The patch titled
     Subject: zram: revalidate disk after capacity change
has been added to the -mm tree.  Its filename is
     zram-revalidate-disk-after-capacity-change.patch

This patch should soon appear at
    
http://ozlabs.org/~akpm/mmots/broken-out/zram-revalidate-disk-after-capacity-change.patch
and later at
    
http://ozlabs.org/~akpm/mmotm/broken-out/zram-revalidate-disk-after-capacity-change.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: Minchan Kim <[email protected]>
Subject: 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 <[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]>
Cc; Jerome Marchand <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
---

 drivers/block/zram/zram_drv.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff -puN 
drivers/block/zram/zram_drv.c~zram-revalidate-disk-after-capacity-change 
drivers/block/zram/zram_drv.c
--- a/drivers/block/zram/zram_drv.c~zram-revalidate-disk-after-capacity-change
+++ a/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 -mm which might be from [email protected] are

origin.patch
zram-revalidate-disk-after-capacity-change.patch
dma-cma-separate-core-cma-management-codes-from-dma-apis.patch
dma-cma-support-alignment-constraint-on-cma-region.patch
dma-cma-support-arbitrary-bitmap-granularity.patch
dma-cma-support-arbitrary-bitmap-granularity-fix.patch
cma-generalize-cma-reserved-area-management-functionality.patch
ppc-kvm-cma-use-general-cma-reserved-area-management-framework.patch
mm-cma-clean-up-cma-allocation-error-path.patch
mm-cma-change-cma_declare_contiguous-to-obey-coding-convention.patch
mm-cma-clean-up-log-message.patch
mm-vmscan-remove-remains-of-kswapd-managed-zone-all_unreclaimable.patch
mm-vmscan-rework-compaction-ready-signaling-in-direct-reclaim.patch
mm-vmscan-remove-all_unreclaimable.patch
mm-vmscan-move-swappiness-out-of-scan_control.patch
mm-compactionc-isolate_freepages_block-small-tuneup.patch
zram-rename-struct-table-to-zram_table_entry.patch
zram-remove-unused-sector_size-define.patch
mm-zbud-zbud_alloc-minor-param-change.patch
mm-zbud-change-zbud_alloc-size-type-to-size_t.patch
mm-zpool-implement-common-zpool-api-to-zbud-zsmalloc.patch
mm-zpool-zbud-zsmalloc-implement-zpool.patch
mm-zpool-update-zswap-to-use-zpool.patch
mm-zpool-prevent-zbud-zsmalloc-from-unloading-when-used.patch
debugging-keep-track-of-page-owners.patch
page-owners-correct-page-order-when-to-free-page.patch

--
To unsubscribe from this list: send the line "unsubscribe stable" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Reply via email to