[PATCH 6.13] btrfs: ioctl: error on fixed buffer flag for io-uring cmd

[Sidong Yang]

Currently, the io-uring fixed buffer cmd flag is silently dismissed,
even though it does not work. This patch returns an error when the flag
is set, making it clear that operation is not supported.

Fixes: 34310c442e17 ("btrfs: add io_uring command for encoded reads (ENCODED_READ ioctl)")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Sidong Yang <sidong.yang@xxxxxxxxxx>
---
 fs/btrfs/ioctl.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 4d9305fa37a8..98d99f2f7926 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -4906,6 +4906,12 @@ static int btrfs_uring_encoded_read(struct io_uring_cmd *cmd, unsigned int issue
 		ret = -EPERM;
 		goto out_acct;
 	}
+
+	if (cmd->flags & IORING_URING_CMD_FIXED) {
+		ret = -EOPNOTSUPP;
+		goto out_acct;
+	}
+
 	file = cmd->file;
 	inode = BTRFS_I(file->f_inode);
 	fs_info = inode->root->fs_info;
-- 
2.43.0