On Thu, 12 Jan 2012 09:51:30 -0200 Carlos Maiolino <[email protected]> wrote:
> During a remount of a cifs filesystem, the mtab file is not properly updated, > which leads to a doubled entry of the same filesystem in the /etc/mtab file. > This patch adds a new function del_mtab() which is called before the > add_mtab() > in case the fs is being remounted. > The del_mtab() function will delete from the mtab, the old entry from the > filesystem which is being remounted, and then, calls add_mtab() to add an > updated entry to the mtab file. > > Signed-off-by: Carlos Maiolino <[email protected]> > --- > mount.cifs.c | 100 > +++++++++++++++++++++++++++++++++++++++++++++++++++++++++- > 1 files changed, 99 insertions(+), 1 deletions(-) > > diff --git a/mount.cifs.c b/mount.cifs.c > index 147f7fc..2f95d35 100644 > --- a/mount.cifs.c > +++ b/mount.cifs.c > @@ -42,6 +42,7 @@ > #include <fcntl.h> > #include <limits.h> > #include <paths.h> > +#include <libgen.h> > #include <sys/mman.h> > #include <sys/wait.h> > #ifdef HAVE_LIBCAP_NG > @@ -161,6 +162,7 @@ > #define OPT_BKUPUID 30 > #define OPT_BKUPGID 31 > > +#define MNT_TMP_FILE "/.mtab.cifs.XXXXXX" > > /* struct for holding parsed mount info for use by privleged process */ > struct parsed_mount_info { > @@ -1624,6 +1626,95 @@ add_mtab_exit: > return rc; > } > > +static int > +del_mtab(char *mountpoint) > +{ > + int tmprc, rc = 0; > + FILE *mnttmp, *mntmtab; > + struct mntent *mountent; > + char *mtabfile, *mtabdir, *mtabtmpfile; > + > + mtabfile = strdup(MOUNTED); > + mtabdir = dirname(mtabfile); > + mtabdir = realloc(mtabdir, strlen(mtabdir) + strlen(MNT_TMP_FILE) + 2); > + if (!mtabdir) { > + fprintf(stderr, "del_mtab: cannot determine current mtab path"); > + rc = EX_FILEIO; > + goto del_mtab_exit; > + } > + > + mtabtmpfile = strcat(mtabdir, MNT_TMP_FILE); > + if (!mtabtmpfile) { > + fprintf(stderr, "del_mtab: cannot allocate memory to tmp file"); > + rc = EX_FILEIO; > + goto del_mtab_exit; > + } > + > + atexit(unlock_mtab); > + rc = lock_mtab(); > + if (rc) { > + fprintf(stderr, "del_mtab: cannot lock mtab"); > + rc = EX_FILEIO; > + goto del_mtab_exit; > + } > + > + mtabtmpfile = mktemp(mtabtmpfile); > + if (!mtabtmpfile) { > + fprintf(stderr, "del_mtab: cannot setup tmp file destination"); > + rc = EX_FILEIO; > + goto del_mtab_exit; > + } > + > + mntmtab = setmntent(MOUNTED, "r"); > + if (!mntmtab) { > + fprintf(stderr, "del_mtab: could not update mount table\n"); > + rc = EX_FILEIO; > + goto del_mtab_exit; > + } > + > + mnttmp = setmntent(mtabtmpfile, "w"); > + if (!mnttmp) { > + fprintf(stderr, "del_mtab: could not update mount table\n"); > + endmntent(mntmtab); > + rc = EX_FILEIO; > + goto del_mtab_exit; > + } > + > + while ((mountent = getmntent(mntmtab)) != NULL) { > + if (!strcmp(mountent->mnt_dir,mountpoint)) > + continue; > + rc = addmntent(mnttmp, mountent); > + if (rc) { > + fprintf(stderr, "del_mtab: unable to add mount entry to > mtab\n"); > + rc = EX_FILEIO; > + goto del_mtab_error; > + } > + } > + > + endmntent(mntmtab); > + > + tmprc = my_endmntent(mnttmp, 0); > + if (tmprc) { > + fprintf(stderr, "del_mtab: error %d detected on close of tmp > file\n", > + tmprc); > + rc = EX_FILEIO; > + goto del_mtab_error; > + } > + > + rename(mtabtmpfile, MOUNTED); > + > +del_mtab_exit: > + unlock_mtab(); > + free(mtabdir); > + return rc; > + > +del_mtab_error: > + if (unlink(mtabtmpfile)) > + fprintf(stderr, "del_mtab: failed to delete tmp file - %s\n", > + strerror(errno)); > + goto del_mtab_exit; > +} > + > /* have the child drop root privileges */ > static int > drop_child_privs(void) > @@ -2021,8 +2112,15 @@ mount_retry: > } > > do_mtab: > - if (!parsed_info->nomtab && !mtab_unusable()) > + if (!parsed_info->nomtab && !mtab_unusable()) { > + if (parsed_info->flags & MS_REMOUNT) { > + rc = del_mtab(mountpoint); > + if (rc) > + goto mount_exit; > + } > + > rc = add_mtab(orig_dev, mountpoint, parsed_info->flags, fstype); > + } > > mount_exit: > if (parsed_info) { Looks good. I'll wait a couple of days before merging it in case anyone else wants to comment, but it should make the next release. Thanks, -- Jeff Layton <[email protected]> -- To unsubscribe from this list: send the line "unsubscribe linux-cifs" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
