From: David Sterba <dsterba@xxxxxxx>
commit 7ab19625a911f7568ec85302e3aa7a64186006c8 upstream.
Perform the want_write check if we get far enough to do any writes.
Signed-off-by: David Sterba <dsterba@xxxxxxxx>
---
fs/btrfs/ioctl.c | 16 +++++++++++++---
1 file changed, 13 insertions(+), 3 deletions(-)
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index ea21e588a839..14e291422ab1 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -5397,9 +5397,15 @@ static int btrfs_ioctl_set_features(struct file *file, void __user *arg)
if (ret)
return ret;
+ ret = mnt_want_write_file(file);
+ if (ret)
+ return ret;
+
trans = btrfs_start_transaction(root, 0);
- if (IS_ERR(trans))
- return PTR_ERR(trans);
+ if (IS_ERR(trans)) {
+ ret = PTR_ERR(trans);
+ goto out_drop_write;
+ }
spin_lock(&root->fs_info->super_lock);
newflags = btrfs_super_compat_flags(super_block);
@@ -5418,7 +5424,11 @@ static int btrfs_ioctl_set_features(struct file *file, void __user *arg)
btrfs_set_super_incompat_flags(super_block, newflags);
spin_unlock(&root->fs_info->super_lock);
- return btrfs_commit_transaction(trans, root);
+ ret = btrfs_commit_transaction(trans, root);
+out_drop_write:
+ mnt_drop_write_file(file);
+
+ return ret;
}
long btrfs_ioctl(struct file *file, unsigned int
--
2.7.1
--
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