* Use '--no-canonicalize' option of mount(8) (available in

util-linux-ng version 2.17 or greater) to avoid calling
readling(2) on the newly mounted filesystem before the mount
procedure is finished.  This has caused a deadlock if audit was
enabled in the kernel.  Also use '--no-canonicalize' for umount to
avoid touching the mounted filesystem.

diff --git a/ChangeLog b/ChangeLog
index 1711026fbce13b32356dbac22593f2f540e62b0e..47e61004b07a2b5b1517993f337f0fe283293fb1 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,12 @@
+2009-12-17  Miklos Szeredi <miklos@szeredi.hu>
+
+       * Use '--no-canonicalize' option of mount(8) (available in
+       util-linux-ng version 2.17 or greater) to avoid calling
+       readling(2) on the newly mounted filesystem before the mount
+       procedure is finished.  This has caused a deadlock if "audit" was
+       enabled in the kernel.  Also use '--no-canonicalize' for umount to
+       avoid touching the mounted filesystem.
+
 2009-09-11  Miklos Szeredi <miklos@szeredi.hu>
 
        * Released 2.8.1

diff --git a/lib/mount_util.c b/lib/mount_util.c
index e78b4820ff38537b6c708270e7ddfa3851778646..3b6e77137577854a434e88e87812641b4aebaf49 100644 (file)
--- a/lib/mount_util.c
+++ b/lib/mount_util.c
@@ -13,6 +13,7 @@
 #include <string.h>
 #include <dirent.h>
 #include <errno.h>
+#include <fcntl.h>
 #include <limits.h>
 #include <mntent.h>
 #include <sys/stat.h>
@@ -53,17 +54,14 @@ static int mtab_needs_update(const char *mnt)
        return 1;
 }
 
-int fuse_mnt_add_mount(const char *progname, const char *fsname,
-                      const char *mnt, const char *type, const char *opts)
+static int add_mount_legacy(const char *progname, const char *fsname,
+                           const char *mnt, const char *type, const char *opts)
 {
        int res;
        int status;
        sigset_t blockmask;
        sigset_t oldmask;
 
-       if (!mtab_needs_update(mnt))
-               return 0;
-
        sigemptyset(&blockmask);
        sigaddset(&blockmask, SIGCHLD);
        res = sigprocmask(SIG_BLOCK, &blockmask, &oldmask);
@@ -116,23 +114,83 @@ int fuse_mnt_add_mount(const char *progname, const char *fsname,
 
  out_restore:
        sigprocmask(SIG_SETMASK, &oldmask, NULL);
+
        return res;
 }
 
-int fuse_mnt_umount(const char *progname, const char *mnt, int lazy)
+static int add_mount(const char *progname, const char *fsname,
+                      const char *mnt, const char *type, const char *opts)
 {
        int res;
        int status;
        sigset_t blockmask;
        sigset_t oldmask;
 
-       if (!mtab_needs_update(mnt)) {
-               res = umount2(mnt, lazy ? 2 : 0);
-               if (res == -1)
-                       fprintf(stderr, "%s: failed to unmount %s: %s\n",
-                               progname, mnt, strerror(errno));
-               return res;
+       sigemptyset(&blockmask);
+       sigaddset(&blockmask, SIGCHLD);
+       res = sigprocmask(SIG_BLOCK, &blockmask, &oldmask);
+       if (res == -1) {
+               fprintf(stderr, "%s: sigprocmask: %s\n", progname, strerror(errno));
+               return -1;
+       }
+
+       res = fork();
+       if (res == -1) {
+               fprintf(stderr, "%s: fork: %s\n", progname, strerror(errno));
+               goto out_restore;
        }
+       if (res == 0) {
+               /*
+                * Hide output, because old versions don't support
+                * --no-canonicalize
+                */
+               int fd = open("/dev/null", O_RDONLY);
+               dup2(fd, 1);
+               dup2(fd, 2);
+
+               sigprocmask(SIG_SETMASK, &oldmask, NULL);
+               setuid(geteuid());
+               execl("/bin/mount", "/bin/mount", "--no-canonicalize", "-i",
+                     "-f", "-t", type, "-o", opts, fsname, mnt, NULL);
+               fprintf(stderr, "%s: failed to execute /bin/mount: %s\n",
+                       progname, strerror(errno));
+               exit(1);
+       }
+       res = waitpid(res, &status, 0);
+       if (res == -1)
+               fprintf(stderr, "%s: waitpid: %s\n", progname, strerror(errno));
+
+       if (status != 0)
+               res = -1;
+
+ out_restore:
+       sigprocmask(SIG_SETMASK, &oldmask, NULL);
+
+       return res;
+}
+
+int fuse_mnt_add_mount(const char *progname, const char *fsname,
+                      const char *mnt, const char *type, const char *opts)
+{
+       int res;
+
+       if (!mtab_needs_update(mnt))
+               return 0;
+
+       res = add_mount(progname, fsname, mnt, type, opts);
+       if (res == -1)
+               res = add_mount_legacy(progname, fsname, mnt, type, opts);
+
+       return res;
+}
+
+static int exec_umount(const char *progname, const char *mnt, int lazy,
+                      int legacy)
+{
+       int res;
+       int status;
+       sigset_t blockmask;
+       sigset_t oldmask;
 
        sigemptyset(&blockmask);
        sigaddset(&blockmask, SIGCHLD);
@@ -148,10 +206,25 @@ int fuse_mnt_umount(const char *progname, const char *mnt, int lazy)
                goto out_restore;
        }
        if (res == 0) {
+               /*
+                * Hide output, because old versions don't support
+                * --no-canonicalize
+                */
+               if (!legacy) {
+                       int fd = open("/dev/null", O_RDONLY);
+                       dup2(fd, 1);
+                       dup2(fd, 2);
+               }
+
                sigprocmask(SIG_SETMASK, &oldmask, NULL);
                setuid(geteuid());
-               execl("/bin/umount", "/bin/umount", "-i", mnt,
-                     lazy ? "-l" : NULL, NULL);
+               if (legacy) {
+                       execl("/bin/umount", "/bin/umount", "-i", mnt,
+                             lazy ? "-l" : NULL, NULL);
+               } else {
+                       execl("/bin/umount", "/bin/umount", "--no-canonicalize",
+                             "-i", mnt, lazy ? "-l" : NULL, NULL);
+               }
                fprintf(stderr, "%s: failed to execute /bin/umount: %s\n",
                        progname, strerror(errno));
                exit(1);
@@ -166,6 +239,26 @@ int fuse_mnt_umount(const char *progname, const char *mnt, int lazy)
  out_restore:
        sigprocmask(SIG_SETMASK, &oldmask, NULL);
        return res;
+
+}
+
+int fuse_mnt_umount(const char *progname, const char *mnt, int lazy)
+{
+       int res;
+
+       if (!mtab_needs_update(mnt)) {
+               res = umount2(mnt, lazy ? 2 : 0);
+               if (res == -1)
+                       fprintf(stderr, "%s: failed to unmount %s: %s\n",
+                               progname, mnt, strerror(errno));
+               return res;
+       }
+
+       res = exec_umount(progname, mnt, lazy, 0);
+       if (res == -1)
+               res = exec_umount(progname, mnt, lazy, 1);
+
+       return res;
 }
 
 char *fuse_mnt_resolve_path(const char *progname, const char *orig)