[PATCH 2/7] btrfs: move user provided string checks outside of volume_mutex

[Anand Jain]

Do string check for the device's new size before volume_mutex is held.

Signed-off-by: Anand Jain <anand.j...@oracle.com>
---
 fs/btrfs/ioctl.c | 37 +++++++++++++++++++------------------
 1 file changed, 19 insertions(+), 18 deletions(-)

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 2eb220213d63..b0465020972a 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -1445,7 +1445,7 @@ static noinline int btrfs_ioctl_resize(struct file *file,
 {
        struct inode *inode = file_inode(file);
        struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
-       u64 new_size;
+       u64 new_size = 0;
        u64 old_size;
        u64 devid = 1;
        struct btrfs_root *root = BTRFS_I(inode)->root;
@@ -1494,6 +1494,21 @@ static noinline int btrfs_ioctl_resize(struct file *file,
                btrfs_info(fs_info, "resizing devid %llu", devid);
        }
 
+       if (strcmp(sizestr, "max")) {
+               if (sizestr[0] == '-') {
+                       mod = -1;
+                       sizestr++;
+               } else if (sizestr[0] == '+') {
+                       mod = 1;
+                       sizestr++;
+               }
+               new_size = memparse(sizestr, &retptr);
+               if (*retptr != '\0' || new_size == 0) {
+                       ret = -EINVAL;
+                       goto out_free;
+               }
+       }
+
        mutex_lock(&fs_info->volume_mutex);
        device = btrfs_find_device(fs_info, devid, NULL, NULL);
        if (!device) {
@@ -1511,28 +1526,14 @@ static noinline int btrfs_ioctl_resize(struct file 
*file,
                goto out_mutex;
        }
 
-       if (!strcmp(sizestr, "max"))
-               new_size = device->bdev->bd_inode->i_size;
-       else {
-               if (sizestr[0] == '-') {
-                       mod = -1;
-                       sizestr++;
-               } else if (sizestr[0] == '+') {
-                       mod = 1;
-                       sizestr++;
-               }
-               new_size = memparse(sizestr, &retptr);
-               if (*retptr != '\0' || new_size == 0) {
-                       ret = -EINVAL;
-                       goto out_mutex;
-               }
-       }
-
        if (device->is_tgtdev_for_dev_replace) {
                ret = -EPERM;
                goto out_mutex;
        }
 
+       if (!new_size)
+               new_size = device->bdev->bd_inode->i_size;
+
        old_size = btrfs_device_get_total_bytes(device);
 
        if (mod < 0) {
-- 
2.13.1

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