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Message-Id: <20240529095206.2568162-7-yi.zhang@huaweicloud.com>
Date: Wed, 29 May 2024 17:52:04 +0800
From: Zhang Yi <yi.zhang@...weicloud.com>
To: linux-xfs@...r.kernel.org,
linux-fsdevel@...r.kernel.org
Cc: linux-kernel@...r.kernel.org,
djwong@...nel.org,
hch@...radead.org,
brauner@...nel.org,
david@...morbit.com,
chandanbabu@...nel.org,
jack@...e.cz,
willy@...radead.org,
yi.zhang@...wei.com,
yi.zhang@...weicloud.com,
chengzhihao1@...wei.com,
yukuai3@...wei.com
Subject: [RFC PATCH v4 6/8] xfs: correct the truncate blocksize of realtime inode
From: Zhang Yi <yi.zhang@...wei.com>
When unaligned truncating down a realtime file which sb_rextsize is
bigger than one block, xfs_truncate_page() only zeros out the tail EOF
block, this could expose stale data since commit '943bc0882ceb ("iomap:
don't increase i_size if it's not a write operation")'.
If we truncate file that contains a large enough written extent:
|< rxext >|< rtext >|
...WWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWW
^ (new EOF) ^ old EOF
Since we only zeros out the tail of the EOF block, and
xfs_itruncate_extents() unmap the whole ailgned extents, it becomes
this state:
|< rxext >|
...WWWzWWWWWWWWWWWWW
^ new EOF
Then if we do an extending write like this, the blocks in the previous
tail extent becomes stale:
|< rxext >|
...WWWzSSSSSSSSSSSSS..........WWWWWWWWWWWWWWWWW
^ old EOF ^ append start ^ new EOF
Fix this by zeroing out the tail allocation uint and also make sure
xfs_itruncate_extents() unmap rtextsize aligned extents.
Fixes: 943bc0882ceb ("iomap: don't increase i_size if it's not a write operation")
Reported-by: Chandan Babu R <chandanbabu@...nel.org>
Link: https://lore.kernel.org/linux-xfs/0b92a215-9d9b-3788-4504-a520778953c2@huaweicloud.com
Signed-off-by: Zhang Yi <yi.zhang@...wei.com>
---
fs/xfs/xfs_inode.c | 3 +++
fs/xfs/xfs_iops.c | 2 +-
2 files changed, 4 insertions(+), 1 deletion(-)
diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index 58fb7a5062e1..db35167acef6 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -35,6 +35,7 @@
#include "xfs_trans_priv.h"
#include "xfs_log.h"
#include "xfs_bmap_btree.h"
+#include "xfs_rtbitmap.h"
#include "xfs_reflink.h"
#include "xfs_ag.h"
#include "xfs_log_priv.h"
@@ -1512,6 +1513,8 @@ xfs_itruncate_extents_flags(
* the page cache can't scale that far.
*/
first_unmap_block = XFS_B_TO_FSB(mp, (xfs_ufsize_t)new_size);
+ if (xfs_inode_has_bigrtalloc(ip))
+ first_unmap_block = xfs_rtb_roundup_rtx(mp, first_unmap_block);
if (!xfs_verify_fileoff(mp, first_unmap_block)) {
WARN_ON_ONCE(first_unmap_block > XFS_MAX_FILEOFF);
return 0;
diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
index d24927075022..ec7b7bdf8825 100644
--- a/fs/xfs/xfs_iops.c
+++ b/fs/xfs/xfs_iops.c
@@ -865,7 +865,7 @@ xfs_setattr_size(
*/
write_back = newsize > ip->i_disk_size && oldsize != ip->i_disk_size;
if (newsize < oldsize) {
- unsigned int blocksize = i_blocksize(inode);
+ unsigned int blocksize = xfs_inode_alloc_unitsize(ip);
/*
* Zeroing out the partial EOF block and the rest of the extra
--
2.39.2
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