[XFS] Add support for allocating additional file space in

stripe width sized chunks. A new fstab/mount option,
"swalloc" has been defined. If specified when mounting
a striped file system, allocation requests will be
rounded up to a stripe width if the file size is >= stripe
width, and the data is being appended to eof. The
'swalloc' option is "off" by default.

SGI Modid: xfs-linux:xfs-kern:171710a

fs/xfs/xfs_clnt.h

@@ -100,5 +100,7 @@ struct xfs_mount_args {
 #define XFSMNT_DMAPI		0x02000000	/* enable dmapi/xdsm */
 #define XFSMNT_NOLOGFLUSH	0x04000000	/* Don't flush for log blocks */
 #define XFSMNT_IDELETE		0x08000000	/* inode cluster delete */
+#define XFSMNT_SWALLOC		0x10000000	/* turn on stripe width
+						 * allocation */
 
 #endif	/* __XFS_CLNT_H__ */

fs/xfs/xfs_iomap.c

@@ -616,12 +616,31 @@ xfs_iomap_write_delay(
 	nimaps = XFS_WRITE_IMAPS;
 	firstblock = NULLFSBLOCK;
 
+	/*
+	 * If mounted with the "-o swalloc" option, roundup the allocation
+	 * request to a stripe width boundary if the file size is >=
+	 * stripe width and we are allocating past the allocation eof.
+	 */
+	if (mp->m_swidth && (mp->m_flags & XFS_MOUNT_SWALLOC)
+	    && (isize >= XFS_FSB_TO_B(mp, mp->m_swidth)) && aeof) {
+		int eof;
+		xfs_fileoff_t new_last_fsb;
+
+		new_last_fsb = roundup_64(last_fsb, mp->m_swidth);
+		error = xfs_bmap_eof(ip, new_last_fsb, XFS_DATA_FORK, &eof);
+		if (error) {
+			return error;
+		}
+		if (eof) {
+			last_fsb = new_last_fsb;
+		}
 	/*
 	 * Roundup the allocation request to a stripe unit (m_dalign) boundary
 	 * if the file size is >= stripe unit size, and we are allocating past
 	 * the allocation eof.
 	 */
-	if (mp->m_dalign && (isize >= XFS_FSB_TO_B(mp, mp->m_dalign)) && aeof) {
+	} else if (mp->m_dalign && (isize >= XFS_FSB_TO_B(mp, mp->m_dalign))
+		   && aeof) {
 		int eof;
 		xfs_fileoff_t new_last_fsb;
 		new_last_fsb = roundup_64(last_fsb, mp->m_dalign);

fs/xfs/xfs_mount.c

@@ -682,14 +682,21 @@ xfs_mountfs(
 					error = XFS_ERROR(EINVAL);
 					goto error1;
 				}
+				xfs_fs_cmn_err(CE_WARN, mp,
+"stripe alignment turned off: sunit(%d)/swidth(%d) incompatible with agsize(%d)",
+					mp->m_dalign, mp->m_swidth,
+					sbp->sb_agblocks);
+
 				mp->m_dalign = 0;
 				mp->m_swidth = 0;
 			} else if (mp->m_dalign) {
 				mp->m_swidth = XFS_BB_TO_FSBT(mp, mp->m_swidth);
 			} else {
 				if (mp->m_flags & XFS_MOUNT_RETERR) {
-					cmn_err(CE_WARN,
-					"XFS: alignment check 3 failed");
+					xfs_fs_cmn_err(CE_WARN, mp,
+"stripe alignment turned off: sunit(%d) less than bsize(%d)",
+                                        	mp->m_dalign,
+						mp->m_blockmask +1);
 					error = XFS_ERROR(EINVAL);
 					goto error1;
 				}

fs/xfs/xfs_mount.h

@@ -416,6 +416,8 @@ typedef struct xfs_mount {
 #define XFS_MOUNT_NOUUID	0x00010000	/* ignore uuid during mount */
 #define XFS_MOUNT_NOLOGFLUSH	0x00020000
 #define XFS_MOUNT_IDELETE	0x00040000	/* delete empty inode clusters*/
+#define XFS_MOUNT_SWALLOC	0x00080000	/* turn on stripe width
+						 * allocation */
 
 /*
  * Default minimum read and write sizes.

fs/xfs/xfs_vfsops.c

@@ -279,6 +279,9 @@ xfs_start_flags(
 	if (ap->flags & XFSMNT_NOALIGN)
 		mp->m_flags |= XFS_MOUNT_NOALIGN;
 
+	if (ap->flags & XFSMNT_SWALLOC)
+		mp->m_flags |= XFS_MOUNT_SWALLOC;
+
 	if (ap->flags & XFSMNT_OSYNCISOSYNC)
 		mp->m_flags |= XFS_MOUNT_OSYNCISOSYNC;
 
@@ -1614,6 +1617,7 @@ xfs_vget(
 #define MNTOPT_WSYNC	"wsync"		/* safe-mode nfs compatible mount */
 #define MNTOPT_INO64	"ino64"		/* force inodes into 64-bit range */
 #define MNTOPT_NOALIGN	"noalign"	/* turn off stripe alignment */
+#define MNTOPT_SWALLOC	"swalloc"	/* turn on stripe width allocation */
 #define MNTOPT_SUNIT	"sunit"		/* data volume stripe unit */
 #define MNTOPT_SWIDTH	"swidth"	/* data volume stripe width */
 #define MNTOPT_NOUUID	"nouuid"	/* ignore filesystem UUID */
@@ -1721,6 +1725,8 @@ xfs_parseargs(
 #endif
 		} else if (!strcmp(this_char, MNTOPT_NOALIGN)) {
 			args->flags |= XFSMNT_NOALIGN;
+		} else if (!strcmp(this_char, MNTOPT_SWALLOC)) {
+			args->flags |= XFSMNT_SWALLOC;
 		} else if (!strcmp(this_char, MNTOPT_SUNIT)) {
 			if (!value || !*value) {
 				printk("XFS: %s option requires an argument\n",
@@ -1815,6 +1821,7 @@ xfs_showargs(
 		{ XFS_MOUNT_WSYNC,		"," MNTOPT_WSYNC },
 		{ XFS_MOUNT_INO64,		"," MNTOPT_INO64 },
 		{ XFS_MOUNT_NOALIGN,		"," MNTOPT_NOALIGN },
+		{ XFS_MOUNT_SWALLOC,		"," MNTOPT_SWALLOC },
 		{ XFS_MOUNT_NOUUID,		"," MNTOPT_NOUUID },
 		{ XFS_MOUNT_NORECOVERY,		"," MNTOPT_NORECOVERY },
 		{ XFS_MOUNT_OSYNCISOSYNC,	"," MNTOPT_OSYNCISOSYNC },