[XFS] Introduce two new mount options (nolargeio/largeio) to allow

filesystems to expose the filesystem stripe width in stat(2) rather than
the page cache size. This allows applications requiring high bandwidth to
easily determine the optimum I/O size for the underlying filesystem. The
default is to report the page cache size (i.e. "nolargeio").

SGI-PV: 942818
SGI-Modid: xfs-linux:xfs-kern:23830a

Signed-off-by: David Chinner <dgc@sgi.com>
Signed-off-by: Nathan Scott <nathans@sgi.com>

1 files changed, 11 insertions, 0 deletions

diff --git a/fs/xfs/xfs_vfsops.c b/fs/xfs/xfs_vfsops.c
index 9142351df515..7227baee8994 100644
--- a/fs/xfs/xfs_vfsops.c
+++ b/fs/xfs/xfs_vfsops.c
@@ -307,6 +307,9 @@ xfs_start_flags(
         if (ap->flags & XFSMNT_DIRSYNC)
                 mp->m_flags |= XFS_MOUNT_DIRSYNC;
 
+        if (ap->flags & XFSMNT_COMPAT_IOSIZE)
+                mp->m_flags |= XFS_MOUNT_COMPAT_IOSIZE;
+
         /*
          * no recovery flag requires a read-only mount
          */
@@ -1645,6 +1648,9 @@ xfs_vget(
 #define MNTOPT_64BITINODE   "inode64"   /* inodes can be allocated anywhere */
 #define MNTOPT_IKEEP    "ikeep"         /* do not free empty inode clusters */
 #define MNTOPT_NOIKEEP  "noikeep"       /* free empty inode clusters */
+#define MNTOPT_LARGEIO     "largeio"    /* report large I/O sizes in stat() */
+#define MNTOPT_NOLARGEIO   "nolargeio"  /* do not report large I/O sizes
+                                         * in stat(). */
 
 STATIC unsigned long
 suffix_strtoul(const char *cp, char **endp, unsigned int base)
@@ -1681,6 +1687,7 @@ xfs_parseargs(
         int                     dsunit, dswidth, vol_dsunit, vol_dswidth;
         int                     iosize;
 
+        args->flags |= XFSMNT_COMPAT_IOSIZE;
 #if 0   /* XXX: off by default, until some remaining issues ironed out */
         args->flags |= XFSMNT_IDELETE; /* default to on */
 #endif
@@ -1809,6 +1816,10 @@ xfs_parseargs(
                         args->flags &= ~XFSMNT_IDELETE;
                 } else if (!strcmp(this_char, MNTOPT_NOIKEEP)) {
                         args->flags |= XFSMNT_IDELETE;
+                } else if (!strcmp(this_char, MNTOPT_LARGEIO)) {
+                        args->flags &= ~XFSMNT_COMPAT_IOSIZE;
+                } else if (!strcmp(this_char, MNTOPT_NOLARGEIO)) {
+                        args->flags |= XFSMNT_COMPAT_IOSIZE;
                 } else if (!strcmp(this_char, "osyncisdsync")) {
                         /* no-op, this is now the default */
 printk("XFS: osyncisdsync is now the default, option is deprecated.\n");