[PATCH] mkfs.xfs: always use underlying fs sector size when mkfs'ing a file

Eric Sandeen
2015-06-17T23:26:39Z

If we are mkfs'ing a file, and that file is on a 4k sector filesystem,
we should make the fs image file with the same sector size, or things
may fail when they try to do direct IO in 512 byte chunks (depending
on whether it is a 512e or "hard" 4k device).

Earlier commits attempted this to some degree:

5a7d59 xfsprogs: try to handle mkfs of a file on 4k sector device
3800a2 mkfs.xfs: don't call blkid_get_topology on existing regular files

but inexplicably missed the case where mkfs.xfs with "-d file" was
specified.

One more try; in get_topology(), try to get the underlying fs sector
size in *all* cases where we are mkfs'ing a file, and set the sector size
accordingly.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
---

(This does it for 512e as well as hard 4k drives, but I think that's
probably ok? If not, perhaps we should go further and attempt to
discern logical and physical sectors for the device under the
filesystem. Is it worth it? Not sure it is.)

diff --git a/mkfs/xfs_mkfs.c b/mkfs/xfs_mkfs.c
index e2a052d..e44c390 100644
--- a/mkfs/xfs_mkfs.c
+++ b/mkfs/xfs_mkfs.c
@@ -462,31 +462,34 @@ static void get_topology(
struct fs_topology *ft,
int force_overwrite)
{
- if (!xi->disfile) {
- char *dfile = xi->volname ? xi->volname : xi->dname;
- struct stat statbuf;
+ struct stat statbuf;
+ char *dfile = xi->volname ? xi->volname : xi->dname;

- /*
- * If our target is a regular file, and xi->disfile isn't
- * set (i.e. no "-d file" invocation), use platform_findsizes
- * to try to obtain the underlying filesystem's requirements
- * for direct IO; we'll set our sector size to that if possible.
- */
- if (!stat(dfile, &statbuf) && S_ISREG(statbuf.st_mode)) {
- int fd;
- long long dummy;
-
- fd = open(dfile, O_RDONLY);
- if (fd >= 0) {
- platform_findsizes(dfile, fd, &dummy,
- &ft->lsectorsize);
- close(fd);
- }
- } else {
- blkid_get_topology(dfile, &ft->dsunit, &ft->dswidth,
- &ft->lsectorsize, &ft->psectorsize,
- force_overwrite);
+ /*
+ * If our target is a regular file, use platform_findsizes
+ * to try to obtain the underlying filesystem's requirements
+ * for direct IO; we'll set our sector size to that if possible.
+ */
+ if (xi->disfile ||
+ (!stat(dfile, &statbuf) && S_ISREG(statbuf.st_mode))) {
+ int fd;
+ int flags = O_RDONLY;
+ long long dummy;
+
+ /* with xi->disfile we may not have the file yet! */
+ if (xi->disfile)
+ flags |= O_CREAT;
+
+ fd = open(dfile, flags, 0666);
+ if (fd >= 0) {
+ platform_findsizes(dfile, fd, &dummy, &ft->lsectorsize);
+ close (fd);
}
+
+ } else {
+ blkid_get_topology(dfile, &ft->dsunit, &ft->dswidth,
+ &ft->lsectorsize, &ft->psectorsize,
+ force_overwrite);
}

if (xi->rtname && !xi->risfile) {