[LTP] [PATCH] lib/rmobj.c: fix warning on FUSE fs

[LTP] [PATCH] lib/rmobj.c: fix warning on FUSE fs

[Alexey Kodanev]

This warning can appear on FUSE fs in cleanup():
TWARN  :  tst_tmpdir.c:219: tst_rmdir: rmobj(...) failed: unlink(
.../.fuse_hidden#####) failed; errno=2: No such file or directory

rmobj recursively goes through directory entries and unlinks files
there. During the time between getting the entry and calling unlink()
the file can be deleted by FS.

We can fix it by skipping ENOENT errno as it is possible that a file
might not exist by that time.

Signed-off-by: Alexey Kodanev <alexey.kodanev@oracle.com>
---
 lib/rmobj.c |    9 +++++++--
 1 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/lib/rmobj.c b/lib/rmobj.c
index a9de59c..aa5bb6a 100644
--- a/lib/rmobj.c
+++ b/lib/rmobj.c
@@ -192,8 +192,13 @@ int rmobj(char *obj, char **errmsg)
 			}
 		}
 	} else {
-		/* object is not a directory; just use unlink() */
-		if (unlink(obj) < 0) {
+		/* object is not a directory; just use unlink()
+		 * Note: skip ENOENT errno as it might catch hidden temporary
+		 * files (e.g. can be created by FUSE FS) when listing directory
+		 * entries on the previous stage, but the file could have been
+		 * removed by FS already.
+		 */
+		if (unlink(obj) < 0 && errno != ENOENT) {
 			if (errmsg != NULL) {
 				sprintf(err_msg,
 					"unlink(%s) failed; errno=%d: %s", obj,
-- 
1.7.1

[LTP] [PATCH] lib/rmobj.c: fix warning on FUSE fs

[Cyril Hrubis]

Hi!
> This warning can appear on FUSE fs in cleanup():
> TWARN  :  tst_tmpdir.c:219: tst_rmdir: rmobj(...) failed: unlink(
> .../.fuse_hidden#####) failed; errno=2: No such file or directory

Isn't this the same problem as the NFS one? I.e. unlinked but still open
files?

But in this case it looks like the file was still there shortly after
the fd has been closed, right? I wonder if that is a bug or not. I would
expect that the file is no longer in the directory listing once the
close() has returned from kernel.

-- 
Cyril Hrubis
chrubis@suse.cz

[LTP] [PATCH] lib/rmobj.c: fix warning on FUSE fs

[Alexey Kodanev]

Hi,
On 04/27/2016 03:15 PM, Cyril Hrubis wrote:
> Hi!
>> This warning can appear on FUSE fs in cleanup():
>> TWARN  :  tst_tmpdir.c:219: tst_rmdir: rmobj(...) failed: unlink(
>> .../.fuse_hidden#####) failed; errno=2: No such file or directory
> Isn't this the same problem as the NFS one? I.e. unlinked but still open
> files?

No, checked syscalls/* tests, they all are closing fds before tst_rmdir().

It happens only if test does unlink(fd), then close(fd). If we change a test
so it calls close(fd) first, then unlink(fd), then ".fuse_hidden" never 
being
created to store data about unlinked but still open file, and we won't have
this warning too. It's just another way to workaround it in the tests.

>
> But in this case it looks like the file was still there shortly after
> the fd has been closed, right? I wonder if that is a bug or not. I would
> expect that the file is no longer in the directory listing once the
> close() has returned from kernel.

Hmm, may be it is a bug, for a short period of time after close() we can
still have this temporary file listed. OK, I will check it with our 
developers.

Thanks,
Alexey