This is a note to let you know that I've just added the patch titled
zram: revalidate disk after capacity change
to the 3.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
zram-revalidate-disk-after-capacity-change.patch
and it can be found in the queue-3.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From 2e32baea46ce542c561a519414c840295b229c8f Mon Sep 17 00:00:00 2001
From: Minchan Kim <[email protected]>
Date: Wed, 2 Jul 2014 15:22:36 -0700
Subject: zram: revalidate disk after capacity change
From: Minchan Kim <[email protected]>
commit 2e32baea46ce542c561a519414c840295b229c8f upstream.
Alexander reported mkswap on /dev/zram0 is failed if other process is
opening the block device file.
Step is as follows,
0. Reset the unused zram device.
1. Use a program that opens /dev/zram0 with O_RDWR and sleeps
until killed.
2. While that program sleeps, echo the correct value to
/sys/block/zram0/disksize.
3. Verify (e.g. in /proc/partitions) that the disk size is applied
correctly. It is.
4. While that program still sleeps, attempt to mkswap /dev/zram0.
This fails: mkswap: error: swap area needs to be at least 40 KiB
When I investigated, the size get by ioctl(fd, BLKGETSIZE64, xxx) on
mkswap to get a size of blockdev was zero although zram0 has right size by
2.
The reason is zram didn't revalidate disk after changing capacity so that
size of blockdev's inode is not uptodate until all of file is close.
This patch should fix the BUG.
Signed-off-by: Minchan Kim <[email protected]>
Reported-by: Alexander E. Patrakov <[email protected]>
Tested-by: Alexander E. Patrakov <[email protected]>
Reviewed-by: Sergey Senozhatsky <[email protected]>
Cc: Nitin Gupta <[email protected]>
Acked-by: Jerome Marchand <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
drivers/block/zram/zram_drv.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -622,8 +622,10 @@ static void zram_reset_device(struct zra
memset(&zram->stats, 0, sizeof(zram->stats));
zram->disksize = 0;
- if (reset_capacity)
+ if (reset_capacity) {
set_capacity(zram->disk, 0);
+ revalidate_disk(zram->disk);
+ }
up_write(&zram->init_lock);
}
@@ -664,6 +666,7 @@ static ssize_t disksize_store(struct dev
zram->comp = comp;
zram->disksize = disksize;
set_capacity(zram->disk, zram->disksize >> SECTOR_SHIFT);
+ revalidate_disk(zram->disk);
up_write(&zram->init_lock);
return len;
Patches currently in stable-queue which might be from [email protected] are
queue-3.15/zram-revalidate-disk-after-capacity-change.patch
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