From d0002e4aefc717a1ed5493c57782da56d9ffe236 Mon Sep 17 00:00:00 2001 From: Karel Zak Date: Wed, 2 Jul 2008 14:26:51 +0200 Subject: [PATCH] umount: improve "-d" option for autoclear loops The new loop auto-destruct feature detaches automatically loop devices when no longer used. This means they are detached with the umount() call. But when we call umount with -d, del_loop() is called and fails because the ioctl() returns ENXIO. We have to check for autoclear loop devices rather than blindly call del_loop(). Reported-by: Matthias Koenig Signed-off-by: Karel Zak --- mount/lomount.c | 23 +++++++++++++++++++++++ mount/lomount.h | 1 + mount/umount.c | 12 ++++++++++-- 3 files changed, 34 insertions(+), 2 deletions(-) diff --git a/mount/lomount.c b/mount/lomount.c index c3ac68a7..79370524 100644 --- a/mount/lomount.c +++ b/mount/lomount.c @@ -102,6 +102,29 @@ is_loop_used(int fd) return ioctl (fd, LOOP_GET_STATUS, &li) == 0; } +int +is_loop_autoclear(const char *device) +{ + struct loop_info lo; + struct loop_info64 lo64; + int fd, rc = 0; + + if ((fd = open(device, O_RDONLY)) < 0) + return 0; + + if (ioctl(fd, LOOP_GET_STATUS64, &lo64) == 0) { + if (lo64.lo_flags & LO_FLAGS_AUTOCLEAR) + rc = 1; + + } else if (ioctl(fd, LOOP_GET_STATUS, &lo) == 0) { + if (lo.lo_flags & LO_FLAGS_AUTOCLEAR) + rc = 1; + } + + close(fd); + return rc; +} + static char * looplist_mk_devname(struct looplist *ll, int num) { diff --git a/mount/lomount.h b/mount/lomount.h index f332a70d..59108d40 100644 --- a/mount/lomount.h +++ b/mount/lomount.h @@ -2,6 +2,7 @@ extern int set_loop(const char *, const char *, unsigned long long, unsigned lon const char *, int, int *); extern int del_loop(const char *); extern int is_loop_device(const char *); +extern int is_loop_autoclear(const char *device); extern char * find_unused_loop_device(void); extern int loopfile_used_with(char *devname, const char *filename, unsigned long long offset); diff --git a/mount/umount.c b/mount/umount.c index 65c8622b..b2bbdae3 100644 --- a/mount/umount.c +++ b/mount/umount.c @@ -190,6 +190,7 @@ umount_one (const char *spec, const char *node, const char *type, int res; int status; const char *loopdev; + int myloop = 0; /* Special case for root. As of 0.99pl10 we can (almost) unmount root; the kernel will remount it readonly so that we can carry on running @@ -201,7 +202,7 @@ umount_one (const char *spec, const char *node, const char *type, || streq (node, "rootfs")); if (isroot) nomtab++; - + /* * Call umount.TYPE for types that require a separate umount program. * All such special things must occur isolated in the types string. @@ -209,6 +210,13 @@ umount_one (const char *spec, const char *node, const char *type, if (check_special_umountprog(spec, node, type, &status)) return status; + /* + * Ignore the option "-d" for non-loop devices and loop devices with + * LO_FLAGS_AUTOCLEAR flag. + */ + if (delloop && is_loop_device(spec) && !is_loop_autoclear(spec)) + myloop = 1; + umnt_err = umnt_err2 = 0; if (lazy) { res = umount2 (node, MNT_DETACH); @@ -310,7 +318,7 @@ umount_one (const char *spec, const char *node, const char *type, } /* Also free loop devices when -d flag is given */ - if (delloop && is_loop_device(spec)) + if (myloop) loopdev = spec; } gotloop: -- 2.39.5