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Diffstat (limited to 'fs/afs/dynroot.c')
-rw-r--r--fs/afs/dynroot.c126
1 files changed, 124 insertions, 2 deletions
diff --git a/fs/afs/dynroot.c b/fs/afs/dynroot.c
index 983f3946ab57..174e843f0633 100644
--- a/fs/afs/dynroot.c
+++ b/fs/afs/dynroot.c
@@ -1,4 +1,4 @@
-/* dir.c: AFS dynamic root handling
+/* AFS dynamic root handling
*
* Copyright (C) 2018 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
@@ -46,7 +46,7 @@ static int afs_probe_cell_name(struct dentry *dentry)
return 0;
}
- ret = dns_query("afsdb", name, len, "ipv4", NULL, NULL);
+ ret = dns_query("afsdb", name, len, "", NULL, NULL);
if (ret == -ENODATA)
ret = -EDESTADDRREQ;
return ret;
@@ -207,3 +207,125 @@ const struct dentry_operations afs_dynroot_dentry_operations = {
.d_release = afs_d_release,
.d_automount = afs_d_automount,
};
+
+/*
+ * Create a manually added cell mount directory.
+ * - The caller must hold net->proc_cells_lock
+ */
+int afs_dynroot_mkdir(struct afs_net *net, struct afs_cell *cell)
+{
+ struct super_block *sb = net->dynroot_sb;
+ struct dentry *root, *subdir;
+ int ret;
+
+ if (!sb || atomic_read(&sb->s_active) == 0)
+ return 0;
+
+ /* Let the ->lookup op do the creation */
+ root = sb->s_root;
+ inode_lock(root->d_inode);
+ subdir = lookup_one_len(cell->name, root, cell->name_len);
+ if (IS_ERR(subdir)) {
+ ret = PTR_ERR(subdir);
+ goto unlock;
+ }
+
+ /* Note that we're retaining an extra ref on the dentry */
+ subdir->d_fsdata = (void *)1UL;
+ ret = 0;
+unlock:
+ inode_unlock(root->d_inode);
+ return ret;
+}
+
+/*
+ * Remove a manually added cell mount directory.
+ * - The caller must hold net->proc_cells_lock
+ */
+void afs_dynroot_rmdir(struct afs_net *net, struct afs_cell *cell)
+{
+ struct super_block *sb = net->dynroot_sb;
+ struct dentry *root, *subdir;
+
+ if (!sb || atomic_read(&sb->s_active) == 0)
+ return;
+
+ root = sb->s_root;
+ inode_lock(root->d_inode);
+
+ /* Don't want to trigger a lookup call, which will re-add the cell */
+ subdir = try_lookup_one_len(cell->name, root, cell->name_len);
+ if (IS_ERR_OR_NULL(subdir)) {
+ _debug("lookup %ld", PTR_ERR(subdir));
+ goto no_dentry;
+ }
+
+ _debug("rmdir %pd %u", subdir, d_count(subdir));
+
+ if (subdir->d_fsdata) {
+ _debug("unpin %u", d_count(subdir));
+ subdir->d_fsdata = NULL;
+ dput(subdir);
+ }
+ dput(subdir);
+no_dentry:
+ inode_unlock(root->d_inode);
+ _leave("");
+}
+
+/*
+ * Populate a newly created dynamic root with cell names.
+ */
+int afs_dynroot_populate(struct super_block *sb)
+{
+ struct afs_cell *cell;
+ struct afs_net *net = afs_sb2net(sb);
+ int ret;
+
+ if (mutex_lock_interruptible(&net->proc_cells_lock) < 0)
+ return -ERESTARTSYS;
+
+ net->dynroot_sb = sb;
+ list_for_each_entry(cell, &net->proc_cells, proc_link) {
+ ret = afs_dynroot_mkdir(net, cell);
+ if (ret < 0)
+ goto error;
+ }
+
+ ret = 0;
+out:
+ mutex_unlock(&net->proc_cells_lock);
+ return ret;
+
+error:
+ net->dynroot_sb = NULL;
+ goto out;
+}
+
+/*
+ * When a dynamic root that's in the process of being destroyed, depopulate it
+ * of pinned directories.
+ */
+void afs_dynroot_depopulate(struct super_block *sb)
+{
+ struct afs_net *net = afs_sb2net(sb);
+ struct dentry *root = sb->s_root, *subdir, *tmp;
+
+ /* Prevent more subdirs from being created */
+ mutex_lock(&net->proc_cells_lock);
+ if (net->dynroot_sb == sb)
+ net->dynroot_sb = NULL;
+ mutex_unlock(&net->proc_cells_lock);
+
+ inode_lock(root->d_inode);
+
+ /* Remove all the pins for dirs created for manually added cells */
+ list_for_each_entry_safe(subdir, tmp, &root->d_subdirs, d_child) {
+ if (subdir->d_fsdata) {
+ subdir->d_fsdata = NULL;
+ dput(subdir);
+ }
+ }
+
+ inode_unlock(root->d_inode);
+}