Commit 41431792 authored Feb 23, 2011 by Lukas Czerner Committed by Theodore Ts'o Feb 23, 2011

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 <lczerner@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

parent 0b75a840

fs/ext4/ioctl.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -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;

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