From: Zhang Yi <yi.zh...@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.zh...@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
