The patch titled
Subject: loopdev: ignore negative offset when calculate loop device size
has been added to the -mm tree. Its filename is
loopdev-ignore-negative-offset-when-calculate-loop-device-size.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/SubmitChecklist when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Guo Chao <yan@xxxxxxxxxxxxxxxxxx>
Subject: loopdev: ignore negative offset when calculate loop device size
Negative offset may cause loop device size larger than backing file
size.
$ fallocate -l 1M a
$ losetup --offset 0xffffffffffff0000 /dev/loop0 a
$ blockdev --getsize64 /dev/loop0
1114112
$ ls -l a
-rw-r--r-- 1 root root 1048576 Jan 23 12:46 a
$ cat /dev/loop0
cat: /dev/loop0: Input/output error
It makes no sense to do that. Only apply offset when it's positive.
Fix a typo in the comment by the way.
Signed-off-by: Guo Chao <yan@xxxxxxxxxxxxxxxxxx>
Cc: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Guo Chao <yan@xxxxxxxxxxxxxxxxxx>
Cc: M. Hindess <hindessm@xxxxxxxxxx>
Cc: Nikanth Karthikesan <knikanth@xxxxxxx>
Cc: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/block/loop.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
diff -puN drivers/block/loop.c~loopdev-ignore-negative-offset-when-calculate-loop-device-size drivers/block/loop.c
--- a/drivers/block/loop.c~loopdev-ignore-negative-offset-when-calculate-loop-device-size
+++ a/drivers/block/loop.c
@@ -162,12 +162,13 @@ static struct loop_func_table *xfer_func
static loff_t get_size(loff_t offset, loff_t sizelimit, struct file *file)
{
- loff_t size, loopsize;
+ loff_t loopsize;
/* Compute loopsize in bytes */
- size = i_size_read(file->f_mapping->host);
- loopsize = size - offset;
- /* offset is beyond i_size, wierd but possible */
+ loopsize = i_size_read(file->f_mapping->host);
+ if (offset > 0)
+ loopsize -= offset;
+ /* offset is beyond i_size, weird but possible */
if (loopsize < 0)
return 0;
_
Patches currently in -mm which might be from yan@xxxxxxxxxxxxxxxxxx are
linux-next.patch
block-use-i_size_write-in-bd_set_size.patch
block-remove-redundant-check-to-bd_openers.patch
loopdev-fix-a-deadlock.patch
loopdev-update-block-device-size-in-loop_set_status.patch
loopdev-move-common-code-into-loop_figure_size.patch
loopdev-remove-an-user-triggerable-oops.patch
loopdev-ignore-negative-offset-when-calculate-loop-device-size.patch
--
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
