From: Zhang Yi <yi.zhang@huawei.com>
Increase i_size in iomap_zero_range() and iomap_unshare_iter() is not
needed, the caller should handle it. Especially, when truncate partial
block, we should not increase i_size beyond the new EOF here. It doesn't
affect xfs and gfs2 now because they set the new file size after zero
out, it doesn't matter that a transient increase in i_size, but it will
affect ext4 because it set file size before truncate. So move the i_size
updating logic to iomap_write_iter().
Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
---
fs/iomap/buffered-io.c | 50 +++++++++++++++++++++---------------------
1 file changed, 25 insertions(+), 25 deletions(-)
diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index 7e32a204650b..e9112dc78d15 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -837,32 +837,13 @@ static size_t iomap_write_end(struct iomap_iter *iter, loff_t pos, size_t len,
size_t copied, struct folio *folio)
{
const struct iomap *srcmap = iomap_iter_srcmap(iter);
- loff_t old_size = iter->inode->i_size;
- size_t ret;
-
- if (srcmap->type == IOMAP_INLINE) {
- ret = iomap_write_end_inline(iter, folio, pos, copied);
- } else if (srcmap->flags & IOMAP_F_BUFFER_HEAD) {
- ret = block_write_end(NULL, iter->inode->i_mapping, pos, len,
- copied, &folio->page, NULL);
- } else {
- ret = __iomap_write_end(iter->inode, pos, len, copied, folio);
- }
-
- /*
- * Update the in-memory inode size after copying the data into the page
- * cache. It's up to the file system to write the updated size to disk,
- * preferably after I/O completion so that no stale data is exposed.
- */
- if (pos + ret > old_size) {
- i_size_write(iter->inode, pos + ret);
- iter->iomap.flags |= IOMAP_F_SIZE_CHANGED;
- }
- __iomap_put_folio(iter, pos, ret, folio);
- if (old_size < pos)
- pagecache_isize_extended(iter->inode, old_size, pos);
- return ret;
+ if (srcmap->type == IOMAP_INLINE)
+ return iomap_write_end_inline(iter, folio, pos, copied);
+ if (srcmap->flags & IOMAP_F_BUFFER_HEAD)
+ return block_write_end(NULL, iter->inode->i_mapping, pos, len,
+ copied, &folio->page, NULL);
+ return __iomap_write_end(iter->inode, pos, len, copied, folio);
}
static loff_t iomap_write_iter(struct iomap_iter *iter, struct iov_iter *i)
@@ -877,6 +858,7 @@ static loff_t iomap_write_iter(struct iomap_iter *iter, struct iov_iter *i)
do {
struct folio *folio;
+ loff_t old_size;
size_t offset; /* Offset into folio */
size_t bytes; /* Bytes to write to folio */
size_t copied; /* Bytes copied from user */
@@ -926,6 +908,22 @@ static loff_t iomap_write_iter(struct iomap_iter *iter, struct iov_iter *i)
copied = copy_folio_from_iter_atomic(folio, offset, bytes, i);
status = iomap_write_end(iter, pos, bytes, copied, folio);
+ /*
+ * Update the in-memory inode size after copying the data into
+ * the page cache. It's up to the file system to write the
+ * updated size to disk, preferably after I/O completion so that
+ * no stale data is exposed. Only once that's done can we
+ * unlock and release the folio.
+ */
+ old_size = iter->inode->i_size;
+ if (pos + status > old_size) {
+ i_size_write(iter->inode, pos + status);
+ iter->iomap.flags |= IOMAP_F_SIZE_CHANGED;
+ }
+ __iomap_put_folio(iter, pos, status, folio);
+
+ if (old_size < pos)
+ pagecache_isize_extended(iter->inode, old_size, pos);
if (status < bytes)
iomap_write_failed(iter->inode, pos + status,
bytes - status);
@@ -1298,6 +1296,7 @@ static loff_t iomap_unshare_iter(struct iomap_iter *iter)
bytes = folio_size(folio) - offset;
bytes = iomap_write_end(iter, pos, bytes, bytes, folio);
+ __iomap_put_folio(iter, pos, bytes, folio);
if (WARN_ON_ONCE(bytes == 0))
return -EIO;
@@ -1362,6 +1361,7 @@ static loff_t iomap_zero_iter(struct iomap_iter *iter, bool *did_zero)
folio_mark_accessed(folio);
bytes = iomap_write_end(iter, pos, bytes, bytes, folio);
+ __iomap_put_folio(iter, pos, bytes, folio);
if (WARN_ON_ONCE(bytes == 0))
return -EIO;
--
2.39.2On Wed, Mar 20, 2024 at 07:05:45 PM +0800, Zhang Yi wrote: > From: Zhang Yi <yi.zhang@huawei.com> > > Increase i_size in iomap_zero_range() and iomap_unshare_iter() is not > needed, the caller should handle it. Especially, when truncate partial > block, we should not increase i_size beyond the new EOF here. It doesn't > affect xfs and gfs2 now because they set the new file size after zero > out, it doesn't matter that a transient increase in i_size, but it will > affect ext4 because it set file size before truncate. So move the i_size > updating logic to iomap_write_iter(). > This patch causes generic/522 to consistently fail when using the following fstest configuration, TEST_DEV=/dev/loop16 TEST_LOGDEV=/dev/loop13 SCRATCH_DEV_POOL="/dev/loop5 /dev/loop6 /dev/loop7 /dev/loop8 /dev/loop9 /dev/loop10 /dev/loop11 /dev/loop12" MKFS_OPTIONS='-f -m reflink=1,rmapbt=1, -i sparse=1, -lsize=1g' MOUNT_OPTIONS='-o usrquota,grpquota,prjquota' TEST_FS_MOUNT_OPTS="$TEST_FS_MOUNT_OPTS -o usrquota,grpquota,prjquota" TEST_FS_MOUNT_OPTS="-o logdev=/dev/loop13" SCRATCH_LOGDEV=/dev/loop15 USE_EXTERNAL=yes LOGWRITES_DEV=/dev/loop15 -- Chandan
On 2024/4/19 14:07, Chandan Babu R wrote: > On Wed, Mar 20, 2024 at 07:05:45 PM +0800, Zhang Yi wrote: >> From: Zhang Yi <yi.zhang@huawei.com> >> >> Increase i_size in iomap_zero_range() and iomap_unshare_iter() is not >> needed, the caller should handle it. Especially, when truncate partial >> block, we should not increase i_size beyond the new EOF here. It doesn't >> affect xfs and gfs2 now because they set the new file size after zero >> out, it doesn't matter that a transient increase in i_size, but it will >> affect ext4 because it set file size before truncate. So move the i_size >> updating logic to iomap_write_iter(). >> > > This patch causes generic/522 to consistently fail when using the following > fstest configuration, > > TEST_DEV=/dev/loop16 > TEST_LOGDEV=/dev/loop13 > SCRATCH_DEV_POOL="/dev/loop5 /dev/loop6 /dev/loop7 /dev/loop8 /dev/loop9 /dev/loop10 /dev/loop11 /dev/loop12" > MKFS_OPTIONS='-f -m reflink=1,rmapbt=1, -i sparse=1, -lsize=1g' > MOUNT_OPTIONS='-o usrquota,grpquota,prjquota' > TEST_FS_MOUNT_OPTS="$TEST_FS_MOUNT_OPTS -o usrquota,grpquota,prjquota" > TEST_FS_MOUNT_OPTS="-o logdev=/dev/loop13" > SCRATCH_LOGDEV=/dev/loop15 > USE_EXTERNAL=yes > LOGWRITES_DEV=/dev/loop15 > Hello! The root cause of the problem is caused by patch 4/9, this patch is fine, I've revised the patch 4/9 and send it out separately in reply to v4. I've tested that on my machine for over 100 rounds on generic/522 and it hasn't failed again. Please take a look at the v5 patch for details and test it on your machine. https://lore.kernel.org/linux-xfs/20240423111735.1298851-1-yi.zhang@huaweicloud.com/T/#m2da33e643b642071aa20077321e2c431f5a64e38 Thanks, Yi.
On 2024/4/19 14:07, Chandan Babu R wrote: > On Wed, Mar 20, 2024 at 07:05:45 PM +0800, Zhang Yi wrote: >> From: Zhang Yi <yi.zhang@huawei.com> >> >> Increase i_size in iomap_zero_range() and iomap_unshare_iter() is not >> needed, the caller should handle it. Especially, when truncate partial >> block, we should not increase i_size beyond the new EOF here. It doesn't >> affect xfs and gfs2 now because they set the new file size after zero >> out, it doesn't matter that a transient increase in i_size, but it will >> affect ext4 because it set file size before truncate. So move the i_size >> updating logic to iomap_write_iter(). >> > > This patch causes generic/522 to consistently fail when using the following > fstest configuration, > > TEST_DEV=/dev/loop16 > TEST_LOGDEV=/dev/loop13 > SCRATCH_DEV_POOL="/dev/loop5 /dev/loop6 /dev/loop7 /dev/loop8 /dev/loop9 /dev/loop10 /dev/loop11 /dev/loop12" > MKFS_OPTIONS='-f -m reflink=1,rmapbt=1, -i sparse=1, -lsize=1g' > MOUNT_OPTIONS='-o usrquota,grpquota,prjquota' > TEST_FS_MOUNT_OPTS="$TEST_FS_MOUNT_OPTS -o usrquota,grpquota,prjquota" > TEST_FS_MOUNT_OPTS="-o logdev=/dev/loop13" > SCRATCH_LOGDEV=/dev/loop15 > USE_EXTERNAL=yes > LOGWRITES_DEV=/dev/loop15 > Sorry for the regression, I didn't notice this issue last time I ran this test. It looks like the 004 patch doesn't work for some cases. I can reproduce it on my machine now, and I'll take a look at this and fix it soon. Thanks, Yi.
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