# rm -f a; touch a; filefrag a
/boot/a: 0 extents found
works properly, but
# rm -f a; touch a; filefrag -v a
Filesystem type is: ef53
Filesystem cylinder groups is approximately 61
File size of a is 0 (0 blocks, blocksize 1024)
ext logical physical expected length flags
a: 1 extent found
yields 1 extent when it should be 0.
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; clarify this with a comment.
Addresses-redhat-bugzilla: 653234
Signed-off-by: Eric Sandeen <sandeen@xxxxxxxxxx>
diff --git a/misc/filefrag.c b/misc/filefrag.c
index d604b6c..2795e15 100644
--- a/misc/filefrag.c
+++ b/misc/filefrag.c
@@ -180,6 +180,10 @@ static int filefrag_fiemap(int fd, int blk_shift, int *num_extents)
memset(fiemap, 0, sizeof(struct fiemap));
+ /*
+ * If count (and therefore fm_extent_count) == 0, FIEMAP
+ * returns count of extents found without filling in details.
+ */
if (!verbose)
count = 0;
@@ -204,6 +208,14 @@ 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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