* [PATCH] btrfs: protect sb_write_pointer() with invalidate lock
@ 2026-05-21 12:29 KangNing Liao
2026-05-21 22:14 ` Qu Wenruo
0 siblings, 1 reply; 2+ messages in thread
From: KangNing Liao @ 2026-05-21 12:29 UTC (permalink / raw)
To: linux-btrfs; +Cc: clm, dsterba, eadavis, linux-kernel
sb_write_pointer() reads the super block from the block device page cache
using read_cache_page_gfp(). This has the same race with BLKBSZSET as the
one fixed by commit 3f29d661e568 ("btrfs: sync read disk super and set
block size").
Take the mapping invalidate lock around read_cache_page_gfp() to
serialize the read against block size changes.
Signed-off-by: KangNing Liao <lkangn.kernel@gmail.com>
---
fs/btrfs/zoned.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c
index 16dd87aa06f2..5f75cf0e14b9 100644
--- a/fs/btrfs/zoned.c
+++ b/fs/btrfs/zoned.c
@@ -131,8 +131,10 @@ static int sb_write_pointer(struct block_device *bdev, struct blk_zone *zones,
u64 bytenr = ALIGN_DOWN(zone_end, BTRFS_SUPER_INFO_SIZE) -
BTRFS_SUPER_INFO_SIZE;
+ filemap_invalidate_lock(mapping);
page[i] = read_cache_page_gfp(mapping,
bytenr >> PAGE_SHIFT, GFP_NOFS);
+ filemap_invalidate_unlock(mapping);
if (IS_ERR(page[i])) {
if (i == 1)
btrfs_release_disk_super(super[0]);
--
2.54.0
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] btrfs: protect sb_write_pointer() with invalidate lock
2026-05-21 12:29 [PATCH] btrfs: protect sb_write_pointer() with invalidate lock KangNing Liao
@ 2026-05-21 22:14 ` Qu Wenruo
0 siblings, 0 replies; 2+ messages in thread
From: Qu Wenruo @ 2026-05-21 22:14 UTC (permalink / raw)
To: KangNing Liao, linux-btrfs; +Cc: clm, dsterba, eadavis, linux-kernel
在 2026/5/21 21:59, KangNing Liao 写道:
> sb_write_pointer() reads the super block from the block device page cache
> using read_cache_page_gfp(). This has the same race with BLKBSZSET as the
> one fixed by commit 3f29d661e568 ("btrfs: sync read disk super and set
> block size").
>
> Take the mapping invalidate lock around read_cache_page_gfp() to
> serialize the read against block size changes.
>
> Signed-off-by: KangNing Liao <lkangn.kernel@gmail.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Thanks,
Qu
> ---
> fs/btrfs/zoned.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c
> index 16dd87aa06f2..5f75cf0e14b9 100644
> --- a/fs/btrfs/zoned.c
> +++ b/fs/btrfs/zoned.c
> @@ -131,8 +131,10 @@ static int sb_write_pointer(struct block_device *bdev, struct blk_zone *zones,
> u64 bytenr = ALIGN_DOWN(zone_end, BTRFS_SUPER_INFO_SIZE) -
> BTRFS_SUPER_INFO_SIZE;
>
> + filemap_invalidate_lock(mapping);
> page[i] = read_cache_page_gfp(mapping,
> bytenr >> PAGE_SHIFT, GFP_NOFS);
> + filemap_invalidate_unlock(mapping);
> if (IS_ERR(page[i])) {
> if (i == 1)
> btrfs_release_disk_super(super[0]);
^ permalink raw reply [flat|nested] 2+ messages in thread
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2026-05-21 22:14 ` Qu Wenruo
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