diff options
| author | Miao Xie <miaox@cn.fujitsu.com> | 2012-11-26 08:43:45 +0000 |
|---|---|---|
| committer | Chris Mason <chris.mason@fusionio.com> | 2012-12-16 20:46:09 -0500 |
| commit | 198605a8e2077f174c9834c97b836f535e4e56dd (patch) | |
| tree | 1dae7f3529ead027b13ae4737f5b5cedb267d3a0 | |
| parent | 3c04ce01053413007b9df88313b8b8e17272b57b (diff) | |
Btrfs: get write access when doing resize fs
Steps to reproduce:
# mkfs.btrfs <partition>
# mount -o ro <partition> <mnt0>
# mount -o ro <partition> <mnt1>
# mount -o remount,rw <mnt0>
# umount <mnt0>
# btrfs fi resize 10g <mnt1>
We re-sized 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>
| -rw-r--r-- | fs/btrfs/ioctl.c | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index 10bc65ed736c..2be49b4c82d6 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -1298,12 +1298,13 @@ out_ra: return ret; } -static noinline int btrfs_ioctl_resize(struct btrfs_root *root, +static noinline int btrfs_ioctl_resize(struct file *file, void __user *arg) { u64 new_size; u64 old_size; u64 devid = 1; + struct btrfs_root *root = BTRFS_I(fdentry(file)->d_inode)->root; struct btrfs_ioctl_vol_args *vol_args; struct btrfs_trans_handle *trans; struct btrfs_device *device = NULL; @@ -1318,6 +1319,10 @@ static noinline int btrfs_ioctl_resize(struct btrfs_root *root, if (!capable(CAP_SYS_ADMIN)) return -EPERM; + 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"); @@ -1425,6 +1430,7 @@ out_free: 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; } @@ -3832,7 +3838,7 @@ long btrfs_ioctl(struct file *file, unsigned int case BTRFS_IOC_DEFRAG_RANGE: return btrfs_ioctl_defrag(file, argp); case BTRFS_IOC_RESIZE: - return btrfs_ioctl_resize(root, argp); + return btrfs_ioctl_resize(file, argp); case BTRFS_IOC_ADD_DEV: return btrfs_ioctl_add_dev(root, argp); case BTRFS_IOC_RM_DEV: |