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 | 102 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 files changed, 102 insertions(+), 0 deletions(-) diff --git a/mount.cifs.c b/mount.cifs.c index 147f7fc..d9bf0b9 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.tmp.XXXXXX" /* struct for holding parsed mount info for use by privleged process */ struct parsed_mount_info { @@ -1624,6 +1626,101 @@ add_mtab_exit: return rc; } +static int +del_mtab(char *mountpoint) +{ + int fd, tmprc, rc = 0; + FILE *mnttmp, *mntmtab; + struct mntent *mountent; + struct stat statbuf; + char *mtabfile, *mtabdir, *tmpfile; + + mtabfile = strdup(MOUNTED); + mtabdir = dirname(mtabfile); + if (!mtabdir) { + fprintf(stderr, "del_mtab: cannot determine current mtab path"); + rc = EX_FILEIO; + goto del_mtab_exit; + } + + tmpfile = strcat(mtabdir, MNT_TMP_FILE); + + atexit(unlink(tmpfile)); + tmpfile = mktemp(tmpfile); + if (!tmpfile) { + fprintf(stderr, "del_mtab: cannot setup tmp file destination"); + 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; + } + + 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(tmpfile, "w"); + if (!mnttmp) { + fprintf(stderr, "del_mtab: could not update mount table\n"); + endmntent(mntmtab); + rc = EX_FILEIO; + goto del_mtab_exit; + } + + fd = fileno(mntmtab); + if (fd < 0) { + fprintf(stderr, "del_mtab: mntent does not appear to be valid\n"); + endmntent(mntmtab); + endmntent(mnttmp); + 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"); + ftruncate(fd, statbuf.st_size); + rc = EX_FILEIO; + break; + } + } + + rc = fstat(fd, &statbuf); + if (rc != 0) { + fprintf(stderr, "del_mtab: unable to fstat open mtab\n"); + endmntent(mntmtab); + endmntent(mnttmp); + rc = EX_FILEIO; + goto del_mtab_exit; + } + + tmprc = my_endmntent(mntmtab, statbuf.st_size); + if (tmprc) { + fprintf(stderr, "del_mtab: error %d detected on close of mtab\n", tmprc); + rc = EX_FILEIO; + } + endmntent(mnttmp); + + rename(tmpfile, MOUNTED); + unlink(tmpfile); + +del_mtab_exit: + unlock_mtab(); + return rc; +} + /* have the child drop root privileges */ static int drop_child_privs(void) @@ -2021,6 +2118,11 @@ mount_retry: } do_mtab: + if (parsed_info->flags & MS_REMOUNT){ + rc = del_mtab(mountpoint); + if (rc) + goto mount_exit; + } if (!parsed_info->nomtab && !mtab_unusable()) rc = add_mtab(orig_dev, mountpoint, parsed_info->flags, fstype); -- 1.7.6.4 -- 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
