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iomap: don't increase i_size in iomap_write_end()

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This reverts commit '0841ea4a3b41 ("iomap: keep on increasing i_size in
iomap_write_end()")'.

After xfs could zero out the tail blocks aligned to the allocation
unitsize and convert the tail blocks to unwritten for realtime inode on
truncate down, it couldn't expose any stale data when unaligned truncate
down realtime inodes, so we could keep on keeping i_size for
IOMAP_UNSHARE and IOMAP_ZERO in iomap_write_end().

Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
Link: https://lore.kernel.org/r/20240618142112.1315279-3-yi.zhang@huaweicloud.com
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
This commit is contained in:
Zhang Yi 2024-06-18 22:21:12 +08:00 committed by Christian Brauner
parent d048945150
commit 602f09f402
No known key found for this signature in database
GPG Key ID: 91C61BC06578DCA2
1 changed files with 30 additions and 25 deletions
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55
fs/iomap/buffered-io.c
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@ -896,37 +896,22 @@ static bool 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 written;
if (srcmap->type == IOMAP_INLINE) {
iomap_write_end_inline(iter, folio, pos, copied);
written = copied;
} else if (srcmap->flags & IOMAP_F_BUFFER_HEAD) {
written = block_write_end(NULL, iter->inode->i_mapping, pos,
return true;
}
if (srcmap->flags & IOMAP_F_BUFFER_HEAD) {
size_t bh_written;
bh_written = block_write_end(NULL, iter->inode->i_mapping, pos,
len, copied, &folio->page, NULL);
WARN_ON_ONCE(written != copied && written != 0);
} else {
written = __iomap_write_end(iter->inode, pos, len, copied,
folio) ? copied : 0;
WARN_ON_ONCE(bh_written != copied && bh_written != 0);
return bh_written == copied;
}
/*
* 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.
*/
if (pos + written > old_size) {
i_size_write(iter->inode, pos + written);
iter->iomap.flags |= IOMAP_F_SIZE_CHANGED;
}
__iomap_put_folio(iter, pos, written, folio);
if (old_size < pos)
pagecache_isize_extended(iter->inode, old_size, pos);
return written == copied;
return __iomap_write_end(iter->inode, pos, len, copied, folio);
}
static loff_t iomap_write_iter(struct iomap_iter *iter, struct iov_iter *i)
@ -941,6 +926,7 @@ 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 */
@ -992,6 +978,23 @@ retry:
written = iomap_write_end(iter, pos, bytes, copied, folio) ?
copied : 0;
/*
* 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 + written > old_size) {
i_size_write(iter->inode, pos + written);
iter->iomap.flags |= IOMAP_F_SIZE_CHANGED;
}
__iomap_put_folio(iter, pos, written, folio);
if (old_size < pos)
pagecache_isize_extended(iter->inode, old_size, pos);
cond_resched();
if (unlikely(written == 0)) {
/*
@ -1362,6 +1365,7 @@ static loff_t iomap_unshare_iter(struct iomap_iter *iter)
bytes = folio_size(folio) - offset;
ret = iomap_write_end(iter, pos, bytes, bytes, folio);
__iomap_put_folio(iter, pos, bytes, folio);
if (WARN_ON_ONCE(!ret))
return -EIO;
@ -1427,6 +1431,7 @@ static loff_t iomap_zero_iter(struct iomap_iter *iter, bool *did_zero)
folio_mark_accessed(folio);
ret = iomap_write_end(iter, pos, bytes, bytes, folio);
__iomap_put_folio(iter, pos, bytes, folio);
if (WARN_ON_ONCE(!ret))
return -EIO;