util-linux/util-linux-2.12h-mtablock.diff

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Index: util-linux-2.12r/mount/fstab.c
===================================================================
--- util-linux-2.12r.orig/mount/fstab.c
+++ util-linux-2.12r/mount/fstab.c
@@ -395,6 +395,7 @@ getfsvolspec (const char *label) {
/* Flag for already existing lock file. */
static int we_created_lockfile = 0;
+static int lockfile_fd = -1;
/* Flag to indicate that signals have been set up. */
static int signals_have_been_setup = 0;
@@ -416,6 +417,8 @@ setlkw_timeout (int sig) {
void
unlock_mtab (void) {
if (we_created_lockfile) {
+ close(lockfile_fd);
+ lockfile_fd = -1;
unlink (MOUNTED_LOCK);
we_created_lockfile = 0;
}
@@ -443,7 +446,7 @@ unlock_mtab (void) {
void
lock_mtab (void) {
- int tries = 3;
+ int tries = 100000, i;
char linktargetfile[MOUNTLOCK_LINKTARGET_LTH];
at_die = unlock_mtab;
@@ -469,45 +472,48 @@ lock_mtab (void) {
sprintf(linktargetfile, MOUNTLOCK_LINKTARGET, getpid ());
+ i = open (linktargetfile, O_WRONLY|O_CREAT, 0);
+ if (i < 0) {
+ int errsv = errno;
+ /* linktargetfile does not exist (as a file)
+ and we cannot create it. Read-only filesystem?
+ Too many files open in the system?
+ Filesystem full? */
+ die (EX_FILEIO, _("can't create lock file %s: %s "
+ "(use -n flag to override)"),
+ linktargetfile, strerror (errsv));
+ }
+ close(i);
+
/* Repeat until it was us who made the link */
while (!we_created_lockfile) {
struct flock flock;
- int errsv, fd, i, j;
-
- i = open (linktargetfile, O_WRONLY|O_CREAT, 0);
- if (i < 0) {
- int errsv = errno;
- /* linktargetfile does not exist (as a file)
- and we cannot create it. Read-only filesystem?
- Too many files open in the system?
- Filesystem full? */
- die (EX_FILEIO, _("can't create lock file %s: %s "
- "(use -n flag to override)"),
- linktargetfile, strerror (errsv));
- }
- close(i);
+ int errsv, j;
j = link(linktargetfile, MOUNTED_LOCK);
errsv = errno;
- (void) unlink(linktargetfile);
-
if (j == 0)
we_created_lockfile = 1;
if (j < 0 && errsv != EEXIST) {
+ (void) unlink(linktargetfile);
die (EX_FILEIO, _("can't link lock file %s: %s "
"(use -n flag to override)"),
MOUNTED_LOCK, strerror (errsv));
}
- fd = open (MOUNTED_LOCK, O_WRONLY);
+ lockfile_fd = open (MOUNTED_LOCK, O_WRONLY);
- if (fd < 0) {
+ if (lockfile_fd < 0) {
int errsv = errno;
/* Strange... Maybe the file was just deleted? */
- if (errno == ENOENT && tries-- > 0)
+ if (errno == ENOENT && tries-- > 0) {
+ if (tries % 200 == 0)
+ usleep(30);
continue;
+ }
+ (void) unlink(linktargetfile);
die (EX_FILEIO, _("can't open lock file %s: %s "
"(use -n flag to override)"),
MOUNTED_LOCK, strerror (errsv));
@@ -520,7 +526,7 @@ lock_mtab (void) {
if (j == 0) {
/* We made the link. Now claim the lock. */
- if (fcntl (fd, F_SETLK, &flock) == -1) {
+ if (fcntl (lockfile_fd, F_SETLK, &flock) == -1) {
if (verbose) {
int errsv = errno;
printf(_("Can't lock lock file %s: %s\n"),
@@ -528,13 +534,15 @@ lock_mtab (void) {
}
/* proceed anyway */
}
+ (void) unlink(linktargetfile);
} else {
static int tries = 0;
/* Someone else made the link. Wait. */
alarm(LOCK_TIMEOUT);
- if (fcntl (fd, F_SETLKW, &flock) == -1) {
+ if (fcntl (lockfile_fd, F_SETLKW, &flock) == -1) {
int errsv = errno;
+ (void) unlink(linktargetfile);
die (EX_FILEIO, _("can't lock lock file %s: %s"),
MOUNTED_LOCK, (errno == EINTR) ?
_("timed out") : strerror (errsv));
@@ -542,16 +550,18 @@ lock_mtab (void) {
alarm(0);
/* Limit the number of iterations - maybe there
still is some old /etc/mtab~ */
- if (tries++ > 3) {
- if (tries > 5)
- die (EX_FILEIO, _("Cannot create link %s\n"
- "Perhaps there is a stale lock file?\n"),
- MOUNTED_LOCK);
- sleep(1);
- }
+ ++tries;
+ if (tries % 200 == 0)
+ usleep(30);
+ if (tries > 100000) {
+ (void) unlink(linktargetfile);
+ close(lockfile_fd);
+ die (EX_FILEIO, _("Cannot create link %s\n"
+ "Perhaps there is a stale lock file?\n"),
+ MOUNTED_LOCK);
+ }
+ close(lockfile_fd);
}
-
- close(fd);
}
}