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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 <mkoenig@suse.de>
Signed-off-by: Karel Zak <kzak@redhat.com>
This commit is contained in:
Karel Zak 2008-07-02 14:26:51 +02:00
parent 4ba66edf82
commit e84feaecfd
3 changed files with 34 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

23
mount/lomount.c
View File

@ -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)
{

1
mount/lomount.h
View File

@ -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);

12
mount/umount.c
View File

@ -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: