The patch titled
Subject: iomap: use filemap_range_needs_writeback() for O_DIRECT reads
has been added to the -mm tree. Its filename is
iomap-use-filemap_range_needs_writeback-for-o_direct-reads.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/iomap-use-filemap_range_needs_writeback-for-o_direct-reads.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/iomap-use-filemap_range_needs_writeback-for-o_direct-reads.patch
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------------------------------------------------------
From: Jens Axboe <axboe@xxxxxxxxx>
Subject: iomap: use filemap_range_needs_writeback() for O_DIRECT reads
For reads, use the better variant of checking for the need to call
filemap_write_and_wait_range() when doing O_DIRECT. This avoids falling
back to the slow path for IOCB_NOWAIT, if there are no pages to wait for
(or write out).
Link: https://lkml.kernel.org/r/20210224164455.1096727-4-axboe@xxxxxxxxx
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Reviewed-by: Jan Kara <jack@xxxxxxx>
Cc: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/iomap/direct-io.c | 24 ++++++++++++++++--------
1 file changed, 16 insertions(+), 8 deletions(-)
--- a/fs/iomap/direct-io.c~iomap-use-filemap_range_needs_writeback-for-o_direct-reads
+++ a/fs/iomap/direct-io.c
@@ -487,12 +487,28 @@ __iomap_dio_rw(struct kiocb *iocb, struc
if (pos >= dio->i_size)
goto out_free_dio;
+ if (iocb->ki_flags & IOCB_NOWAIT) {
+ if (filemap_range_needs_writeback(mapping, pos, end)) {
+ ret = -EAGAIN;
+ goto out_free_dio;
+ }
+ iomap_flags |= IOMAP_NOWAIT;
+ }
+
if (iter_is_iovec(iter))
dio->flags |= IOMAP_DIO_DIRTY;
} else {
iomap_flags |= IOMAP_WRITE;
dio->flags |= IOMAP_DIO_WRITE;
+ if (iocb->ki_flags & IOCB_NOWAIT) {
+ if (filemap_range_has_page(mapping, pos, end)) {
+ ret = -EAGAIN;
+ goto out_free_dio;
+ }
+ iomap_flags |= IOMAP_NOWAIT;
+ }
+
/* for data sync or sync, we need sync completion processing */
if (iocb->ki_flags & IOCB_DSYNC)
dio->flags |= IOMAP_DIO_NEED_SYNC;
@@ -507,14 +523,6 @@ __iomap_dio_rw(struct kiocb *iocb, struc
dio->flags |= IOMAP_DIO_WRITE_FUA;
}
- if (iocb->ki_flags & IOCB_NOWAIT) {
- if (filemap_range_has_page(mapping, pos, end)) {
- ret = -EAGAIN;
- goto out_free_dio;
- }
- iomap_flags |= IOMAP_NOWAIT;
- }
-
if (dio_flags & IOMAP_DIO_OVERWRITE_ONLY) {
ret = -EAGAIN;
if (pos >= dio->i_size || pos + count > dio->i_size)
_
Patches currently in -mm which might be from axboe@xxxxxxxxx are
swap-fix-swapfile-read-write-offset.patch
mm-provide-filemap_range_needs_writeback-helper.patch
mm-use-filemap_range_needs_writeback-for-o_direct-reads.patch
iomap-use-filemap_range_needs_writeback-for-o_direct-reads.patch
