since linux 4.9, block device supports fallocate. kernel issues
block device zereout request and invalidates page cache. So
ioctl(fd, FALLOC_FL_ZERO_RANGE...) is safer than ioctl(fd,
BLKZEROOUT...). try to call do_fallocate, if failing, fallback.
use new field "has_fallocate_zero_range" with default value as
true. if do_fallocate returns -ENOTSUP, it will be set false.
Signed-off-by: zhenwei.pi <zhenwei.pi@youruncloud.com>
---
block/file-posix.c | 27 +++++++++++++++++----------
1 file changed, 17 insertions(+), 10 deletions(-)
diff --git a/block/file-posix.c b/block/file-posix.c
index d7fb772..842e940 100644
--- a/block/file-posix.c
+++ b/block/file-posix.c
@@ -159,8 +159,9 @@ typedef struct BDRVRawState {
bool discard_zeroes:1;
bool use_linux_aio:1;
bool page_cache_inconsistent:1;
- bool has_fallocate;
- bool needs_alignment;
+ bool has_fallocate:1;
+ bool has_fallocate_zero_range:1;
+ bool needs_alignment:1;
PRManager *pr_mgr;
} BDRVRawState;
@@ -549,6 +550,7 @@ static int raw_open_common(BlockDriverState *bs, QDict *options,
s->has_discard = true;
s->has_write_zeroes = true;
+ s->has_fallocate_zero_range = true;
if ((bs->open_flags & BDRV_O_NOCACHE) != 0) {
s->needs_alignment = true;
}
@@ -1365,10 +1367,6 @@ static ssize_t handle_aiocb_write_zeroes(RawPosixAIOData *aiocb)
int64_t len;
#endif
- if (aiocb->aio_type & QEMU_AIO_BLKDEV) {
- return handle_aiocb_write_zeroes_block(aiocb);
- }
-
#ifdef CONFIG_XFS
if (s->is_xfs) {
return xfs_write_zeroes(s, aiocb->aio_offset, aiocb->aio_nbytes);
@@ -1376,16 +1374,25 @@ static ssize_t handle_aiocb_write_zeroes(RawPosixAIOData *aiocb)
#endif
#ifdef CONFIG_FALLOCATE_ZERO_RANGE
- if (s->has_write_zeroes) {
+ /* since linux 4.9, block device supports fallocate. kernel issues
+ * block device zereout request and invalidates page cache. So
+ * ioctl(fd, FALLOC_FL_ZERO_RANGE...) is safer than ioctl(fd,
+ * BLKZEROOUT...). try to call do_fallocate, if failing, fallback.
+ */
+ if (s->has_fallocate_zero_range) {
int ret = do_fallocate(s->fd, FALLOC_FL_ZERO_RANGE,
aiocb->aio_offset, aiocb->aio_nbytes);
- if (ret == 0 || ret != -ENOTSUP) {
+ if (ret == 0) {
return ret;
- }
- s->has_write_zeroes = false;
+ } else if (ret == -ENOTSUP)
+ s->has_fallocate_zero_range = false;
}
#endif
+ if (aiocb->aio_type & QEMU_AIO_BLKDEV) {
+ return handle_aiocb_write_zeroes_block(aiocb);
+ }
+
#ifdef CONFIG_FALLOCATE_PUNCH_HOLE
if (s->has_discard && s->has_fallocate) {
int ret = do_fallocate(s->fd,
--
2.7.4
On 03/27/2018 09:37 PM, zhenwei.pi wrote:
> since linux 4.9, block device supports fallocate. kernel issues
> block device zereout request and invalidates page cache. So
> ioctl(fd, FALLOC_FL_ZERO_RANGE...) is safer than ioctl(fd,
did you mean fallocate() in the first half of the sentence?
> BLKZEROOUT...). try to call do_fallocate, if failing, fallback.
>
> use new field "has_fallocate_zero_range" with default value as
> true. if do_fallocate returns -ENOTSUP, it will be set false.
>
> Signed-off-by: zhenwei.pi <zhenwei.pi@youruncloud.com>
> ---
> block/file-posix.c | 27 +++++++++++++++++----------
> 1 file changed, 17 insertions(+), 10 deletions(-)
>
This feels more like a feature for 2.13, than a bug fix that would fit
during freeze for 2.12.
> diff --git a/block/file-posix.c b/block/file-posix.c
> index d7fb772..842e940 100644
> --- a/block/file-posix.c
> +++ b/block/file-posix.c
> @@ -159,8 +159,9 @@ typedef struct BDRVRawState {
> bool discard_zeroes:1;
> bool use_linux_aio:1;
> bool page_cache_inconsistent:1;
> - bool has_fallocate;
> - bool needs_alignment;
> + bool has_fallocate:1;
> + bool has_fallocate_zero_range:1;
> + bool needs_alignment:1;
>
> PRManager *pr_mgr;
> } BDRVRawState;
> @@ -549,6 +550,7 @@ static int raw_open_common(BlockDriverState *bs, QDict *options,
>
> s->has_discard = true;
> s->has_write_zeroes = true;
> + s->has_fallocate_zero_range = true;
Is blindly setting this to true reasonable, given that...
> if ((bs->open_flags & BDRV_O_NOCACHE) != 0) {
> s->needs_alignment = true;
> }
> @@ -1365,10 +1367,6 @@ static ssize_t handle_aiocb_write_zeroes(RawPosixAIOData *aiocb)
> int64_t len;
> #endif
>
> - if (aiocb->aio_type & QEMU_AIO_BLKDEV) {
> - return handle_aiocb_write_zeroes_block(aiocb);
> - }
> -
> #ifdef CONFIG_XFS
> if (s->is_xfs) {
> return xfs_write_zeroes(s, aiocb->aio_offset, aiocb->aio_nbytes);
> @@ -1376,16 +1374,25 @@ static ssize_t handle_aiocb_write_zeroes(RawPosixAIOData *aiocb)
> #endif
>
> #ifdef CONFIG_FALLOCATE_ZERO_RANGE
> - if (s->has_write_zeroes) {
...later use is guarded by something learned at compile time?
> + /* since linux 4.9, block device supports fallocate. kernel issues
s/since/Since/
s/device supports/devices support/
s/kernel issues/The kernel issues a/
> + * block device zereout request and invalidates page cache. So
> + * ioctl(fd, FALLOC_FL_ZERO_RANGE...) is safer than ioctl(fd,
Same comment as on commit message; this looks like you meant fallocate
rather than ioctl on one of the two uses.
> + * BLKZEROOUT...). try to call do_fallocate, if failing, fallback.
s/try/Try/
s/if failing, fallback/and fall back if that fails/
> + */
> + if (s->has_fallocate_zero_range) {
> int ret = do_fallocate(s->fd, FALLOC_FL_ZERO_RANGE,
> aiocb->aio_offset, aiocb->aio_nbytes);
> - if (ret == 0 || ret != -ENOTSUP) {
> + if (ret == 0) {
> return ret;
> - }
> - s->has_write_zeroes = false;
> + } else if (ret == -ENOTSUP)
> + s->has_fallocate_zero_range = false;
> }
Before your patch, if we get any failure other than -ENOTSUP, we exit
immediately rather than attempting a fallback. Your code breaks that
paradigm, and blindly attempts the fallback even when the failure was
something like EIO.
> #endif
>
> + if (aiocb->aio_type & QEMU_AIO_BLKDEV) {
> + return handle_aiocb_write_zeroes_block(aiocb);
> + }
> +
> #ifdef CONFIG_FALLOCATE_PUNCH_HOLE
> if (s->has_discard && s->has_fallocate) {
> int ret = do_fallocate(s->fd,
>
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3266
Virtualization: qemu.org | libvirt.org
Hi,
This series seems to have some coding style problems. See output below for
more information:
Type: series
Message-id: 1522204637-29589-1-git-send-email-zhenwei.pi@youruncloud.com
Subject: [Qemu-devel] [PATCH] file-posix: Support fallocate for block device
=== TEST SCRIPT BEGIN ===
#!/bin/bash
BASE=base
n=1
total=$(git log --oneline $BASE.. | wc -l)
failed=0
git config --local diff.renamelimit 0
git config --local diff.renames True
git config --local diff.algorithm histogram
commits="$(git log --format=%H --reverse $BASE..)"
for c in $commits; do
echo "Checking PATCH $n/$total: $(git log -n 1 --format=%s $c)..."
if ! git show $c --format=email | ./scripts/checkpatch.pl --mailback -; then
failed=1
echo
fi
n=$((n+1))
done
exit $failed
=== TEST SCRIPT END ===
Updating 3c8cf5a9c21ff8782164d1def7f44bd888713384
Switched to a new branch 'test'
c955c08515 file-posix: Support fallocate for block device
=== OUTPUT BEGIN ===
Checking PATCH 1/1: file-posix: Support fallocate for block device...
ERROR: braces {} are necessary for all arms of this statement
#66: FILE: block/file-posix.c:1385:
+ if (ret == 0) {
[...]
- }
[...]
ERROR: braces {} are necessary for all arms of this statement
#70: FILE: block/file-posix.c:1387:
+ } else if (ret == -ENOTSUP)
[...]
total: 2 errors, 0 warnings, 57 lines checked
Your patch has style problems, please review. If any of these errors
are false positives report them to the maintainer, see
CHECKPATCH in MAINTAINERS.
=== OUTPUT END ===
Test command exited with code: 1
---
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