1 files changed, 37 insertions, 20 deletions

diff --git a/fs/xfs/xfs_fsmap.c b/fs/xfs/xfs_fsmap.c
index d082143feb5a..01c0933a4d10 100644
--- a/fs/xfs/xfs_fsmap.c
+++ b/fs/xfs/xfs_fsmap.c
@@ -26,7 +26,7 @@
 #include "xfs_rtalloc.h"
 
 /* Convert an xfs_fsmap to an fsmap. */
-void
+static void
 xfs_fsmap_from_internal(
 	struct fsmap		*dest,
 	struct xfs_fsmap	*src)
@@ -154,8 +154,7 @@ xfs_fsmap_owner_from_rmap(
 /* getfsmap query state */
 struct xfs_getfsmap_info {
 	struct xfs_fsmap_head	*head;
-	xfs_fsmap_format_t	formatter;	/* formatting fn */
-	void			*format_arg;	/* format buffer */
+	struct fsmap		*fsmap_recs;	/* mapping records */
 	struct xfs_buf		*agf_bp;	/* AGF, for refcount queries */
 	xfs_daddr_t		next_daddr;	/* next daddr we expect */
 	u64			missing_owner;	/* owner of holes */
@@ -223,6 +222,20 @@ xfs_getfsmap_is_shared(
 	return 0;
 }
 
+static inline void
+xfs_getfsmap_format(
+	struct xfs_mount		*mp,
+	struct xfs_fsmap		*xfm,
+	struct xfs_getfsmap_info	*info)
+{
+	struct fsmap			*rec;
+
+	trace_xfs_getfsmap_mapping(mp, xfm);
+
+	rec = &info->fsmap_recs[info->head->fmh_entries++];
+	xfs_fsmap_from_internal(rec, xfm);
+}
+
 /*
  * Format a reverse mapping for getfsmap, having translated rm_startblock
  * into the appropriate daddr units.
@@ -255,6 +268,9 @@ xfs_getfsmap_helper(
 
 	/* Are we just counting mappings? */
 	if (info->head->fmh_count == 0) {
+		if (info->head->fmh_entries == UINT_MAX)
+			return -ECANCELED;
+
 		if (rec_daddr > info->next_daddr)
 			info->head->fmh_entries++;
 
@@ -284,10 +300,7 @@ xfs_getfsmap_helper(
 		fmr.fmr_offset = 0;
 		fmr.fmr_length = rec_daddr - info->next_daddr;
 		fmr.fmr_flags = FMR_OF_SPECIAL_OWNER;
-		error = info->formatter(&fmr, info->format_arg);
-		if (error)
-			return error;
-		info->head->fmh_entries++;
+		xfs_getfsmap_format(mp, &fmr, info);
 	}
 
 	if (info->last)
@@ -319,11 +332,8 @@ xfs_getfsmap_helper(
 		if (shared)
 			fmr.fmr_flags |= FMR_OF_SHARED;
 	}
-	error = info->formatter(&fmr, info->format_arg);
-	if (error)
-		return error;
-	info->head->fmh_entries++;
 
+	xfs_getfsmap_format(mp, &fmr, info);
 out:
 	rec_daddr += XFS_FSB_TO_BB(mp, rec->rm_blockcount);
 	if (info->next_daddr < rec_daddr)
@@ -791,11 +801,11 @@ xfs_getfsmap_check_keys(
 #endif /* CONFIG_XFS_RT */
 
 /*
- * Get filesystem's extents as described in head, and format for
- * output.  Calls formatter to fill the user's buffer until all
- * extents are mapped, until the passed-in head->fmh_count slots have
- * been filled, or until the formatter short-circuits the loop, if it
- * is tracking filled-in extents on its own.
+ * Get filesystem's extents as described in head, and format for output. Fills
+ * in the supplied records array until there are no more reverse mappings to
+ * return or head.fmh_entries == head.fmh_count.  In the second case, this
+ * function returns -ECANCELED to indicate that more records would have been
+ * returned.
  *
  * Key to Confusion
  * ----------------
@@ -815,8 +825,7 @@ int
 xfs_getfsmap(
 	struct xfs_mount		*mp,
 	struct xfs_fsmap_head		*head,
-	xfs_fsmap_format_t		formatter,
-	void				*arg)
+	struct fsmap			*fsmap_recs)
 {
 	struct xfs_trans		*tp = NULL;
 	struct xfs_fsmap		dkeys[2];	/* per-dev keys */
@@ -891,10 +900,17 @@ xfs_getfsmap(
 
 	info.next_daddr = head->fmh_keys[0].fmr_physical +
 			  head->fmh_keys[0].fmr_length;
-	info.formatter = formatter;
-	info.format_arg = arg;
+	info.fsmap_recs = fsmap_recs;
 	info.head = head;
 
+	/*
+	 * If fsmap runs concurrently with a scrub, the freeze can be delayed
+	 * indefinitely as we walk the rmapbt and iterate over metadata
+	 * buffers.  Freeze quiesces the log (which waits for the buffer LRU to
+	 * be emptied) and that won't happen while we're reading buffers.
+	 */
+	sb_start_write(mp->m_super);
+
 	/* For each device we support... */
 	for (i = 0; i < XFS_GETFSMAP_DEVS; i++) {
 		/* Is this device within the range the user asked for? */
@@ -934,6 +950,7 @@ xfs_getfsmap(
 
 	if (tp)
 		xfs_trans_cancel(tp);
+	sb_end_write(mp->m_super);
 	head->fmh_oflags = FMH_OF_DEV_T;
 	return error;
 }