[dm-devel] [PATCH] kpartx: free loop device after listing partitions

[dm-devel] [PATCH] kpartx: free loop device after listing partitions

[Benjamin Marzinski]

If "kpartx -l" is run on a file that doesn't already have a loop device
associated with it, it will create a loop device to run the command.
Starting with da59d15c6 ("Fix loopback file with kpartx -av"), it will
not free the loop device when exitting. This is because it checks if the
the file it stat()ed is a regular file, before freeing the loop device.
However, after da59d15c6, stat() is rerun on the loop device itself, so
the check fails.  There is no need to check this, if loopcreated is
true, then the file will be a kpartx created loop device, and should be
freed.

Also, keep kpartx from printing that the loop device has been removed
at normal verbosity.

Fixes: da59d15c6 ("Fix loopback file with kpartx -av")
Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>
---
 kpartx/kpartx.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/kpartx/kpartx.c b/kpartx/kpartx.c
index 6a7933fa..8ff116b8 100644
--- a/kpartx/kpartx.c
+++ b/kpartx/kpartx.c
@@ -424,7 +424,7 @@ main(int argc, char **argv){
 					fprintf(stderr, "can't del loop : %s\n",
 					       loopdev);
 				r = 1;
-			} else
+			} else if (verbose)
 				fprintf(stderr, "loop deleted : %s\n", loopdev);
 		}
 		goto end;
@@ -668,16 +668,17 @@ main(int argc, char **argv){
 		if (n > 0)
 			break;
 	}
-	if (what == LIST && loopcreated && S_ISREG (buf.st_mode)) {
+	if (what == LIST && loopcreated) {
 		if (fd != -1)
 			close(fd);
 		if (del_loop(device)) {
 			if (verbose)
-				printf("can't del loop : %s\n",
+				fprintf(stderr, "can't del loop : %s\n",
 					device);
 			exit(1);
 		}
-		printf("loop deleted : %s\n", device);
+		if (verbose)
+			fprintf(stderr, "loop deleted : %s\n", device);
 	}
 
 end:
-- 
2.17.2

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Re: [dm-devel] [PATCH] kpartx: free loop device after listing partitions

[Martin Wilck]

On Wed, 2021-02-24 at 00:05 -0600, Benjamin Marzinski wrote:
> If "kpartx -l" is run on a file that doesn't already have a loop
> device
> associated with it, it will create a loop device to run the command.
> Starting with da59d15c6 ("Fix loopback file with kpartx -av"), it
> will
> not free the loop device when exitting. This is because it checks if
> the
> the file it stat()ed is a regular file, before freeing the loop
> device.
> However, after da59d15c6, stat() is rerun on the loop device itself,
> so
> the check fails.  There is no need to check this, if loopcreated is
> true, then the file will be a kpartx created loop device, and should
> be
> freed.
> 
> Also, keep kpartx from printing that the loop device has been removed
> at normal verbosity.
> 
> Fixes: da59d15c6 ("Fix loopback file with kpartx -av")
> Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>

Reviewed-by: Martin Wilck <mwilck@suse.com>


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