From: Dave Chinner <dchinner@redhat.com>
Date: Fri, 2 Mar 2012 08:34:58 +0000 (+0000)
Subject: xfs_io: fix fiemap loop continuation
X-Git-Tag: v3.1.8~10
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=ef45fa5e892a8f267c24f0e244082c36102d9347;p=thirdparty%2Fxfsprogs-dev.git

xfs_io: fix fiemap loop continuation

When the fiemap command needs to retrieve more extents from the
kernel via a subsequent IO, it calculates the next logical block to
retrieve in file system block units. the fiemap needs the start
offset in bytes, not filesystem blocks.  Hence if the fiemap command
can loop forever retrieving the same blocks if the logical offset
offset of the next block in filesystem block units is smaller than
the number of bytes in a filessytem block. i.e. it will just loop
retreiving the first 32 extents from offset block zero.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
---

diff --git a/io/fiemap.c b/io/fiemap.c
index 99296ddba..e32a41668 100644
--- a/io/fiemap.c
+++ b/io/fiemap.c
@@ -75,12 +75,14 @@ print_verbose(
 	__u64			*last_logical)
 {
 	__u64			lstart;
+	__u64			llast;
 	__u64			len;
 	__u64			block;
 	char			lbuf[48];
 	char			bbuf[48];
 	char			flgbuf[16];
 
+	llast = *last_logical / blocksize;
 	lstart = extent->fe_logical / blocksize;
 	len = extent->fe_length / blocksize;
 	block = extent->fe_physical / blocksize;
@@ -88,11 +90,11 @@ print_verbose(
 	memset(lbuf, 0, sizeof(lbuf));
 	memset(bbuf, 0, sizeof(bbuf));
 
-	if (lstart != *last_logical) {
-		snprintf(lbuf, sizeof(lbuf), "[%llu..%llu]:", *last_logical,
+	if (lstart != llast) {
+		snprintf(lbuf, sizeof(lbuf), "[%llu..%llu]:", llast,
 			 lstart - 1ULL);
 		printf("%4d: %-*s %-*s %*llu\n", *cur_extent, foff_w, lbuf,
-		       boff_w, _("hole"), tot_w, lstart - *last_logical);
+		       boff_w, _("hole"), tot_w, lstart - llast);
 		(*cur_extent)++;
 		memset(lbuf, 0, sizeof(lbuf));
 	}
@@ -121,19 +123,20 @@ print_plain(
 	__u64			*last_logical)
 {
 	__u64			lstart;
+	__u64			llast;
 	__u64			block;
 	__u64			len;
 
+	llast = *last_logical / blocksize;
 	lstart = extent->fe_logical / blocksize;
 	len = extent->fe_length / blocksize;
 	block = extent->fe_physical / blocksize;
 
-	if (lstart != *last_logical) {
+	if (lstart != llast) {
 		printf("\t%d: [%llu..%llu]: hole", *cur_extent,
-		       *last_logical, lstart - 1ULL);
+		       llast, lstart - 1ULL);
 		if (lflag)
-			printf(_(" %llu blocks\n"),
-			       lstart - *last_logical);
+			printf(_(" %llu blocks\n"), lstart - llast);
 		else
 			printf("\n");
 		(*cur_extent)++;
@@ -281,6 +284,7 @@ fiemap_f(
 				print_plain(extent, lflag, blocksize,
 					    max_extents, &cur_extent,
 					    &last_logical);
+
 			if (extent->fe_flags & FIEMAP_EXTENT_LAST) {
 				last = 1;
 				break;
@@ -303,22 +307,21 @@ fiemap_f(
 		return 0;
 	}
 
-	if (cur_extent && last_logical < (st.st_size / blocksize)) {
+	if (cur_extent && last_logical < st.st_size) {
 		char	lbuf[32];
 
 		snprintf(lbuf, sizeof(lbuf), "[%llu..%llu]:",
-			 last_logical, (st.st_size / blocksize) - 1);
+			 last_logical / blocksize, (st.st_size / blocksize) - 1);
 		if (vflag) {
 			printf("%4d: %-*s %-*s %*llu\n", cur_extent,
 			       foff_w, lbuf, boff_w, _("hole"), tot_w,
-			       (st.st_size / blocksize) - last_logical);
+			       (st.st_size - last_logical) / blocksize);
 		} else {
 			printf("\t%d: %s %s", cur_extent, lbuf,
 			       _("hole"));
 			if (lflag)
 				printf(_(" %llu blocks\n"),
-				       (st.st_size / blocksize) -
-				       last_logical);
+				       (st.st_size - last_logical) / blocksize);
 			else
 				printf("\n");
 		}