Merge branch 'for-linus' of git://oss.sgi.com/xfs/xfs

* 'for-linus' of git://oss.sgi.com/xfs/xfs:
  xfs: correctly decrement the extent buffer index in xfs_bmap_del_extent
  xfs: check for valid indices in xfs_iext_get_ext and xfs_iext_idx_to_irec
  xfs: fix up asserts in xfs_iflush_fork
  xfs: do not do pointer arithmetic on extent records
  xfs: do not use unchecked extent indices in xfs_bunmapi
  xfs: do not use unchecked extent indices in xfs_bmapi
  xfs: do not use unchecked extent indices in xfs_bmap_add_extent_*
  xfs: remove if_lastex
  xfs: remove the unused XFS_BMAPI_RSVBLOCKS flag
  xfs: do not discard alloc btree blocks
  xfs: add online discard support

Documentation/filesystems/xfs.txt

@@ -39,6 +39,12 @@ When mounting an XFS filesystem, the following options are accepted.
 	drive level write caching to be enabled, for devices that
 	support write barriers.
 
+  discard
+	Issue command to let the block device reclaim space freed by the
+	filesystem.  This is useful for SSD devices, thinly provisioned
+	LUNs and virtual machine images, but may have a performance
+	impact.  This option is incompatible with the nodelaylog option.
+
   dmapi
 	Enable the DMAPI (Data Management API) event callouts.
 	Use with the "mtpt" option.

fs/xfs/linux-2.6/xfs_discard.c

@@ -191,3 +191,32 @@ xfs_ioc_trim(
 		return -XFS_ERROR(EFAULT);
 	return 0;
 }
+
+int
+xfs_discard_extents(
+	struct xfs_mount	*mp,
+	struct list_head	*list)
+{
+	struct xfs_busy_extent	*busyp;
+	int			error = 0;
+
+	list_for_each_entry(busyp, list, list) {
+		trace_xfs_discard_extent(mp, busyp->agno, busyp->bno,
+					 busyp->length);
+
+		error = -blkdev_issue_discard(mp->m_ddev_targp->bt_bdev,
+				XFS_AGB_TO_DADDR(mp, busyp->agno, busyp->bno),
+				XFS_FSB_TO_BB(mp, busyp->length),
+				GFP_NOFS, 0);
+		if (error && error != EOPNOTSUPP) {
+			xfs_info(mp,
+	 "discard failed for extent [0x%llu,%u], error %d",
+				 (unsigned long long)busyp->bno,
+				 busyp->length,
+				 error);
+			return error;
+		}
+	}
+
+	return 0;
+}

fs/xfs/linux-2.6/xfs_discard.h

@@ -2,7 +2,9 @@
 #define XFS_DISCARD_H 1
 
 struct fstrim_range;
+struct list_head;
 
 extern int	xfs_ioc_trim(struct xfs_mount *, struct fstrim_range __user *);
+extern int	xfs_discard_extents(struct xfs_mount *, struct list_head *);
 
 #endif /* XFS_DISCARD_H */

fs/xfs/linux-2.6/xfs_super.c

@@ -110,8 +110,10 @@ mempool_t *xfs_ioend_pool;
 #define MNTOPT_GQUOTANOENF "gqnoenforce"/* group quota limit enforcement */
 #define MNTOPT_PQUOTANOENF "pqnoenforce"/* project quota limit enforcement */
 #define MNTOPT_QUOTANOENF  "qnoenforce"	/* same as uqnoenforce */
-#define MNTOPT_DELAYLOG   "delaylog"	/* Delayed loging enabled */
-#define MNTOPT_NODELAYLOG "nodelaylog"	/* Delayed loging disabled */
+#define MNTOPT_DELAYLOG    "delaylog"	/* Delayed logging enabled */
+#define MNTOPT_NODELAYLOG  "nodelaylog"	/* Delayed logging disabled */
+#define MNTOPT_DISCARD	   "discard"	/* Discard unused blocks */
+#define MNTOPT_NODISCARD   "nodiscard"	/* Do not discard unused blocks */
 
 /*
  * Table driven mount option parser.
@@ -355,6 +357,10 @@ xfs_parseargs(
 			mp->m_flags |= XFS_MOUNT_DELAYLOG;
 		} else if (!strcmp(this_char, MNTOPT_NODELAYLOG)) {
 			mp->m_flags &= ~XFS_MOUNT_DELAYLOG;
+		} else if (!strcmp(this_char, MNTOPT_DISCARD)) {
+			mp->m_flags |= XFS_MOUNT_DISCARD;
+		} else if (!strcmp(this_char, MNTOPT_NODISCARD)) {
+			mp->m_flags &= ~XFS_MOUNT_DISCARD;
 		} else if (!strcmp(this_char, "ihashsize")) {
 			xfs_warn(mp,
 	"ihashsize no longer used, option is deprecated.");
@@ -388,6 +394,13 @@ xfs_parseargs(
 		return EINVAL;
 	}
 
+	if ((mp->m_flags & XFS_MOUNT_DISCARD) &&
+	    !(mp->m_flags & XFS_MOUNT_DELAYLOG)) {
+		xfs_warn(mp,
+	"the discard option is incompatible with the nodelaylog option");
+		return EINVAL;
+	}
+
 #ifndef CONFIG_XFS_QUOTA
 	if (XFS_IS_QUOTA_RUNNING(mp)) {
 		xfs_warn(mp, "quota support not available in this kernel.");
@@ -488,6 +501,7 @@ xfs_showargs(
 		{ XFS_MOUNT_FILESTREAMS,	"," MNTOPT_FILESTREAM },
 		{ XFS_MOUNT_GRPID,		"," MNTOPT_GRPID },
 		{ XFS_MOUNT_DELAYLOG,		"," MNTOPT_DELAYLOG },
+		{ XFS_MOUNT_DISCARD,		"," MNTOPT_DISCARD },
 		{ 0, NULL }
 	};
 	static struct proc_xfs_info xfs_info_unset[] = {

fs/xfs/xfs_ag.h

@@ -187,6 +187,9 @@ struct xfs_busy_extent {
 	xfs_agnumber_t	agno;
 	xfs_agblock_t	bno;
 	xfs_extlen_t	length;
+	unsigned int	flags;
+#define XFS_ALLOC_BUSY_DISCARDED	0x01	/* undergoing a discard op. */
+#define XFS_ALLOC_BUSY_SKIP_DISCARD	0x02	/* do not discard */
 };
 
 /*

fs/xfs/xfs_alloc.c

@@ -2469,7 +2469,7 @@ xfs_free_extent(
 
 	error = xfs_free_ag_extent(tp, args.agbp, args.agno, args.agbno, len, 0);
 	if (!error)
-		xfs_alloc_busy_insert(tp, args.agno, args.agbno, len);
+		xfs_alloc_busy_insert(tp, args.agno, args.agbno, len, 0);
 error0:
 	xfs_perag_put(args.pag);
 	return error;
@@ -2480,7 +2480,8 @@ xfs_alloc_busy_insert(
 	struct xfs_trans	*tp,
 	xfs_agnumber_t		agno,
 	xfs_agblock_t		bno,
-	xfs_extlen_t		len)
+	xfs_extlen_t		len,
+	unsigned int		flags)
 {
 	struct xfs_busy_extent	*new;
 	struct xfs_busy_extent	*busyp;
@@ -2504,6 +2505,7 @@ xfs_alloc_busy_insert(
 	new->bno = bno;
 	new->length = len;
 	INIT_LIST_HEAD(&new->list);
+	new->flags = flags;
 
 	/* trace before insert to be able to see failed inserts */
 	trace_xfs_alloc_busy(tp->t_mountp, agno, bno, len);
@@ -2608,6 +2610,18 @@ xfs_alloc_busy_update_extent(
 	xfs_agblock_t		bbno = busyp->bno;
 	xfs_agblock_t		bend = bbno + busyp->length;
 
+	/*
+	 * This extent is currently being discarded.  Give the thread
+	 * performing the discard a chance to mark the extent unbusy
+	 * and retry.
+	 */
+	if (busyp->flags & XFS_ALLOC_BUSY_DISCARDED) {
+		spin_unlock(&pag->pagb_lock);
+		delay(1);
+		spin_lock(&pag->pagb_lock);
+		return false;
+	}
+
 	/*
 	 * If there is a busy extent overlapping a user allocation, we have
 	 * no choice but to force the log and retry the search.
@@ -2813,7 +2827,8 @@ xfs_alloc_busy_trim(
 		 * If this is a metadata allocation, try to reuse the busy
 		 * extent instead of trimming the allocation.
 		 */
-		if (!args->userdata) {
+		if (!args->userdata &&
+		    !(busyp->flags & XFS_ALLOC_BUSY_DISCARDED)) {
 			if (!xfs_alloc_busy_update_extent(args->mp, args->pag,
 							  busyp, fbno, flen,
 							  false))
@@ -2979,10 +2994,16 @@ xfs_alloc_busy_clear_one(
 	kmem_free(busyp);
 }
 
+/*
+ * Remove all extents on the passed in list from the busy extents tree.
+ * If do_discard is set skip extents that need to be discarded, and mark
+ * these as undergoing a discard operation instead.
+ */
 void
 xfs_alloc_busy_clear(
 	struct xfs_mount	*mp,
-	struct list_head	*list)
+	struct list_head	*list,
+	bool			do_discard)
 {
 	struct xfs_busy_extent	*busyp, *n;
 	struct xfs_perag	*pag = NULL;
@@ -2999,7 +3020,11 @@ xfs_alloc_busy_clear(
 			agno = busyp->agno;
 		}
 
-		xfs_alloc_busy_clear_one(mp, pag, busyp);
+		if (do_discard && busyp->length &&
+		    !(busyp->flags & XFS_ALLOC_BUSY_SKIP_DISCARD))
+			busyp->flags = XFS_ALLOC_BUSY_DISCARDED;
+		else
+			xfs_alloc_busy_clear_one(mp, pag, busyp);
 	}
 
 	if (pag) {

fs/xfs/xfs_alloc.h

@@ -137,10 +137,11 @@ xfs_alloc_longest_free_extent(struct xfs_mount *mp,
 #ifdef __KERNEL__
 void
 xfs_alloc_busy_insert(struct xfs_trans *tp, xfs_agnumber_t agno,
-	xfs_agblock_t bno, xfs_extlen_t len);
+	xfs_agblock_t bno, xfs_extlen_t len, unsigned int flags);
 
 void
-xfs_alloc_busy_clear(struct xfs_mount *mp, struct list_head *list);
+xfs_alloc_busy_clear(struct xfs_mount *mp, struct list_head *list,
+	bool do_discard);
 
 int
 xfs_alloc_busy_search(struct xfs_mount *mp, xfs_agnumber_t agno,

fs/xfs/xfs_alloc_btree.c

@@ -120,7 +120,8 @@ xfs_allocbt_free_block(
 	if (error)
 		return error;
 
-	xfs_alloc_busy_insert(cur->bc_tp, be32_to_cpu(agf->agf_seqno), bno, 1);
+	xfs_alloc_busy_insert(cur->bc_tp, be32_to_cpu(agf->agf_seqno), bno, 1,
+			      XFS_ALLOC_BUSY_SKIP_DISCARD);
 	xfs_trans_agbtree_delta(cur->bc_tp, -1);
 	return 0;
 }