From 4143179218960a70d821a425e3c23ce44aa93dee Mon Sep 17 00:00:00 2001 From: Lukas Czerner Date: Wed, 23 Feb 2011 12:42:32 -0500 Subject: [PATCH] ext4: check if device support discard in FITRIM ioctl For a device that does not support discard, the FITRIM ioctl returns -EOPNOTSUPP when blkdev_issue_discard() returns this error code, which is how the user is informed that the device does not support discard. If there are no suitable free extents to be trimmed, then FITRIM will return success even though the device does not support discard, which could confuse the user. So check explicitly if the device supports discard and return an error code at the beginning of the FITRIM ioctl processing. Signed-off-by: Lukas Czerner Signed-off-by: "Theodore Ts'o" --- fs/ext4/ioctl.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c index eb3bc2fe647e..25ba7c79d289 100644 --- a/fs/ext4/ioctl.c +++ b/fs/ext4/ioctl.c @@ -334,12 +334,16 @@ mext_out: case FITRIM: { struct super_block *sb = inode->i_sb; + struct request_queue *q = bdev_get_queue(sb->s_bdev); struct fstrim_range range; int ret = 0; if (!capable(CAP_SYS_ADMIN)) return -EPERM; + if (!blk_queue_discard(q)) + return -EOPNOTSUPP; + if (copy_from_user(&range, (struct fstrim_range *)arg, sizeof(range))) return -EFAULT;