[PATCH] fiemap: add a nosync option

[PATCH] fiemap: add a nosync option

[Pankaj Raghav]

io/fiemap adds FIEMAP_FLAG_SYNC by default. There are some test cases
where adding this flag might have an undesired side effect on the
results [1].

Add an option that does not pass FIEMAP_FLAG_SYNC flag.

[1] https://lore.kernel.org/linux-xfs/ca21b3c4-e1df-4ba7-8e9c-5d221337c86b@huaweicloud.com/

Signed-off-by: Pankaj Raghav <p.raghav@samsung.com>
---
 io/fiemap.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/io/fiemap.c b/io/fiemap.c
index b41f71bf..7aa8868d 100644
--- a/io/fiemap.c
+++ b/io/fiemap.c
@@ -36,6 +36,7 @@ fiemap_help(void)
 " -a -- prints the attribute fork map instead of the data fork.\n"
 " -l -- also displays the length of each extent in 512-byte blocks.\n"
 " -n -- query n extents.\n"
+" -s -- do not use FIEMAP_FLAG_SYNC.\n"
 " -v -- Verbose information\n"
 " offset is the starting offset to map, and is optional.  If offset is\n"
 " specified, mapping length may (optionally) be specified as well."
@@ -242,7 +243,7 @@ fiemap_f(
 
 	init_cvtnum(&fsblocksize, &fssectsize);
 
-	while ((c = getopt(argc, argv, "aln:v")) != EOF) {
+	while ((c = getopt(argc, argv, "aln:sv")) != EOF) {
 		switch (c) {
 		case 'a':
 			fiemap_flags |= FIEMAP_FLAG_XATTR;
@@ -253,6 +254,10 @@ fiemap_f(
 		case 'n':
 			max_extents = atoi(optarg);
 			break;
+		case 's':
+			/* nosync */
+			fiemap_flags &= ~(FIEMAP_FLAG_SYNC);
+			break;
 		case 'v':
 			vflag++;
 			break;
@@ -393,7 +398,7 @@ fiemap_init(void)
 	fiemap_cmd.argmin = 0;
 	fiemap_cmd.argmax = -1;
 	fiemap_cmd.flags = CMD_NOMAP_OK | CMD_FOREIGN_OK;
-	fiemap_cmd.args = _("[-alv] [-n nx] [offset [len]]");
+	fiemap_cmd.args = _("[-alsv] [-n nx] [offset [len]]");
 	fiemap_cmd.oneline = _("print block mapping for a file");
 	fiemap_cmd.help = fiemap_help;
 

base-commit: e80b048d87fdc5735e0d03ae29b497b402ea8bbe
-- 
2.51.2

Re: [PATCH] fiemap: add a nosync option

[Christoph Hellwig]

On Tue, Jul 14, 2026 at 12:53:14PM +0200, Pankaj Raghav wrote:
> diff --git a/io/fiemap.c b/io/fiemap.c
> index b41f71bf..7aa8868d 100644
> --- a/io/fiemap.c
> +++ b/io/fiemap.c
> @@ -36,6 +36,7 @@ fiemap_help(void)
>  " -a -- prints the attribute fork map instead of the data fork.\n"
>  " -l -- also displays the length of each extent in 512-byte blocks.\n"
>  " -n -- query n extents.\n"
> +" -s -- do not use FIEMAP_FLAG_SYNC.\n"

The xfs_io manpage refers to the xfs_bmap man page for the argument,
and xfs_bmap already supports a -e option to skip the sync.  Maybe we
should match that for consistency?

Otherwise this looks good.