From: Darrick J. Wong <darrick.wong@oracle.com>
Date: Tue, 25 Oct 2016 22:14:33 +0000 (-0700)
Subject: xfs_io: provide long-format help for falloc
X-Git-Tag: v4.9.0-rc1~45
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=0c2ed80a3590e30a2eebfa89f4d43080bf850abe;p=thirdparty%2Fxfsprogs-dev.git

xfs_io: provide long-format help for falloc

Provide long-format help for falloc so that users can learn about
the command.

Note for xfstest writers: If you need to check that a particular
fallocate mode works (-c/-i/-p/-u) on a given filesystem, you should
call _require_xfs_io_command with the falloc subcommand directly, (i.e.
_require_xfs_io_command funshare) because the subcommands are
special-cased to actually try the command.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---

diff --git a/io/prealloc.c b/io/prealloc.c
index 713ea7bcb..7f5c20026 100644
--- a/io/prealloc.c
+++ b/io/prealloc.c
@@ -164,6 +164,26 @@ zero_f(
 
 
 #if defined (HAVE_FALLOCATE)
+static void
+falloc_help(void)
+{
+	printf(_(
+"\n"
+" modifies space associated with part of a file via fallocate"
+"\n"
+" Example:\n"
+" 'falloc 0 1m' - fills all holes within the first megabyte\n"
+"\n"
+" falloc uses the fallocate system call to alter space allocations in the\n"
+" open file.  The following operations are supported:\n"
+" All the file offsets are in units of bytes.\n"
+" -c -- collapses the given range.\n"
+" -i -- inserts a hole into the given range of the file.\n"
+" -k -- do not change file size.\n"
+" -p -- unmap the given range from the file.\n"
+"\n"));
+}
+
 static int
 fallocate_f(
 	int		argc,
@@ -349,6 +369,7 @@ prealloc_init(void)
 	falloc_cmd.args = _("[-c] [-k] [-p] off len");
 	falloc_cmd.oneline =
 	_("allocates space associated with part of a file via fallocate");
+	falloc_cmd.help = falloc_help;
 	add_command(&falloc_cmd);
 
 	fpunch_cmd.name = "fpunch";