e56dd (diff) | |
| download | linux-da24927b1e1925da5c1885cb483231dabe027e15.tar.gz linux-da24927b1e1925da5c1885cb483231dabe027e15.tar.bz2 linux-da24927b1e1925da5c1885cb483231dabe027e15.zip | |
Btrfs: get write access when removing a device
Steps to reproduce:
# mkfs.btrfs -d single -m single <disk0> <disk1>
# mount -o ro <disk0> <mnt0>
# mount -o ro <disk0> <mnt1>
# mount -o remount,rw <mnt0>
# umount <mnt0>
# btrfs device delete <disk1> <mnt1>
We can remove a device from a R/O filesystem. The reason is that we just check
the R/O flag of the super block object. It is not enough, because the kernel
may set the R/O flag only for the mount point. We need invoke
mnt_want_write_file()
to do a full check.
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
Diffstat (limited to 'fs/btrfs/ioctl.c')
| -rw-r--r-- | fs/btrfs/ioctl.c | 12 |
1 files changed, 8 insertions, 4 deletions
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index 2be49b4c82d6..ee36009f8aa1 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -2270,20 +2270,23 @@ out: return ret; } -static long btrfs_ioctl_rm_dev(struct btrfs_root *root, void __user *arg) +static long btrfs_ioctl_rm_dev(struct file *file, void __user *arg) { + struct btrfs_root *root = BTRFS_I(fdentry(file)->d_inode)->root; struct btrfs_ioctl_vol_args *vol_args; int ret; if (!capable(CAP_SYS_ADMIN)) return -EPERM; - if (root->fs_info->sb->s_flags & MS_RDONLY) - return -EROFS; + ret = mnt_want_write_file(file); + if (ret) + return ret; if (atomic_xchg(&root->fs_info->mutually_exclusive_operation_running, 1)) { pr_info("btrfs: dev add/delete/balance/replace/resize operation in progress\n"); + mnt_drop_write_file(file); return -EINPROGRESS; } @@ -2300,6 +2303,7 @@ static long btrfs_ioctl_rm_dev(struct btrfs_root *root, void __user *arg) kfree(vol_args); out: mutex_unlock(&root->fs_info->volume_mutex); + mnt_drop_write_file(file); atomic_set(&root->fs_info->mutually_exclusive_operation_running, 0); return ret; } @@ -3842,7 +3846,7 @@ long btrfs_ioctl(struct file *file, unsigned int case BTRFS_IOC_ADD_DEV: return btrfs_ioctl_add_dev(root, argp); case BTRFS_IOC_RM_DEV: - return btrfs_ioctl_rm_dev(root, argp); + return btrfs_ioctl_rm_dev(file, argp); case BTRFS_IOC_FS_INFO: return btrfs_ioctl_fs_info(root, argp); case BTRFS_IOC_DEV_INFO: |