autofs/SOURCES/autofs-5.1.7-add-mount-and-umount-offsets-functions.patch

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2021-11-04 00:41:29 +00:00
autofs-5.1.7 - add mount and umount offsets functions
From: Ian Kent <raven@themaw.net>
Add tree_mapent_mount_offsets() and tree_mapent_umount_offsets() to
the mapent tree handling implementation.
Signed-off-by: Ian Kent <raven@themaw.net>
---
CHANGELOG | 1
include/mounts.h | 2
lib/mounts.c | 260 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 263 insertions(+)
diff --git a/CHANGELOG b/CHANGELOG
index 0bd6f181..892f7581 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -39,6 +39,7 @@
- fix mount_fullpath().
- add tree_mapent_cleanup_offsets().
- add set_offset_tree_catatonic().
+- add mount and umount offsets functions.
25/01/2021 autofs-5.1.7
- make bind mounts propagation slave by default.
diff --git a/include/mounts.h b/include/mounts.h
index 5441ee0e..e56f80ba 100644
--- a/include/mounts.h
+++ b/include/mounts.h
@@ -172,6 +172,8 @@ struct tree_node *tree_mapent_root(struct mapent *me);
int tree_mapent_add_node(struct mapent_cache *mc, const char *base, const char *key);
int tree_mapent_delete_offsets(struct mapent_cache *mc, const char *key);
void tree_mapent_cleanup_offsets(struct mapent *oe);
+int tree_mapent_mount_offsets(struct mapent *oe, int nonstrict);
+int tree_mapent_umount_offsets(struct mapent *oe, int nonstrict);
int unlink_mount_tree(struct autofs_point *ap, const char *mp);
void free_mnt_list(struct mnt_list *list);
int is_mounted(const char *mp, unsigned int type);
diff --git a/lib/mounts.c b/lib/mounts.c
index f075a27e..f7c29475 100644
--- a/lib/mounts.c
+++ b/lib/mounts.c
@@ -1692,6 +1692,266 @@ void tree_mapent_cleanup_offsets(struct mapent *oe)
}
}
+static int tree_mapent_rmdir_path_offset(struct autofs_point *ap, struct mapent *oe)
+{
+ struct mapent *mm_root = MAPENT(MAPENT_ROOT(oe));
+ char *dir, *path;
+ unsigned int split;
+ int ret;
+
+ if (ap->type == LKP_DIRECT)
+ return rmdir_path(ap, oe->key, mm_root->dev);
+
+ dir = strdup(oe->key);
+
+ if (ap->flags & MOUNT_FLAG_GHOST)
+ split = ap->len + mm_root->len + 1;
+ else
+ split = ap->len;
+
+ dir[split] = '\0';
+ path = &dir[split + 1];
+
+ if (chdir(dir) == -1) {
+ error(ap->logopt, "failed to chdir to %s", dir);
+ free(dir);
+ return -1;
+ }
+
+ ret = rmdir_path(ap, path, ap->dev);
+
+ free(dir);
+
+ if (chdir("/") == -1)
+ error(ap->logopt, "failed to chdir to /");
+
+ return ret;
+}
+
+static int tree_mapent_mount_offset(struct mapent *oe, void *ptr)
+{
+ struct traverse_subtree_context *ctxt = ptr;
+ struct autofs_point *ap = ctxt->ap;
+ int ret;
+
+ debug(ap->logopt, "mount offset %s", oe->key);
+
+ ret = mount_autofs_offset(ap, oe);
+ if (ret < MOUNT_OFFSET_OK) {
+ if (ret != MOUNT_OFFSET_IGNORE) {
+ warn(ap->logopt, "failed to mount offset");
+ return 0;
+ } else {
+ debug(ap->logopt,
+ "ignoring \"nohide\" trigger %s", oe->key);
+ /*
+ * Ok, so we shouldn't modify the mapent but
+ * mount requests are blocked at a point above
+ * this and expire only uses the mapent key or
+ * holds the cache write lock.
+ */
+ free(oe->mapent);
+ oe->mapent = NULL;
+ }
+ }
+
+ return 1;
+}
+
+static int tree_mapent_umount_offset(struct mapent *oe, void *ptr)
+{
+ struct traverse_subtree_context *ctxt = ptr;
+ struct autofs_point *ap = ctxt->ap;
+ int ret = 1;
+
+ /*
+ * Check for and umount subtree offsets resulting from
+ * nonstrict mount fail.
+ */
+ ret = tree_mapent_umount_offsets(oe, ctxt->strict);
+ if (!ret)
+ return 0;
+
+ /*
+ * If an offset that has an active mount has been removed
+ * from the multi-mount we don't want to attempt to trigger
+ * mounts for it. Obviously this is because it has been
+ * removed, but less obvious is the potential strange
+ * behaviour that can result if we do try and mount it
+ * again after it's been expired. For example, if an NFS
+ * file system is no longer exported and is later umounted
+ * it can be mounted again without any error message but
+ * shows as an empty directory. That's going to confuse
+ * people for sure.
+ *
+ * If the mount cannot be umounted (the process is now
+ * using a stale mount) the offset needs to be invalidated
+ * so no further mounts will be attempted but the offset
+ * cache entry must remain so expires can continue to
+ * attempt to umount it. If the mount can be umounted and
+ * the offset is removed, at least for NFS we will get
+ * ESTALE errors when attempting list the directory.
+ */
+ if (oe->ioctlfd != -1 ||
+ is_mounted(oe->key, MNTS_REAL)) {
+ if (umount_ent(ap, oe->key) &&
+ is_mounted(oe->key, MNTS_REAL)) {
+ debug(ap->logopt,
+ "offset %s has active mount, invalidate",
+ oe->key);
+ /*
+ * Ok, so we shouldn't modify the mapent but
+ * mount requests are blocked at a point above
+ * this and expire only uses the mapent key or
+ * holds the cache write lock.
+ */
+ if (oe->mapent) {
+ free(oe->mapent);
+ oe->mapent = NULL;
+ }
+ return 0;
+ }
+ }
+
+ /* Don't bother if there's noting to umount. */
+ if (!is_mounted(oe->key, MNTS_AUTOFS))
+ goto done;
+
+ debug(ap->logopt, "umount offset %s", oe->key);
+
+ if (umount_autofs_offset(ap, oe)) {
+ warn(ap->logopt, "failed to umount offset");
+ ret = 0;
+ } else {
+ struct stat st;
+ int ret;
+
+ if (!(oe->flags & MOUNT_FLAG_DIR_CREATED))
+ goto done;
+
+ /*
+ * An error due to partial directory removal is
+ * ok so only try and remount the offset if the
+ * actual mount point still exists.
+ */
+ ret = tree_mapent_rmdir_path_offset(ap, oe);
+ if (ret == -1 && !stat(oe->key, &st)) {
+ ret = tree_mapent_mount_offset(oe, ctxt);
+ /* But we did origianlly create this */
+ oe->flags |= MOUNT_FLAG_DIR_CREATED;
+ }
+ }
+done:
+ return ret;
+}
+
+static int tree_mapent_mount_offsets_work(struct tree_node *n, void *ptr)
+{
+ struct traverse_subtree_context *ctxt = ptr;
+ struct mapent *oe = MAPENT(n);
+ struct mapent *mm_root = MAPENT(MAPENT_ROOT(oe));
+ struct autofs_point *ap = ctxt->ap;
+ int ret;
+
+ if (!oe->mapent)
+ return 1;
+
+ /* Stale offset, no longer present in the mapent */
+ if (oe->age != mm_root->age) {
+ /* Best effort */
+ tree_mapent_umount_offset(oe, ctxt);
+ return 1;
+ }
+
+ ret = tree_mapent_mount_offset(oe, ctxt);
+
+ /*
+ * If re-constructing a multi-mount it's necessary to walk
+ * into nested mounts, unlike the usual "mount only what's
+ * needed as you go" behavior.
+ */
+ if (ap->state == ST_READMAP && ap->flags & MOUNT_FLAG_REMOUNT) {
+ if (oe->ioctlfd != -1 ||
+ is_mounted(oe->key, MNTS_REAL))
+ /* Best effort */
+ tree_mapent_mount_offsets(oe, !ctxt->strict);
+ }
+
+ return ret;
+}
+
+int tree_mapent_mount_offsets(struct mapent *oe, int nonstrict)
+{
+ struct tree_node *base = MAPENT_NODE(oe);
+ struct traverse_subtree_context ctxt = {
+ .ap = oe->mc->ap,
+ .base = base,
+ .strict = !nonstrict,
+ };
+
+ return tree_mapent_traverse_subtree(base,
+ tree_mapent_mount_offsets_work, &ctxt);
+}
+
+static int tree_mapent_umount_offsets_work(struct tree_node *n, void *ptr)
+{
+ struct mapent *oe = MAPENT(n);
+
+ return tree_mapent_umount_offset(oe, ptr);
+}
+
+int tree_mapent_umount_offsets(struct mapent *oe, int nonstrict)
+{
+ struct tree_node *base = MAPENT_NODE(oe);
+ struct autofs_point *ap = oe->mc->ap;
+ struct traverse_subtree_context ctxt = {
+ .ap = ap,
+ .base = base,
+ .strict = !nonstrict,
+ };
+ int ret;
+
+ ret = tree_mapent_traverse_subtree(base,
+ tree_mapent_umount_offsets_work, &ctxt);
+ if (ret && tree_mapent_is_root(oe)) {
+ char mp[PATH_MAX + 1];
+
+ /*
+ * The map entry cache stores mapent keys. For indirect
+ * mount maps they are single direcory components so when
+ * one of these keys is the root of a multi-mount the mount
+ * path must be constructed.
+ */
+ if (!mount_fullpath(mp, PATH_MAX, ap->path, oe->key)) {
+ error(ap->logopt, "mount path is too long");
+ return 0;
+ }
+
+ /*
+ * Special case.
+ * If we can't umount the root container then we can't
+ * delete the offsets from the cache and we need to put
+ * the offset triggers back.
+ */
+ if (is_mounted(mp, MNTS_REAL)) {
+ info(ap->logopt, "unmounting dir = %s", mp);
+ if (umount_ent(ap, mp) &&
+ is_mounted(mp, MNTS_REAL)) {
+ if (!tree_mapent_mount_offsets(oe, 1))
+ warn(ap->logopt,
+ "failed to remount offset triggers");
+ return 0;
+ }
+ }
+
+ /* check for mounted mount entry and remove it if found */
+ mnts_remove_mount(mp, MNTS_MOUNTED);
+
+ }
+
+ return ret;
+}
+
/* From glibc decode_name() */
/* Since the values in a line are separated by spaces, a name cannot
* contain a space. Therefore some programs encode spaces in names