From 56ee5765074b2f2389066f3234a4da21501d3eaa Mon Sep 17 00:00:00 2001 From: Denys Vlasenko Date: Wed, 9 Dec 2020 20:56:43 +0100 Subject: mount: fix incorrect "success" exitcode if loop device setup fails When mounting, in parallel, multiple loop devices (squashfs for the submitter's case), the following behavior can be observed: stat64(/path/to/image, {st_mode=S_IFREG|0644, st_size=4096, ...}) = 0 openat(AT_FDCWD, /path/to/image, O_RDWR|O_LARGEFILE) = 3 openat(AT_FDCWD, /dev/loop-control, O_RDWR|O_LARGEFILE|O_CLOEXEC) = 4 ioctl(4, LOOP_CTL_GET_FREE) = 12 close(4) = 0 openat(AT_FDCWD, /dev/loop12, O_RDWR|O_LARGEFILE) = 4 ioctl(4, LOOP_GET_STATUS64, {lo_offset=0, lo_number=12, lo_flags=LO_FLAGS_AUTOCLEAR, lo_file_name=/path/to/image, ...}) = 0 close(4) = 0 close(3) = 0 write(2, "mount: can't setup loop device\n", 31mount: can't setup loop device ) = 31 exit_group(0) = ? +++ exited with 0 +++ The ioctl LOOP_CTL_GET_FREE has resulted in the same result for a competing mount process. The subsequent ioctl LOOP_GET_STATUS64 fails, having succeeded for the competing mount process. Signed-off-by: Denys Vlasenko --- util-linux/mount.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'util-linux') diff --git a/util-linux/mount.c b/util-linux/mount.c index 2eadee88b..0814a5256 100644 --- a/util-linux/mount.c +++ b/util-linux/mount.c @@ -2078,8 +2078,8 @@ static int singlemount(struct mntent *mp, int ignore_busy) && (!mp->mnt_type || is_prefixed_with(mp->mnt_type, "nfs")) ) { char *colon = strchr(mp->mnt_fsname, ':'); - if (colon /* looks like "hostname:..." */ - && strchrnul(mp->mnt_fsname, '/') > colon /* "hostname:" has no slashes */ + if (colon // looks like "hostname:..." + && strchrnul(mp->mnt_fsname, '/') > colon // "hostname:" has no slashes ) { if (!mp->mnt_type) mp->mnt_type = (char*)"nfs"; @@ -2125,7 +2125,7 @@ static int singlemount(struct mntent *mp, int ignore_busy) bb_simple_error_msg(bb_msg_perm_denied_are_you_root); else bb_simple_perror_msg("can't setup loop device"); - return errno; + return loopfd; // was "return errno", but it can be 0 here } // Autodetect bind mounts -- cgit v1.2.3