>From f1aeb4fd0e399cbd733bb47889d28e0bd15094e7 Mon Sep 17 00:00:00 2001
From: Eric Desrochers <eric.desroch...@canonical.com>
Date: Wed, 28 Sep 2016 10:06:05 -0400
Subject: [PATCH] Change /etc/mtab to /proc/self/mounts
Fix for issues based on the fact that ZFS relies on mtab. (Closes: #839071)
---
cmd/mount_zfs/mount_zfs.c | 14 +++++++-------
cmd/zfs/zfs_main.c | 23 ++++++++++++-----------
cmd/zinject/translate.c | 2 +-
contrib/initramfs/scripts/zfs | 7 +++----
etc/init.d/zfs-functions.in | 2 +-
etc/init.d/zfs-mount.in | 4 ++--
lib/libspl/include/sys/mnttab.h | 2 +-
lib/libzfs/libzfs_dataset.c | 11 ++++++-----
lib/libzfs/libzfs_mount.c | 8 ++++----
lib/libzfs/libzfs_util.c | 6 +++---
scripts/ziltest.sh | 6 +++++-
11 files changed, 45 insertions(+), 40 deletions(-)
diff --git a/cmd/mount_zfs/mount_zfs.c b/cmd/mount_zfs/mount_zfs.c
index bd860cb..0efed90 100644
--- a/cmd/mount_zfs/mount_zfs.c
+++ b/cmd/mount_zfs/mount_zfs.c
@@ -292,11 +292,11 @@ mtab_is_writeable(void)
struct stat st;
int error, fd;
- error = lstat(MNTTAB, &st);
+ error = lstat("/etc/mtab", &st);
if (error || S_ISLNK(st.st_mode))
return (0);
- fd = open(MNTTAB, O_RDWR | O_CREAT, 0644);
+ fd = open("/etc/mtab", O_RDWR | O_CREAT, 0644);
if (fd < 0)
return (0);
@@ -318,21 +318,21 @@ mtab_update(char *dataset, char *mntpoint, char *type, char *mntopts)
mnt.mnt_freq = 0;
mnt.mnt_passno = 0;
- fp = setmntent(MNTTAB, "a+");
+ fp = setmntent("/etc/mtab", "a+");
if (!fp) {
(void) fprintf(stderr, gettext(
- "filesystem '%s' was mounted, but %s "
+ "filesystem '%s' was mounted, but /etc/mtab "
"could not be opened due to error %d\n"),
- dataset, MNTTAB, errno);
+ dataset, errno);
return (MOUNT_FILEIO);
}
error = addmntent(fp, &mnt);
if (error) {
(void) fprintf(stderr, gettext(
- "filesystem '%s' was mounted, but %s "
+ "filesystem '%s' was mounted, but /etc/mtab "
"could not be updated due to error %d\n"),
- dataset, MNTTAB, errno);
+ dataset, errno);
return (MOUNT_FILEIO);
}
diff --git a/cmd/zfs/zfs_main.c b/cmd/zfs/zfs_main.c
index 6fb3559..155e5bb 100644
--- a/cmd/zfs/zfs_main.c
+++ b/cmd/zfs/zfs_main.c
@@ -5978,9 +5978,10 @@ share_mount(int op, int argc, char **argv)
}
/*
- * When mount is given no arguments, go through /etc/mtab and
- * display any active ZFS mounts. We hide any snapshots, since
- * they are controlled automatically.
+ * When mount is given no arguments, go through
+ * /proc/self/mounts and display any active ZFS mounts.
+ * We hide any snapshots, since they are controlled
+ * automatically.
*/
/* Reopen MNTTAB to prevent reading stale data from open file */
@@ -6060,8 +6061,8 @@ unshare_unmount_compare(const void *larg, const void *rarg, void *unused)
/*
* Convenience routine used by zfs_do_umount() and manual_unmount(). Given an
- * absolute path, find the entry /etc/mtab, verify that its a ZFS filesystem,
- * and unmount it appropriately.
+ * absolute path, find the entry /proc/self/mounts, verify that its
+ * a ZFS filesystem, and unmount it appropriately.
*/
static int
unshare_unmount_path(int op, char *path, int flags, boolean_t is_manual)
@@ -6074,7 +6075,7 @@ unshare_unmount_path(int op, char *path, int flags, boolean_t is_manual)
ino_t path_inode;
/*
- * Search for the path in /etc/mtab. Rather than looking for the
+ * Search for the path in /proc/self/mounts. Rather than looking for the
* specific path, which can be fooled by non-standard paths (i.e. ".."
* or "//"), we stat() the path and search for the corresponding
* (major,minor) device pair.
@@ -6105,8 +6106,8 @@ unshare_unmount_path(int op, char *path, int flags, boolean_t is_manual)
"currently mounted\n"), cmdname, path);
return (1);
}
- (void) fprintf(stderr, gettext("warning: %s not in mtab\n"),
- path);
+ (void) fprintf(stderr, gettext("warning: %s not in "
+ "/proc/self/mounts\n"), path);
if ((ret = umount2(path, flags)) != 0)
(void) fprintf(stderr, gettext("%s: %s\n"), path,
strerror(errno));
@@ -6217,9 +6218,9 @@ unshare_unmount(int op, int argc, char **argv)
/*
* We could make use of zfs_for_each() to walk all datasets in
* the system, but this would be very inefficient, especially
- * since we would have to linearly search /etc/mtab for each
- * one. Instead, do one pass through /etc/mtab looking for
- * zfs entries and call zfs_unmount() for each one.
+ * since we would have to linearly search /proc/self/mounts for
+ * each one. Instead, do one pass through /proc/self/mounts
+ * looking for zfs entries and call zfs_unmount() for each one.
*
* Things get a little tricky if the administrator has created
* mountpoints beneath other ZFS filesystems. In this case, we
diff --git a/cmd/zinject/translate.c b/cmd/zinject/translate.c
index 5cc9d9f..adace72 100644
--- a/cmd/zinject/translate.c
+++ b/cmd/zinject/translate.c
@@ -120,7 +120,7 @@ parse_pathname(const char *inpath, char *dataset, char *relpath,
#else
if ((fp = fopen(MNTTAB, "r")) == NULL) {
#endif
- (void) fprintf(stderr, "cannot open /etc/mtab\n");
+ (void) fprintf(stderr, "cannot open %s\n", MNTTAB);
return (-1);
}
diff --git a/contrib/initramfs/scripts/zfs b/contrib/initramfs/scripts/zfs
index 6a78a46..250dc57 100644
--- a/contrib/initramfs/scripts/zfs
+++ b/contrib/initramfs/scripts/zfs
@@ -288,9 +288,8 @@ load_module_initrd()
wait_for_dev
fi
- # zpool import refuse to import without a valid mtab
- [ ! -f /proc/mounts ] && mount proc /proc
- [ ! -f /etc/mtab ] && cat /proc/mounts > /etc/mtab
+ # zpool import refuse to import without a valid /proc/self/mounts
+ [ ! -f /proc/self/mounts ] && mount proc /proc
# Load the module
load_module "zfs" || return 1
@@ -919,7 +918,7 @@ mountroot()
#
# but the MOUNTPOINT prefix is preserved on descendent filesystem
# after the pivot into the regular root, which later breaks things
- # like `zfs mount -a` and the /etc/mtab refresh.
+ # like `zfs mount -a` and the /proc/self/mounts refresh.
#
# * Mount additional filesystems required
# Such as /usr, /var, /usr/local etc.
diff --git a/etc/init.d/zfs-functions.in b/etc/init.d/zfs-functions.in
index acfdf99..97f2ea0 100644
--- a/etc/init.d/zfs-functions.in
+++ b/etc/init.d/zfs-functions.in
@@ -368,7 +368,7 @@ read_mtab()
# Set the variable.
eval export MTAB_$mntpnt=\"$fs\"
fi
- done < /proc/mounts
+ done < /proc/self/mounts
}
in_mtab()
diff --git a/etc/init.d/zfs-mount.in b/etc/init.d/zfs-mount.in
index 05cea9b..87473f2 100755
--- a/etc/init.d/zfs-mount.in
+++ b/etc/init.d/zfs-mount.in
@@ -39,7 +39,7 @@ chkroot() {
if [ "$2" = "/" ]; then
return 0
fi
- done < /etc/mtab
+ done < /proc/self/mounts
return 1
}
@@ -178,7 +178,7 @@ do_start()
check_module_loaded "zfs" || exit 0
- # Ensure / exists in /etc/mtab, if not update mtab accordingly.
+ # Ensure / exists in /proc/self/mounts.
# This should be handled by rc.sysinit but lets be paranoid.
if ! chkroot
then
diff --git a/lib/libspl/include/sys/mnttab.h b/lib/libspl/include/sys/mnttab.h
index 21d8965..026a8fa 100644
--- a/lib/libspl/include/sys/mnttab.h
+++ b/lib/libspl/include/sys/mnttab.h
@@ -38,7 +38,7 @@
#undef MNTTAB
#endif /* MNTTAB */
-#define MNTTAB "/etc/mtab"
+#define MNTTAB "/proc/self/mounts"
#define MNT_LINE_MAX 4096
#define MNT_TOOLONG 1 /* entry exceeds MNT_LINE_MAX */
diff --git a/lib/libzfs/libzfs_dataset.c b/lib/libzfs/libzfs_dataset.c
index dde1a9a..ec0ddf5 100644
--- a/lib/libzfs/libzfs_dataset.c
+++ b/lib/libzfs/libzfs_dataset.c
@@ -1825,9 +1825,9 @@ zfs_unset_recvd_props_mode(zfs_handle_t *zhp, uint64_t *cookie)
* zfs_prop_get_int() are built using this interface.
*
* Certain properties can be overridden using 'mount -o'. In this case, scan
- * the contents of the /etc/mtab entry, searching for the appropriate options.
- * If they differ from the on-disk values, report the current values and mark
- * the source "temporary".
+ * the contents of the /proc/self/mounts entry, searching for the
+ * appropriate options. If they differ from the on-disk values, report the
+ * current values and mark the source "temporary".
*/
static int
get_numeric_property(zfs_handle_t *zhp, zfs_prop_t prop, zprop_source_t *src,
@@ -1898,8 +1898,9 @@ get_numeric_property(zfs_handle_t *zhp, zfs_prop_t prop, zprop_source_t *src,
/*
* Because looking up the mount options is potentially expensive
- * (iterating over all of /etc/mtab), we defer its calculation until
- * we're looking up a property which requires its presence.
+ * (iterating over all of /proc/self/mounts), we defer its
+ * calculation until we're looking up a property which requires
+ * its presence.
*/
if (!zhp->zfs_mntcheck &&
(mntopt_on != NULL || prop == ZFS_PROP_MOUNTED)) {
diff --git a/lib/libzfs/libzfs_mount.c b/lib/libzfs/libzfs_mount.c
index bd874e4..4388adc 100644
--- a/lib/libzfs/libzfs_mount.c
+++ b/lib/libzfs/libzfs_mount.c
@@ -346,8 +346,8 @@ zfs_add_option(zfs_handle_t *zhp, char *options, int len,
return (0);
/*
- * zfs_prop_get_int() to not used to ensure our mount options
- * are not influenced by the current /etc/mtab contents.
+ * zfs_prop_get_int() is not used to ensure our mount options
+ * are not influenced by the current /proc/self/mounts contents.
*/
value = getprop_uint64(zhp, prop, &source);
@@ -1162,8 +1162,8 @@ mountpoint_compare(const void *a, const void *b)
* Unshare and unmount all datasets within the given pool. We don't want to
* rely on traversing the DSL to discover the filesystems within the pool,
* because this may be expensive (if not all of them are mounted), and can fail
- * arbitrarily (on I/O error, for example). Instead, we walk /etc/mtab and
- * gather all the filesystems that are currently mounted.
+ * arbitrarily (on I/O error, for example). Instead, we walk /proc/self/mounts
+ * and gather all the filesystems that are currently mounted.
*/
int
zpool_disable_datasets(zpool_handle_t *zhp, boolean_t force)
diff --git a/lib/libzfs/libzfs_util.c b/lib/libzfs/libzfs_util.c
index 56dfd95..24bc0dd 100755
--- a/lib/libzfs/libzfs_util.c
+++ b/lib/libzfs/libzfs_util.c
@@ -67,9 +67,9 @@ libzfs_error_init(int error)
"loaded.\nTry running '/sbin/modprobe zfs' as root "
"to load them.\n"));
case ENOENT:
- return (dgettext(TEXT_DOMAIN, "The /dev/zfs device is "
- "missing and must be created.\nTry running 'udevadm "
- "trigger' as root to create it.\n"));
+ return (dgettext(TEXT_DOMAIN, "/dev/zfs and /proc/self/mounts "
+ "are required.\nTry running 'udevadm trigger' and 'mount "
+ "-t proc proc /proc' as root.\n"));
case ENOEXEC:
return (dgettext(TEXT_DOMAIN, "The ZFS modules cannot be "
"auto-loaded.\nTry running '/sbin/modprobe zfs' as "
diff --git a/scripts/ziltest.sh b/scripts/ziltest.sh
index 62cf09e..bb81629 100755
--- a/scripts/ziltest.sh
+++ b/scripts/ziltest.sh
@@ -185,7 +185,11 @@ CHECKSUM_BEFORE=$(sha256sum -b "$PAYLOAD")
#
# TX_WRITE (small file with ordering)
#
-cp /etc/mtab $ROOT/small_file
+if is_linux; then
+ cp /proc/self/mounts $ROOT/small_file
+else
+ cp /etc/mtab $ROOT/small_file
+fi
cp /etc/profile $ROOT/small_file
#
--
2.5.0
