* [PATCH xfsprogs v2] xfs_io: add FALLOC_FL_WRITE_ZEROES support
@ 2025-08-13 2:42 Zhang Yi
2025-08-14 16:54 ` Darrick J. Wong
0 siblings, 1 reply; 4+ messages in thread
From: Zhang Yi @ 2025-08-13 2:42 UTC (permalink / raw)
To: linux-fsdevel, linux-block, dm-devel, linux-nvme, linux-scsi,
linux-xfs
Cc: linux-kernel, linux-api, hch, tytso, djwong, bmarzins, chaitanyak,
shinichiro.kawasaki, brauner, martin.petersen, yi.zhang, yi.zhang,
chengzhihao1, yukuai3, yangerkun
From: Zhang Yi <yi.zhang@huawei.com>
The Linux kernel (since version 6.17) supports FALLOC_FL_WRITE_ZEROES in
fallocate(2). Add support for FALLOC_FL_WRITE_ZEROES support to the
fallocate utility by introducing a new 'fwzero' command in the xfs_io
tool.
Link: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=278c7d9b5e0c
Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
---
v1->v2:
- Minor description modification to align with the kernel.
io/prealloc.c | 36 ++++++++++++++++++++++++++++++++++++
man/man8/xfs_io.8 | 6 ++++++
2 files changed, 42 insertions(+)
diff --git a/io/prealloc.c b/io/prealloc.c
index 8e968c9f..9a64bf53 100644
--- a/io/prealloc.c
+++ b/io/prealloc.c
@@ -30,6 +30,10 @@
#define FALLOC_FL_UNSHARE_RANGE 0x40
#endif
+#ifndef FALLOC_FL_WRITE_ZEROES
+#define FALLOC_FL_WRITE_ZEROES 0x80
+#endif
+
static cmdinfo_t allocsp_cmd;
static cmdinfo_t freesp_cmd;
static cmdinfo_t resvsp_cmd;
@@ -41,6 +45,7 @@ static cmdinfo_t fcollapse_cmd;
static cmdinfo_t finsert_cmd;
static cmdinfo_t fzero_cmd;
static cmdinfo_t funshare_cmd;
+static cmdinfo_t fwzero_cmd;
static int
offset_length(
@@ -377,6 +382,27 @@ funshare_f(
return 0;
}
+static int
+fwzero_f(
+ int argc,
+ char **argv)
+{
+ xfs_flock64_t segment;
+ int mode = FALLOC_FL_WRITE_ZEROES;
+
+ if (!offset_length(argv[1], argv[2], &segment)) {
+ exitcode = 1;
+ return 0;
+ }
+
+ if (fallocate(file->fd, mode, segment.l_start, segment.l_len)) {
+ perror("fallocate");
+ exitcode = 1;
+ return 0;
+ }
+ return 0;
+}
+
void
prealloc_init(void)
{
@@ -489,4 +515,14 @@ prealloc_init(void)
funshare_cmd.oneline =
_("unshares shared blocks within the range");
add_command(&funshare_cmd);
+
+ fwzero_cmd.name = "fwzero";
+ fwzero_cmd.cfunc = fwzero_f;
+ fwzero_cmd.argmin = 2;
+ fwzero_cmd.argmax = 2;
+ fwzero_cmd.flags = CMD_NOMAP_OK | CMD_FOREIGN_OK;
+ fwzero_cmd.args = _("off len");
+ fwzero_cmd.oneline =
+ _("zeroes space and eliminates holes by allocating and submitting write zeroes");
+ add_command(&fwzero_cmd);
}
diff --git a/man/man8/xfs_io.8 b/man/man8/xfs_io.8
index b0dcfdb7..0a673322 100644
--- a/man/man8/xfs_io.8
+++ b/man/man8/xfs_io.8
@@ -550,6 +550,12 @@ With the
.B -k
option, use the FALLOC_FL_KEEP_SIZE flag as well.
.TP
+.BI fwzero " offset length"
+Call fallocate with FALLOC_FL_WRITE_ZEROES flag as described in the
+.BR fallocate (2)
+manual page to allocate and zero blocks within the range by submitting write
+zeroes.
+.TP
.BI zero " offset length"
Call xfsctl with
.B XFS_IOC_ZERO_RANGE
--
2.39.2
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH xfsprogs v2] xfs_io: add FALLOC_FL_WRITE_ZEROES support
2025-08-13 2:42 [PATCH xfsprogs v2] xfs_io: add FALLOC_FL_WRITE_ZEROES support Zhang Yi
@ 2025-08-14 16:54 ` Darrick J. Wong
2025-08-15 9:59 ` Zhang Yi
0 siblings, 1 reply; 4+ messages in thread
From: Darrick J. Wong @ 2025-08-14 16:54 UTC (permalink / raw)
To: Zhang Yi
Cc: linux-fsdevel, linux-block, dm-devel, linux-nvme, linux-scsi,
linux-xfs, linux-kernel, linux-api, hch, tytso, bmarzins,
chaitanyak, shinichiro.kawasaki, brauner, martin.petersen,
yi.zhang, chengzhihao1, yukuai3, yangerkun
On Wed, Aug 13, 2025 at 10:42:50AM +0800, Zhang Yi wrote:
> From: Zhang Yi <yi.zhang@huawei.com>
>
> The Linux kernel (since version 6.17) supports FALLOC_FL_WRITE_ZEROES in
> fallocate(2). Add support for FALLOC_FL_WRITE_ZEROES support to the
> fallocate utility by introducing a new 'fwzero' command in the xfs_io
> tool.
>
> Link: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=278c7d9b5e0c
> Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
> ---
> v1->v2:
> - Minor description modification to align with the kernel.
>
> io/prealloc.c | 36 ++++++++++++++++++++++++++++++++++++
> man/man8/xfs_io.8 | 6 ++++++
> 2 files changed, 42 insertions(+)
>
> diff --git a/io/prealloc.c b/io/prealloc.c
> index 8e968c9f..9a64bf53 100644
> --- a/io/prealloc.c
> +++ b/io/prealloc.c
> @@ -30,6 +30,10 @@
> #define FALLOC_FL_UNSHARE_RANGE 0x40
> #endif
>
> +#ifndef FALLOC_FL_WRITE_ZEROES
> +#define FALLOC_FL_WRITE_ZEROES 0x80
> +#endif
> +
> static cmdinfo_t allocsp_cmd;
> static cmdinfo_t freesp_cmd;
> static cmdinfo_t resvsp_cmd;
> @@ -41,6 +45,7 @@ static cmdinfo_t fcollapse_cmd;
> static cmdinfo_t finsert_cmd;
> static cmdinfo_t fzero_cmd;
> static cmdinfo_t funshare_cmd;
> +static cmdinfo_t fwzero_cmd;
>
> static int
> offset_length(
> @@ -377,6 +382,27 @@ funshare_f(
> return 0;
> }
>
> +static int
> +fwzero_f(
> + int argc,
> + char **argv)
> +{
> + xfs_flock64_t segment;
> + int mode = FALLOC_FL_WRITE_ZEROES;
Shouldn't this take a -k to add FALLOC_FL_KEEP_SIZE like fzero?
(The code otherwise looks fine to me)
--D
> +
> + if (!offset_length(argv[1], argv[2], &segment)) {
> + exitcode = 1;
> + return 0;
> + }
> +
> + if (fallocate(file->fd, mode, segment.l_start, segment.l_len)) {
> + perror("fallocate");
> + exitcode = 1;
> + return 0;
> + }
> + return 0;
> +}
> +
> void
> prealloc_init(void)
> {
> @@ -489,4 +515,14 @@ prealloc_init(void)
> funshare_cmd.oneline =
> _("unshares shared blocks within the range");
> add_command(&funshare_cmd);
> +
> + fwzero_cmd.name = "fwzero";
> + fwzero_cmd.cfunc = fwzero_f;
> + fwzero_cmd.argmin = 2;
> + fwzero_cmd.argmax = 2;
> + fwzero_cmd.flags = CMD_NOMAP_OK | CMD_FOREIGN_OK;
> + fwzero_cmd.args = _("off len");
> + fwzero_cmd.oneline =
> + _("zeroes space and eliminates holes by allocating and submitting write zeroes");
> + add_command(&fwzero_cmd);
> }
> diff --git a/man/man8/xfs_io.8 b/man/man8/xfs_io.8
> index b0dcfdb7..0a673322 100644
> --- a/man/man8/xfs_io.8
> +++ b/man/man8/xfs_io.8
> @@ -550,6 +550,12 @@ With the
> .B -k
> option, use the FALLOC_FL_KEEP_SIZE flag as well.
> .TP
> +.BI fwzero " offset length"
> +Call fallocate with FALLOC_FL_WRITE_ZEROES flag as described in the
> +.BR fallocate (2)
> +manual page to allocate and zero blocks within the range by submitting write
> +zeroes.
> +.TP
> .BI zero " offset length"
> Call xfsctl with
> .B XFS_IOC_ZERO_RANGE
> --
> 2.39.2
>
>
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH xfsprogs v2] xfs_io: add FALLOC_FL_WRITE_ZEROES support
2025-08-14 16:54 ` Darrick J. Wong
@ 2025-08-15 9:59 ` Zhang Yi
2025-08-15 14:42 ` Darrick J. Wong
0 siblings, 1 reply; 4+ messages in thread
From: Zhang Yi @ 2025-08-15 9:59 UTC (permalink / raw)
To: Darrick J. Wong
Cc: linux-fsdevel, linux-block, dm-devel, linux-nvme, linux-scsi,
linux-xfs, linux-kernel, linux-api, hch, tytso, bmarzins,
chaitanyak, shinichiro.kawasaki, brauner, martin.petersen,
yi.zhang, chengzhihao1, yukuai3, yangerkun
On 2025/8/15 0:54, Darrick J. Wong wrote:
> On Wed, Aug 13, 2025 at 10:42:50AM +0800, Zhang Yi wrote:
>> From: Zhang Yi <yi.zhang@huawei.com>
>>
>> The Linux kernel (since version 6.17) supports FALLOC_FL_WRITE_ZEROES in
>> fallocate(2). Add support for FALLOC_FL_WRITE_ZEROES support to the
>> fallocate utility by introducing a new 'fwzero' command in the xfs_io
>> tool.
>>
>> Link: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=278c7d9b5e0c
>> Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
>> ---
>> v1->v2:
>> - Minor description modification to align with the kernel.
>>
>> io/prealloc.c | 36 ++++++++++++++++++++++++++++++++++++
>> man/man8/xfs_io.8 | 6 ++++++
>> 2 files changed, 42 insertions(+)
>>
>> diff --git a/io/prealloc.c b/io/prealloc.c
>> index 8e968c9f..9a64bf53 100644
>> --- a/io/prealloc.c
>> +++ b/io/prealloc.c
>> @@ -30,6 +30,10 @@
>> #define FALLOC_FL_UNSHARE_RANGE 0x40
>> #endif
>>
>> +#ifndef FALLOC_FL_WRITE_ZEROES
>> +#define FALLOC_FL_WRITE_ZEROES 0x80
>> +#endif
>> +
>> static cmdinfo_t allocsp_cmd;
>> static cmdinfo_t freesp_cmd;
>> static cmdinfo_t resvsp_cmd;
>> @@ -41,6 +45,7 @@ static cmdinfo_t fcollapse_cmd;
>> static cmdinfo_t finsert_cmd;
>> static cmdinfo_t fzero_cmd;
>> static cmdinfo_t funshare_cmd;
>> +static cmdinfo_t fwzero_cmd;
>>
>> static int
>> offset_length(
>> @@ -377,6 +382,27 @@ funshare_f(
>> return 0;
>> }
>>
>> +static int
>> +fwzero_f(
>> + int argc,
>> + char **argv)
>> +{
>> + xfs_flock64_t segment;
>> + int mode = FALLOC_FL_WRITE_ZEROES;
>
> Shouldn't this take a -k to add FALLOC_FL_KEEP_SIZE like fzero?
>
Since allocating blocks with written extents beyond the inode size
is not permitted, the FALLOC_FL_WRITE_ZEROES flag cannot be used
together with the FALLOC_FL_KEEP_SIZE.
Thanks,
Yi.
> (The code otherwise looks fine to me)
>
> --D
>
>> +
>> + if (!offset_length(argv[1], argv[2], &segment)) {
>> + exitcode = 1;
>> + return 0;
>> + }
>> +
>> + if (fallocate(file->fd, mode, segment.l_start, segment.l_len)) {
>> + perror("fallocate");
>> + exitcode = 1;
>> + return 0;
>> + }
>> + return 0;
>> +}
>> +
>> void
>> prealloc_init(void)
>> {
>> @@ -489,4 +515,14 @@ prealloc_init(void)
>> funshare_cmd.oneline =
>> _("unshares shared blocks within the range");
>> add_command(&funshare_cmd);
>> +
>> + fwzero_cmd.name = "fwzero";
>> + fwzero_cmd.cfunc = fwzero_f;
>> + fwzero_cmd.argmin = 2;
>> + fwzero_cmd.argmax = 2;
>> + fwzero_cmd.flags = CMD_NOMAP_OK | CMD_FOREIGN_OK;
>> + fwzero_cmd.args = _("off len");
>> + fwzero_cmd.oneline =
>> + _("zeroes space and eliminates holes by allocating and submitting write zeroes");
>> + add_command(&fwzero_cmd);
>> }
>> diff --git a/man/man8/xfs_io.8 b/man/man8/xfs_io.8
>> index b0dcfdb7..0a673322 100644
>> --- a/man/man8/xfs_io.8
>> +++ b/man/man8/xfs_io.8
>> @@ -550,6 +550,12 @@ With the
>> .B -k
>> option, use the FALLOC_FL_KEEP_SIZE flag as well.
>> .TP
>> +.BI fwzero " offset length"
>> +Call fallocate with FALLOC_FL_WRITE_ZEROES flag as described in the
>> +.BR fallocate (2)
>> +manual page to allocate and zero blocks within the range by submitting write
>> +zeroes.
>> +.TP
>> .BI zero " offset length"
>> Call xfsctl with
>> .B XFS_IOC_ZERO_RANGE
>> --
>> 2.39.2
>>
>>
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH xfsprogs v2] xfs_io: add FALLOC_FL_WRITE_ZEROES support
2025-08-15 9:59 ` Zhang Yi
@ 2025-08-15 14:42 ` Darrick J. Wong
0 siblings, 0 replies; 4+ messages in thread
From: Darrick J. Wong @ 2025-08-15 14:42 UTC (permalink / raw)
To: Zhang Yi
Cc: linux-fsdevel, linux-block, dm-devel, linux-nvme, linux-scsi,
linux-xfs, linux-kernel, linux-api, hch, tytso, bmarzins,
chaitanyak, shinichiro.kawasaki, brauner, martin.petersen,
yi.zhang, chengzhihao1, yukuai3, yangerkun
On Fri, Aug 15, 2025 at 05:59:01PM +0800, Zhang Yi wrote:
> On 2025/8/15 0:54, Darrick J. Wong wrote:
> > On Wed, Aug 13, 2025 at 10:42:50AM +0800, Zhang Yi wrote:
> >> From: Zhang Yi <yi.zhang@huawei.com>
> >>
> >> The Linux kernel (since version 6.17) supports FALLOC_FL_WRITE_ZEROES in
> >> fallocate(2). Add support for FALLOC_FL_WRITE_ZEROES support to the
> >> fallocate utility by introducing a new 'fwzero' command in the xfs_io
> >> tool.
> >>
> >> Link: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=278c7d9b5e0c
> >> Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
> >> ---
> >> v1->v2:
> >> - Minor description modification to align with the kernel.
> >>
> >> io/prealloc.c | 36 ++++++++++++++++++++++++++++++++++++
> >> man/man8/xfs_io.8 | 6 ++++++
> >> 2 files changed, 42 insertions(+)
> >>
> >> diff --git a/io/prealloc.c b/io/prealloc.c
> >> index 8e968c9f..9a64bf53 100644
> >> --- a/io/prealloc.c
> >> +++ b/io/prealloc.c
> >> @@ -30,6 +30,10 @@
> >> #define FALLOC_FL_UNSHARE_RANGE 0x40
> >> #endif
> >>
> >> +#ifndef FALLOC_FL_WRITE_ZEROES
> >> +#define FALLOC_FL_WRITE_ZEROES 0x80
> >> +#endif
> >> +
> >> static cmdinfo_t allocsp_cmd;
> >> static cmdinfo_t freesp_cmd;
> >> static cmdinfo_t resvsp_cmd;
> >> @@ -41,6 +45,7 @@ static cmdinfo_t fcollapse_cmd;
> >> static cmdinfo_t finsert_cmd;
> >> static cmdinfo_t fzero_cmd;
> >> static cmdinfo_t funshare_cmd;
> >> +static cmdinfo_t fwzero_cmd;
> >>
> >> static int
> >> offset_length(
> >> @@ -377,6 +382,27 @@ funshare_f(
> >> return 0;
> >> }
> >>
> >> +static int
> >> +fwzero_f(
> >> + int argc,
> >> + char **argv)
> >> +{
> >> + xfs_flock64_t segment;
> >> + int mode = FALLOC_FL_WRITE_ZEROES;
> >
> > Shouldn't this take a -k to add FALLOC_FL_KEEP_SIZE like fzero?
> >
>
> Since allocating blocks with written extents beyond the inode size
> is not permitted, the FALLOC_FL_WRITE_ZEROES flag cannot be used
> together with the FALLOC_FL_KEEP_SIZE.
Heh, apparently I didn't read the manpage well enough.
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
--D
> Thanks,
> Yi.
>
> > (The code otherwise looks fine to me)
> >
> > --D
> >
> >> +
> >> + if (!offset_length(argv[1], argv[2], &segment)) {
> >> + exitcode = 1;
> >> + return 0;
> >> + }
> >> +
> >> + if (fallocate(file->fd, mode, segment.l_start, segment.l_len)) {
> >> + perror("fallocate");
> >> + exitcode = 1;
> >> + return 0;
> >> + }
> >> + return 0;
> >> +}
> >> +
> >> void
> >> prealloc_init(void)
> >> {
> >> @@ -489,4 +515,14 @@ prealloc_init(void)
> >> funshare_cmd.oneline =
> >> _("unshares shared blocks within the range");
> >> add_command(&funshare_cmd);
> >> +
> >> + fwzero_cmd.name = "fwzero";
> >> + fwzero_cmd.cfunc = fwzero_f;
> >> + fwzero_cmd.argmin = 2;
> >> + fwzero_cmd.argmax = 2;
> >> + fwzero_cmd.flags = CMD_NOMAP_OK | CMD_FOREIGN_OK;
> >> + fwzero_cmd.args = _("off len");
> >> + fwzero_cmd.oneline =
> >> + _("zeroes space and eliminates holes by allocating and submitting write zeroes");
> >> + add_command(&fwzero_cmd);
> >> }
> >> diff --git a/man/man8/xfs_io.8 b/man/man8/xfs_io.8
> >> index b0dcfdb7..0a673322 100644
> >> --- a/man/man8/xfs_io.8
> >> +++ b/man/man8/xfs_io.8
> >> @@ -550,6 +550,12 @@ With the
> >> .B -k
> >> option, use the FALLOC_FL_KEEP_SIZE flag as well.
> >> .TP
> >> +.BI fwzero " offset length"
> >> +Call fallocate with FALLOC_FL_WRITE_ZEROES flag as described in the
> >> +.BR fallocate (2)
> >> +manual page to allocate and zero blocks within the range by submitting write
> >> +zeroes.
> >> +.TP
> >> .BI zero " offset length"
> >> Call xfsctl with
> >> .B XFS_IOC_ZERO_RANGE
> >> --
> >> 2.39.2
> >>
> >>
>
>
^ permalink raw reply [flat|nested] 4+ messages in thread
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2025-08-13 2:42 [PATCH xfsprogs v2] xfs_io: add FALLOC_FL_WRITE_ZEROES support Zhang Yi
2025-08-14 16:54 ` Darrick J. Wong
2025-08-15 9:59 ` Zhang Yi
2025-08-15 14:42 ` Darrick J. Wong
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