[PATCH v2 3/6] iomap: advance the ifs allocation if we have more than one blocks per folio

Zhang Yi
2024-08-12T12:16:21Z

From: Zhang Yi <yi.zhang@huawei.com>

Now we allocate ifs if i_blocks_per_folio is larger than one when
writing back dirty folios in iomap_writepage_map(), so we don't attach
an ifs after buffer write to an entire folio until it starts writing
back, if we partial truncate that folio, iomap_invalidate_folio() can't
clear counterpart block's dirty bit as expected. Fix this by advance the
ifs allocation to __iomap_write_begin().

Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
---
fs/iomap/buffered-io.c | 17 ++++++++++++-----
1 file changed, 12 insertions(+), 5 deletions(-)

diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index 763deabe8331..79031b7517e5 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -699,6 +699,12 @@ static int __iomap_write_begin(const struct iomap_iter *iter, loff_t pos,
size_t from = offset_in_folio(folio, pos), to = from + len;
size_t poff, plen;

+ if (nr_blocks > 1) {
+ ifs = ifs_alloc(iter->inode, folio, iter->flags);
+ if ((iter->flags & IOMAP_NOWAIT) && !ifs)
+ return -EAGAIN;
+ }
+
/*
* If the write or zeroing completely overlaps the current folio, then
* entire folio will be dirtied so there is no need for
@@ -710,10 +716,6 @@ static int __iomap_write_begin(const struct iomap_iter *iter, loff_t pos,
pos + len >= folio_pos(folio) + folio_size(folio))
return 0;

- ifs = ifs_alloc(iter->inode, folio, iter->flags);
- if ((iter->flags & IOMAP_NOWAIT) && !ifs && nr_blocks > 1)
- return -EAGAIN;
-
if (folio_test_uptodate(folio))
return 0;

@@ -1928,7 +1930,12 @@ static int iomap_writepage_map(struct iomap_writepage_ctx *wpc,
WARN_ON_ONCE(end_pos <= pos);

if (i_blocks_per_folio(inode, folio) > 1) {
- if (!ifs) {
+ /*
+ * This should not happen since we always allocate ifs in
+ * iomap_folio_mkwrite_iter() and there is more than one
+ * blocks per folio in __iomap_write_begin().
+ */
+ if (WARN_ON_ONCE(!ifs)) {
ifs = ifs_alloc(inode, folio, 0);
iomap_set_range_dirty(folio, 0, end_pos - pos);
}
--
2.39.2