ismounted.c (check_mntent, check_mntent_file): Add better

	support for loopback-mounted filesystems.  Check /etc/mtab
	if /proc/mounts doesn't turn up any mount flags, since
	/etc/mtab has the loopback image filename, instead of
	/dev/loop0.  Also, check based on st_dev and st_ino, so
	that if a relative pathname or a pathnames using symbolic
	links are used, we can detect the the filesystem correctly
	in those cases.  (Addresses Sourceforge bug #619119)

diff --git a/lib/ext2fs/ChangeLog b/lib/ext2fs/ChangeLog
index d1e4f18..634e43e 100644 (file)
--- a/lib/ext2fs/ChangeLog
+++ b/lib/ext2fs/ChangeLog
@@ -1,5 +1,14 @@
 2002-10-31  Theodore Ts'o  <tytso@mit.edu>
 
+       * ismounted.c (check_mntent, check_mntent_file): Add better
+               support for loopback-mounted filesystems.  Check /etc/mtab
+               if /proc/mounts doesn't turn up any mount flags, since
+               /etc/mtab has the loopback image filename, instead of
+               /dev/loop0.  Also, check based on st_dev and st_ino, so
+               that if a relative pathname or a pathnames using symbolic
+               links are used, we can detect the the filesystem correctly
+               in those cases.  (Addresses Sourceforge bug #619119)
+
        * flushb.c (ext2fs_sync_device): If the BLKFLSBUF ioctl succeeds,
                don't try the FDFLUSH ioctl that was required for floppies
                with older kernels.  This avoids needless whining from the

diff --git a/lib/ext2fs/ismounted.c b/lib/ext2fs/ismounted.c
index 3dcc6f9..3552a1b 100644 (file)
--- a/lib/ext2fs/ismounted.c
+++ b/lib/ext2fs/ismounted.c
@@ -46,28 +46,39 @@ static errcode_t check_mntent_file(const char *mtab_file, const char *file,
        struct mntent   *mnt;
        struct stat     st_buf;
        errcode_t       retval = 0;
-       dev_t           file_dev;
+       dev_t           file_dev=0, file_rdev=0;
+       ino_t           file_ino=0;
        FILE            *f;
        int             fd;
 
        *mount_flags = 0;
        if ((f = setmntent (mtab_file, "r")) == NULL)
                return errno;
-       file_dev = 0;
+       if (stat(file, &st_buf) == 0) {
+               if (S_ISBLK(st_buf.st_mode)) {
 #ifndef __GNU__ /* The GNU hurd is broken with respect to stat devices */
-       if ((stat(file, &st_buf) == 0) &&
-           S_ISBLK(st_buf.st_mode))
-               file_dev = st_buf.st_rdev;
+                       file_rdev = st_buf.st_rdev;
 #endif /* __GNU__ */
+               } else {
+                       file_dev = st_buf.st_dev;
+                       file_ino = st_buf.st_ino;
+               }
+       }
        while ((mnt = getmntent (f)) != NULL) {
                if (strcmp(file, mnt->mnt_fsname) == 0)
                        break;
+               if (stat(mnt->mnt_fsname, &st_buf) == 0) {
+                       if (S_ISBLK(st_buf.st_mode)) {
 #ifndef __GNU__
-               if (file_dev && (stat(mnt->mnt_fsname, &st_buf) == 0) &&
-                   S_ISBLK(st_buf.st_mode) &&
-                   (file_dev == st_buf.st_rdev))
-                       break;
+                               if (file_rdev && (file_rdev == st_buf.st_rdev))
+                                       break;
 #endif /* __GNU__ */
+                       } else {
+                               if (file_dev && ((file_dev == st_buf.st_dev) &&
+                                                (file_ino == st_buf.st_ino)))
+                                       break;
+                       }
+               }
        }
 
        if (mnt == 0) {
@@ -79,8 +90,8 @@ static errcode_t check_mntent_file(const char *mtab_file, const char *file,
                 * check if the given device has the same major/minor number
                 * as the device that the root directory is on.
                 */
-               if (file_dev && stat("/", &st_buf) == 0) {
-                       if (st_buf.st_dev == file_dev) {
+               if (file_rdev && stat("/", &st_buf) == 0) {
+                       if (st_buf.st_dev == file_rdev) {
                                *mount_flags = EXT2_MF_MOUNTED;
                                if (mtpt)
                                        strncpy(mtpt, "/", mtlen);
@@ -108,7 +119,7 @@ static errcode_t check_mntent_file(const char *mtab_file, const char *file,
                }
                goto exit;
        }
-       if (file_dev && (st_buf.st_dev != file_dev)) {
+       if (file_rdev && (st_buf.st_dev != file_rdev)) {
 #ifdef DEBUG
                printf("Bogus entry in %s!  (%s not mounted on %s)\n",
                       mtab_file, file, mnt->mnt_dir);
@@ -162,7 +173,7 @@ static errcode_t check_mntent(const char *file, int *mount_flags,
 #ifdef __linux__
        retval = check_mntent_file("/proc/mounts", file, mount_flags,
                                   mtpt, mtlen);
-       if (retval == 0)
+       if (retval == 0 && (*mount_flags != 0))
                return 0;
 #endif /* __linux__ */
 #if defined(MOUNTED) || defined(_PATH_MOUNTED)