# rm -f a; touch a; filefrag -v a
yields 1 extent when it should be 0. Without -v, 0 is returned.
Fix this up by special-casing no extents returned in verbose
mode; skip printing the header for the columns too, since there
are no columns to print.
Also, in nonverbose mode we can set fm_extent_count to 0
so that FIEMAP will just query the extent count without gathering
details; as it is today I think a non-verbose query may under-report
the extent count once "count" extents have been filled in.
Addresses-redhat-bugzilla: 653234
Signed-off-by: Eric Sandeen <sandeen@xxxxxxxxxx>
---
diff --git a/misc/filefrag.c b/misc/filefrag.c
index bd4486d..a48b9b0 100644
--- a/misc/filefrag.c
+++ b/misc/filefrag.c
@@ -194,7 +194,14 @@ static int filefrag_fiemap(int fd, int blk_shift, int *num_extents)
do {
fiemap->fm_length = ~0ULL;
fiemap->fm_flags = flags;
- fiemap->fm_extent_count = count;
+ /*
+ * If fm_extent_count == 0, FIEMAP returns count of
+ * extents found without filling in details.
+ */
+ if (!verbose)
+ fiemap->fm_extent_count = 0;
+ else
+ fiemap->fm_extent_count = count;
rc = ioctl(fd, FS_IOC_FIEMAP, (unsigned long) fiemap);
if (rc < 0) {
if (errno == EBADR && fiemap_incompat_printed == 0) {
@@ -206,6 +213,14 @@ static int filefrag_fiemap(int fd, int blk_shift, int *num_extents)
}
if (verbose && !fiemap_header_printed) {
+ /*
+ * No extents on first call?
+ * Skip header and show 0 extents.
+ */
+ if (fiemap->fm_mapped_extents == 0) {
+ *num_extents = 0;
+ goto out;
+ }
printf(" ext %*s %*s %*s length flags\n", logical_width,
"logical", physical_width, "physical",
physical_width, "expected");
--
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