[PATCH 1/2] libxfs: make platform_set_blocksize optional with directio

["Darrick J. Wong" <djwong@kernel.org>]

From: Darrick J. Wong <djwong@kernel.org>

If we're accessing the block device with directio (and hence bypassing
the page cache), then don't fail on BLKBSZSET not working.  We don't
care what happens to the pagecache bufferheads.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
---
 libxfs/init.c |    8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)


diff --git a/libxfs/init.c b/libxfs/init.c
index fda36ba0f7d..ce6e62cde94 100644
--- a/libxfs/init.c
+++ b/libxfs/init.c
@@ -125,10 +125,14 @@ libxfs_device_open(char *path, int creat, int xflags, int setblksize)
 	}
 
 	if (!readonly && setblksize && (statb.st_mode & S_IFMT) == S_IFBLK) {
-		if (setblksize == 1)
+		if (setblksize == 1) {
 			/* use the default blocksize */
 			(void)platform_set_blocksize(fd, path, statb.st_rdev, XFS_MIN_SECTORSIZE, 0);
-		else {
+		} else if (dio) {
+			/* try to use the given explicit blocksize */
+			(void)platform_set_blocksize(fd, path, statb.st_rdev,
+					setblksize, 0);
+		} else {
 			/* given an explicit blocksize to use */
 			if (platform_set_blocksize(fd, path, statb.st_rdev, setblksize, 1))
 			    exit(1);