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authorMinchan Kim <minchan@kernel.org>2014-07-02 15:22:36 -0700
committerAlex Shi <alex.shi@linaro.org>2015-05-11 21:03:20 +0800
commit888210267e226f437abb7fd0604530032a98cafa (patch)
tree6f27d41824c6c72432c5bd7b8fc4f9261131cb20 /drivers
parentc398e6a3df7562a1a70e2ad487dcda2c3cb635e9 (diff)
downloadlinux-linaro-stable-888210267e226f437abb7fd0604530032a98cafa.tar.gz
zram: revalidate disk after capacity change
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 <minchan@kernel.org> Reported-by: Alexander E. Patrakov <patrakov@gmail.com> Tested-by: Alexander E. Patrakov <patrakov@gmail.com> Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Nitin Gupta <ngupta@vflare.org> Acked-by: Jerome Marchand <jmarchan@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> (cherry picked from commit 2e32baea46ce542c561a519414c840295b229c8f) Signed-off-by: Alex Shi <alex.shi@linaro.org>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/block/zram/zram_drv.c5
1 files changed, 4 insertions, 1 deletions
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index efb6ff2a3735..1e14825bd02b 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -621,8 +621,10 @@ static void zram_reset_device(struct zram *zram, bool reset_capacity)
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);
}
@@ -663,6 +665,7 @@ static ssize_t disksize_store(struct device *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;