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| author | Al Viro <viro@zeniv.linux.org.uk> | 2022-06-07 22:04:03 +0200 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2022-06-10 22:03:35 +0200 |
| commit | 36518b6b4da7e8d4387bc19ad21e772f1060e9d7 (patch) | |
| tree | b091764545f997c76f720f13914f2b171d9737e4 | |
| parent | No need of likely/unlikely on calls of check_copy_size() (diff) | |
| download | linux-36518b6b4da7e8d4387bc19ad21e772f1060e9d7.tar.xz linux-36518b6b4da7e8d4387bc19ad21e772f1060e9d7.zip | |
teach iomap_dio_rw() to suppress dsync
New flag, equivalent to removal of IOCB_DSYNC from iocb flags.
This mimics what btrfs is doing (and that's what btrfs will
switch to). However, I'm not at all sure that we want to
suppress REQ_FUA for those - all btrfs hack really cares about
is suppression of generic_write_sync(). For now let's keep
the existing behaviour, but I really want to hear more detailed
arguments pro or contra.
[folded brain fix from willy]
Suggested-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| -rw-r--r-- | fs/iomap/direct-io.c | 20 | ||||
| -rw-r--r-- | include/linux/iomap.h | 6 |
2 files changed, 17 insertions, 9 deletions
diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c index 370c3241618a..c10c69e2de24 100644 --- a/fs/iomap/direct-io.c +++ b/fs/iomap/direct-io.c @@ -548,17 +548,19 @@ __iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, } /* for data sync or sync, we need sync completion processing */ - if (iocb->ki_flags & IOCB_DSYNC) + if (iocb->ki_flags & IOCB_DSYNC && + !(dio_flags & IOMAP_DIO_NOSYNC)) { dio->flags |= IOMAP_DIO_NEED_SYNC; - /* - * For datasync only writes, we optimistically try using FUA for - * this IO. Any non-FUA write that occurs will clear this flag, - * hence we know before completion whether a cache flush is - * necessary. - */ - if ((iocb->ki_flags & (IOCB_DSYNC | IOCB_SYNC)) == IOCB_DSYNC) - dio->flags |= IOMAP_DIO_WRITE_FUA; + /* + * For datasync only writes, we optimistically try + * using FUA for this IO. Any non-FUA write that + * occurs will clear this flag, hence we know before + * completion whether a cache flush is necessary. + */ + if (!(iocb->ki_flags & IOCB_SYNC)) + dio->flags |= IOMAP_DIO_WRITE_FUA; + } } if (dio_flags & IOMAP_DIO_OVERWRITE_ONLY) { diff --git a/include/linux/iomap.h b/include/linux/iomap.h index e552097c67e0..c8622d8f064e 100644 --- a/include/linux/iomap.h +++ b/include/linux/iomap.h @@ -353,6 +353,12 @@ struct iomap_dio_ops { */ #define IOMAP_DIO_PARTIAL (1 << 2) +/* + * The caller will sync the write if needed; do not sync it within + * iomap_dio_rw. Overrides IOMAP_DIO_FORCE_WAIT. + */ +#define IOMAP_DIO_NOSYNC (1 << 3) + ssize_t iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, const struct iomap_ops *ops, const struct iomap_dio_ops *dops, unsigned int dio_flags, void *private, size_t done_before); |