From: NeilBrown <neilb@suse.com>
To: Steve Dickson <SteveD@redhat.com>
Cc: Linux NFS Mailing list <linux-nfs@vger.kernel.org>
Subject: [PATCH 6/8] mountd: don't add paths to non-mounted export points to pseudo-root
Date: Thu, 14 Jul 2016 12:26:43 +1000 [thread overview]
Message-ID: <20160714022643.5874.27117.stgit@noble> (raw)
In-Reply-To: <20160714021310.5874.22953.stgit@noble>
export points with the "mountpoint" flag should not be exported
if they aren't mounted.
They shouldn't even appear in the pseudo-root filesystem.
So add an appropriate check to v4root_set().
This means that the v4root might need to be recomputed whenever a
filesystem is mounted or unmounted. So when there are export points
with the "mountpoint" flag, check for changes in the mount table.
This is done be measuring the size of /proc/mounts.
Signed-off-by: NeilBrown <neilb@suse.com>
---
support/include/v4root.h | 2 +-
utils/mountd/auth.c | 29 +++++++++++++++++++++++++++--
utils/mountd/v4root.c | 11 ++++++++++-
3 files changed, 38 insertions(+), 4 deletions(-)
diff --git a/support/include/v4root.h b/support/include/v4root.h
index 706c15c70d95..406fd4e43e5a 100644
--- a/support/include/v4root.h
+++ b/support/include/v4root.h
@@ -10,6 +10,6 @@
#define V4ROOT_H
extern int v4root_needed;
-extern void v4root_set(void);
+extern void v4root_set(int *mountpoints_checked);
#endif /* V4ROOT_H */
diff --git a/utils/mountd/auth.c b/utils/mountd/auth.c
index 0881d9a6edba..5bd7e6622307 100644
--- a/utils/mountd/auth.c
+++ b/utils/mountd/auth.c
@@ -77,6 +77,29 @@ check_useipaddr(void)
cache_flush(1);
}
+static int mountpoints_changed(void)
+{
+ static int last_size = 0;
+ int size;
+ int fd;
+ char buf[4096];
+ int n;
+
+ fd = open("/proc/mounts", O_RDONLY);
+ if (fd < 0)
+ /* ignore mountpoint changes if we cannot read /proc/mounts */
+ return 0;
+ size = 0;
+ while ((n = read(fd, buf, sizeof(buf))) > 0)
+ size += n;
+ if (n < 0)
+ return 0;
+ if (size == last_size)
+ return 0;
+ last_size = size;
+ return 1;
+}
+
unsigned int
auth_reload()
{
@@ -84,6 +107,7 @@ auth_reload()
static ino_t last_inode;
static int last_fd = -1;
static unsigned int counter;
+ static int mountpoints_checked = 0;
int fd;
if ((fd = open(_PATH_ETAB, O_RDONLY)) < 0) {
@@ -91,7 +115,8 @@ auth_reload()
} else if (fstat(fd, &stb) < 0) {
xlog(L_FATAL, "couldn't stat %s", _PATH_ETAB);
close(fd);
- } else if (last_fd != -1 && stb.st_ino == last_inode) {
+ } else if (last_fd != -1 && stb.st_ino == last_inode &&
+ (!mountpoints_checked || !mountpoints_changed())) {
/* We opened the etab file before, and its inode
* number hasn't changed since then.
*/
@@ -114,7 +139,7 @@ auth_reload()
memset(&my_client, 0, sizeof(my_client));
xtab_export_read();
check_useipaddr();
- v4root_set();
+ v4root_set(&mountpoints_checked);
++counter;
diff --git a/utils/mountd/v4root.c b/utils/mountd/v4root.c
index d52172592823..1a5778f9c7de 100644
--- a/utils/mountd/v4root.c
+++ b/utils/mountd/v4root.c
@@ -183,7 +183,7 @@ static int v4root_add_parents(nfs_export *exp)
* looking for components of the v4 mount.
*/
void
-v4root_set()
+v4root_set(int *mountpoints_checked)
{
nfs_export *exp;
int i;
@@ -193,6 +193,7 @@ v4root_set()
if (!v4root_support())
return;
+ *mountpoints_checked = 0;
for (i = 0; i < MCL_MAXTYPES; i++) {
for (exp = exportlist[i].p_head; exp; exp = exp->m_next) {
if (exp->m_export.e_flags & NFSEXP_V4ROOT)
@@ -202,6 +203,14 @@ v4root_set()
*/
continue;
+ if (exp->m_export.e_mountpoint) {
+ *mountpoints_checked = 1;
+ if (!is_mountpoint(exp->m_export.e_mountpoint[0]?
+ exp->m_export.e_mountpoint:
+ exp->m_export.e_path))
+ continue;
+ }
+
if (strcmp(exp->m_export.e_path, "/") == 0 &&
!(exp->m_export.e_flags & NFSEXP_FSID)) {
/* Force '/' to be exported as fsid == 0*/
next prev parent reply other threads:[~2016-07-14 2:28 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-14 2:26 [PATCH 0/8] Assorted mount-related nfs-utils patches NeilBrown
2016-07-14 2:26 ` [PATCH 3/8] mountd: remove 'dev_missing' checks NeilBrown
2016-07-18 20:01 ` J. Bruce Fields
2016-07-19 22:50 ` NeilBrown
2016-07-21 17:24 ` J. Bruce Fields
2016-08-11 2:51 ` NeilBrown
2016-08-16 15:21 ` J. Bruce Fields
2016-08-18 1:32 ` NeilBrown
2016-08-18 2:57 ` Chuck Lever
2016-08-19 1:31 ` NeilBrown
2016-08-18 13:57 ` J. Bruce Fields
2016-08-19 1:28 ` NeilBrown
2016-08-19 17:27 ` J. Bruce Fields
2016-07-14 2:26 ` NeilBrown [this message]
2016-07-18 20:32 ` [PATCH 6/8] mountd: don't add paths to non-mounted export points to pseudo-root J. Bruce Fields
2016-07-19 8:00 ` Chuck Lever
2016-07-19 22:59 ` NeilBrown
2016-07-21 17:33 ` J. Bruce Fields
2016-07-25 7:22 ` NeilBrown
2016-07-28 20:54 ` J. Bruce Fields
2016-07-14 2:26 ` [PATCH 4/8] mountd: cause attempts to access unmounted exportpoints to return ESTALE NeilBrown
2016-07-14 2:26 ` [PATCH 2/8] mountd: remove the --exports-file option NeilBrown
2016-07-18 16:19 ` J. Bruce Fields
2016-07-14 2:26 ` [PATCH 1/8] nfs.man: clarify effect of 'retry' option NeilBrown
2016-07-14 2:26 ` [PATCH 5/8] mountd: Don't export unmounted exports to NFSv4 NeilBrown
2016-07-14 2:26 ` [PATCH 7/8] mount: don't treat temporary name resolution failure as permanent NeilBrown
2016-07-19 23:01 ` NeilBrown
2016-07-14 2:26 ` [PATCH 8/8] mount: use a public address for IPv6 callback NeilBrown
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