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authorMing Lei <ming.lei@redhat.com>2022-01-26 11:58:30 +0800
committerJens Axboe <axboe@kernel.dk>2022-02-11 15:10:49 -0700
commit06582bc86d7f48d35cd044098ca1e246e8c7c52e (patch)
treed6038c855d863a83b254063fd3f6bea8887a1bad /drivers/block/loop.c
parenta12821d5e012a42673f6fe521971f193441d8aa4 (diff)
block: loop:use kstatfs.f_bsize of backing file to set discard granularity
If backing file's filesystem has implemented ->fallocate(), we think the loop device can support discard, then pass sb->s_blocksize as discard_granularity. However, some underlying FS, such as overlayfs, doesn't set sb->s_blocksize, and causes discard_granularity to be set as zero, then the warning in __blkdev_issue_discard() is triggered. Christoph suggested to pass kstatfs.f_bsize as discard granularity, and this way is fine because kstatfs.f_bsize means 'Optimal transfer block size', which still matches with definition of discard granularity. So fix the issue by setting discard_granularity as kstatfs.f_bsize if it is available, otherwise claims discard isn't supported. Cc: Christoph Hellwig <hch@lst.de> Cc: Vivek Goyal <vgoyal@redhat.com> Reported-by: Pei Zhang <pezhang@redhat.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20220126035830.296465-1-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'drivers/block/loop.c')
-rw-r--r--drivers/block/loop.c8
1 files changed, 7 insertions, 1 deletions
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 150012ffb387..19fe19eaa50e 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -79,6 +79,7 @@
#include <linux/ioprio.h>
#include <linux/blk-cgroup.h>
#include <linux/sched/mm.h>
+#include <linux/statfs.h>
#include "loop.h"
@@ -774,8 +775,13 @@ static void loop_config_discard(struct loop_device *lo)
granularity = 0;
} else {
+ struct kstatfs sbuf;
+
max_discard_sectors = UINT_MAX >> 9;
- granularity = inode->i_sb->s_blocksize;
+ if (!vfs_statfs(&file->f_path, &sbuf))
+ granularity = sbuf.f_bsize;
+ else
+ max_discard_sectors = 0;
}
if (max_discard_sectors) {