Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
mpage: Provide variant of mpage_writepages() with own optional folio handler
Some filesystems need to treat some folios specially (for example for
inodes with inline data). Doing the handling in their .writepages method
in a race-free manner results in duplicating some of the writeback
internals. So provide generalized version of mpage_writepages() that
allows filesystem to provide a handler called for each folio which can
handle the folio in a special way.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://patch.msgid.link/20260326140635.15895-3-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
+33
-8
+24
-6
fs/mpage.c
+24
-6
fs/mpage.c
···
646
646
}
647
647
648
648
/**
649
-
* mpage_writepages - walk the list of dirty pages of the given address space & writepage() all of them
649
+
* __mpage_writepages - walk the list of dirty pages of the given address space
650
+
* & writepage() all of them
650
651
* @mapping: address space structure to write
651
652
* @wbc: subtract the number of written pages from *@wbc->nr_to_write
652
653
* @get_block: the filesystem's block mapper function.
654
+
* @write_folio: handler to call for each folio before calling
655
+
* mpage_write_folio()
653
656
*
654
657
* This is a library function, which implements the writepages()
655
-
* address_space_operation.
658
+
* address_space_operation. It calls @write_folio handler for each folio. If
659
+
* the handler returns value > 0, it calls mpage_write_folio() to do the
660
+
* folio writeback.
656
661
*/
657
662
int
658
-
mpage_writepages(struct address_space *mapping,
659
-
struct writeback_control *wbc, get_block_t get_block)
663
+
__mpage_writepages(struct address_space *mapping,
664
+
struct writeback_control *wbc, get_block_t get_block,
665
+
int (*write_folio)(struct folio *folio,
666
+
struct writeback_control *wbc))
660
667
{
661
668
struct mpage_data mpd = {
662
669
.get_block = get_block,
···
673
666
int error;
674
667
675
668
blk_start_plug(&plug);
676
-
while ((folio = writeback_iter(mapping, wbc, folio, &error)))
669
+
while ((folio = writeback_iter(mapping, wbc, folio, &error))) {
670
+
if (write_folio) {
671
+
error = write_folio(folio, wbc);
672
+
/*
673
+
* == 0 means folio is handled, < 0 means error. In
674
+
* both cases hand back control to writeback_iter()
675
+
*/
676
+
if (error <= 0)
677
+
continue;
678
+
/* Let mpage_write_folio() handle the folio. */
679
+
}
677
680
error = mpage_write_folio(wbc, folio, &mpd);
681
+
}
678
682
if (mpd.bio)
679
683
mpage_bio_submit_write(mpd.bio);
680
684
blk_finish_plug(&plug);
681
685
return error;
682
686
}
683
-
EXPORT_SYMBOL(mpage_writepages);
687
+
EXPORT_SYMBOL(__mpage_writepages);
+9
-2
include/linux/mpage.h
+9
-2
include/linux/mpage.h
···
17
17
18
18
void mpage_readahead(struct readahead_control *, get_block_t get_block);
19
19
int mpage_read_folio(struct folio *folio, get_block_t get_block);
20
-
int mpage_writepages(struct address_space *mapping,
21
-
struct writeback_control *wbc, get_block_t get_block);
20
+
int __mpage_writepages(struct address_space *mapping,
21
+
struct writeback_control *wbc, get_block_t get_block,
22
+
int (*write_folio)(struct folio *folio,
23
+
struct writeback_control *wbc));
24
+
static inline int mpage_writepages(struct address_space *mapping,
25
+
struct writeback_control *wbc, get_block_t get_block)
26
+
{
27
+
return __mpage_writepages(mapping, wbc, get_block, NULL);
28
+
}
22
29
23
30
#endif