Add per-io RWF_DONTCACHE support flag to preadv2()
This enables xfs_io to perform buffered-io read which can drop the page
cache folios after reading.
e.g. xfs_io -c "pread -U -V 1 0 16K" /mnt/f1
Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@xxxxxxxxx>
---
io/pread.c | 12 ++++++++++--
man/man8/xfs_io.8 | 8 +++++++-
2 files changed, 17 insertions(+), 3 deletions(-)
diff --git a/io/pread.c b/io/pread.c
index 782f2a36..64c28784 100644
--- a/io/pread.c
+++ b/io/pread.c
@@ -38,6 +38,9 @@ pread_help(void)
" -Z N -- zeed the random number generator (used when reading randomly)\n"
" (heh, zorry, the -s/-S arguments were already in use in pwrite)\n"
" -V N -- use vectored IO with N iovecs of blocksize each (preadv)\n"
+#ifdef HAVE_PWRITEV2
+" -U -- Perform the preadv2() with Uncached/RWF_DONTCACHE\n"
+#endif
"\n"
" When in \"random\" mode, the number of read operations will equal the\n"
" number required to do a complete forward/backward scan of the range.\n"
@@ -388,7 +391,7 @@ pread_f(
init_cvtnum(&fsblocksize, &fssectsize);
bsize = fsblocksize;
- while ((c = getopt(argc, argv, "b:BCFRquvV:Z:")) != EOF) {
+ while ((c = getopt(argc, argv, "b:BCFRquUvV:Z:")) != EOF) {
switch (c) {
case 'b':
tmp = cvtnum(fsblocksize, fssectsize, optarg);
@@ -417,6 +420,11 @@ pread_f(
case 'u':
uflag = 1;
break;
+#ifdef HAVE_PREADV2
+ case 'U':
+ preadv2_flags |= RWF_DONTCACHE;
+ break;
+#endif
case 'v':
vflag = 1;
break;
@@ -514,7 +522,7 @@ pread_init(void)
pread_cmd.argmin = 2;
pread_cmd.argmax = -1;
pread_cmd.flags = CMD_NOMAP_OK | CMD_FOREIGN_OK;
- pread_cmd.args = _("[-b bs] [-qv] [-i N] [-FBR [-Z N]] off len");
+ pread_cmd.args = _("[-b bs] [-qUv] [-i N] [-FBR [-Z N]] off len");
pread_cmd.oneline = _("reads a number of bytes at a specified offset");
pread_cmd.help = pread_help;
diff --git a/man/man8/xfs_io.8 b/man/man8/xfs_io.8
index 47af5232..df508054 100644
--- a/man/man8/xfs_io.8
+++ b/man/man8/xfs_io.8
@@ -200,7 +200,7 @@ option will set the file permissions to read-write (0644). This allows xfs_io to
set up mismatches between the file permissions and the open file descriptor
read/write mode to exercise permission checks inside various syscalls.
.TP
-.BI "pread [ \-b " bsize " ] [ \-qv ] [ \-FBR [ \-Z " seed " ] ] [ \-V " vectors " ] " "offset length"
+.BI "pread [ \-b " bsize " ] [ \-qUv ] [ \-FBR [ \-Z " seed " ] ] [ \-V " vectors " ] " "offset length"
Reads a range of bytes in a specified blocksize from the given
.IR offset .
.RS 1.0i
@@ -214,6 +214,12 @@ requests will be split. The default blocksize is 4096 bytes.
.B \-q
quiet mode, do not write anything to standard output.
.TP
+.B \-U
+Perform the
+.BR preadv2 (2)
+call with
+.IR RWF_DONTCACHE .
+.TP
.B \-v
dump the contents of the buffer after reading,
by default only the count of bytes actually read is dumped.
--
2.48.1
