[PATCH v3] fiemap: add a nosync option

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/[email protected]/

Signed-off-by: Pankaj Raghav <[email protected]>
---
Changes since v2:
- Add this option to the man page (Darrick)
- Add more information about this flag in the help.
Changes since v1:
- Change '-s' to '-e' to match xfs_bmap (Christoph).

 io/fiemap.c       | 9 +++++++--
 man/man8/xfs_io.8 | 2 +-
 2 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/io/fiemap.c b/io/fiemap.c
index b41f71bf..cf3a1b3e 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"
+" -e -- obtains also delayed allocation extents by not using 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:ev")) != EOF) {
 		switch (c) {
 		case 'a':
 			fiemap_flags |= FIEMAP_FLAG_XATTR;
@@ -253,6 +254,10 @@ fiemap_f(
 		case 'n':
 			max_extents = atoi(optarg);
 			break;
+		case 'e':
+			/* 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 = _("[-alev] [-n nx] [offset [len]]");
 	fiemap_cmd.oneline = _("print block mapping for a file");
 	fiemap_cmd.help = fiemap_help;
 
diff --git a/man/man8/xfs_io.8 b/man/man8/xfs_io.8
index 61defcc3..a3ddab02 100644
--- a/man/man8/xfs_io.8
+++ b/man/man8/xfs_io.8
@@ -353,7 +353,7 @@ Prints the block mapping for the current open file. Refer to the
 .BR xfs_bmap (8)
 manual page for complete documentation.
 .TP
-.BI "fiemap [ \-alv ] [ \-n " nx " ] [ " offset " [ " len " ]]"
+.BI "fiemap [ \-alev ] [ \-n " nx " ] [ " offset " [ " len " ]]"
 Prints the block mapping for the current open file using the fiemap
 ioctl.  Options behave as described in the
 .BR xfs_bmap (8)

base-commit: e80b048d87fdc5735e0d03ae29b497b402ea8bbe
-- 
2.51.2