diff --git a/fs/afs/cell.c b/fs/afs/cell.c
index bb92b54d2a4a74dbdb3bd0ecba60b51daf637b95..f3d0bef16d78b99291c28e39fc266fa59098572d 100644
--- a/fs/afs/cell.c
+++ b/fs/afs/cell.c
@@ -15,6 +15,7 @@
#include <linux/dns_resolver.h>
#include <linux/sched.h>
#include <linux/inet.h>
+#include <linux/namei.h>
#include <keys/rxrpc-type.h>
#include "internal.h"
@@ -531,9 +532,11 @@ static int afs_activate_cell(struct afs_net *net, struct afs_cell *cell)
ret = afs_proc_cell_setup(cell);
if (ret < 0)
return ret;
- spin_lock(&net->proc_cells_lock);
+
+ mutex_lock(&net->proc_cells_lock);
list_add_tail(&cell->proc_link, &net->proc_cells);
- spin_unlock(&net->proc_cells_lock);
+ afs_dynroot_mkdir(net, cell);
+ mutex_unlock(&net->proc_cells_lock);
return 0;
}
@@ -546,9 +549,10 @@ static void afs_deactivate_cell(struct afs_net *net, struct afs_cell *cell)
afs_proc_cell_remove(cell);
- spin_lock(&net->proc_cells_lock);
+ mutex_lock(&net->proc_cells_lock);
list_del_init(&cell->proc_link);
- spin_unlock(&net->proc_cells_lock);
+ afs_dynroot_rmdir(net, cell);
+ mutex_unlock(&net->proc_cells_lock);
#ifdef CONFIG_AFS_FSCACHE
fscache_relinquish_cookie(cell->cache, NULL, false);
diff --git a/fs/afs/dynroot.c b/fs/afs/dynroot.c
index 7425f416ed734a77ddeae53a8b0c0bc36030b614..174e843f06330187e3da4d5f1132493511dd4f5b 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)
@@ -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);
+}
diff --git a/fs/afs/internal.h b/fs/afs/internal.h
index 209e04ffa6c3525a39fbd4a01346272a4b936423..5d8260b4c2b382d7fa18e579776dae07872ecd4a 100644
--- a/fs/afs/internal.h
+++ b/fs/afs/internal.h
@@ -240,7 +240,7 @@ struct afs_net {
atomic_t cells_outstanding;
seqlock_t cells_lock;
- spinlock_t proc_cells_lock;
+ struct mutex proc_cells_lock;
struct list_head proc_cells;
/* Known servers. Theoretically each fileserver can only be in one
@@ -264,6 +264,7 @@ struct afs_net {
struct mutex lock_manager_mutex;
/* Misc */
+ struct super_block *dynroot_sb; /* Dynamic root mount superblock */
struct proc_dir_entry *proc_afs; /* /proc/net/afs directory */
struct afs_sysnames *sysnames;
rwlock_t sysnames_lock;
@@ -722,6 +723,10 @@ extern const struct inode_operations afs_dynroot_inode_operations;
extern const struct dentry_operations afs_dynroot_dentry_operations;
extern struct inode *afs_try_auto_mntpt(struct dentry *, struct inode *);
+extern int afs_dynroot_mkdir(struct afs_net *, struct afs_cell *);
+extern void afs_dynroot_rmdir(struct afs_net *, struct afs_cell *);
+extern int afs_dynroot_populate(struct super_block *);
+extern void afs_dynroot_depopulate(struct super_block *);
/*
* file.c
diff --git a/fs/afs/main.c b/fs/afs/main.c
index 7d2c1354e2ca5e2b1d3e4c53016a22696c63dbe8..e84fe822a960714c8b274435dddbb66f4ba3275a 100644
--- a/fs/afs/main.c
+++ b/fs/afs/main.c
@@ -86,7 +86,7 @@ static int __net_init afs_net_init(struct net *net_ns)
INIT_WORK(&net->cells_manager, afs_manage_cells);
timer_setup(&net->cells_timer, afs_cells_timer, 0);
- spin_lock_init(&net->proc_cells_lock);
+ mutex_init(&net->proc_cells_lock);
INIT_LIST_HEAD(&net->proc_cells);
seqlock_init(&net->fs_lock);
diff --git a/fs/afs/super.c b/fs/afs/super.c
index 8707d867334ee212ee738f0d3619fb8432b30e57..4d3e274207fb7aa05aa320b957a03911984cf67d 100644
--- a/fs/afs/super.c
+++ b/fs/afs/super.c
@@ -355,12 +355,17 @@ static int afs_test_super(struct super_block *sb, void *data)
return (as->net_ns == as1->net_ns &&
as->volume &&
- as->volume->vid == as1->volume->vid);
+ as->volume->vid == as1->volume->vid &&
+ !as->dyn_root);
}
static int afs_dynroot_test_super(struct super_block *sb, void *data)
{
- return false;
+ struct afs_super_info *as1 = data;
+ struct afs_super_info *as = AFS_FS_S(sb);
+
+ return (as->net_ns == as1->net_ns &&
+ as->dyn_root);
}
static int afs_set_super(struct super_block *sb, void *data)
@@ -420,10 +425,14 @@ static int afs_fill_super(struct super_block *sb,
if (!sb->s_root)
goto error;
- if (params->dyn_root)
+ if (as->dyn_root) {
sb->s_d_op = &afs_dynroot_dentry_operations;
- else
+ ret = afs_dynroot_populate(sb);
+ if (ret < 0)
+ goto error;
+ } else {
sb->s_d_op = &afs_fs_dentry_operations;
+ }
_leave(" = 0");
return 0;
@@ -458,6 +467,25 @@ static void afs_destroy_sbi(struct afs_super_info *as)
}
}
+static void afs_kill_super(struct super_block *sb)
+{
+ struct afs_super_info *as = AFS_FS_S(sb);
+ struct afs_net *net = afs_net(as->net_ns);
+
+ if (as->dyn_root)
+ afs_dynroot_depopulate(sb);
+
+ /* Clear the callback interests (which will do ilookup5) before
+ * deactivating the superblock.
+ */
+ if (as->volume)
+ afs_clear_callback_interests(net, as->volume->servers);
+ kill_anon_super(sb);
+ if (as->volume)
+ afs_deactivate_volume(as->volume);
+ afs_destroy_sbi(as);
+}
+
/*
* get an AFS superblock
*/
@@ -566,22 +594,6 @@ static struct dentry *afs_mount(struct file_system_type *fs_type,
return ERR_PTR(ret);
}
-static void afs_kill_super(struct super_block *sb)
-{
- struct afs_super_info *as = AFS_FS_S(sb);
-
- /* Clear the callback interests (which will do ilookup5) before
- * deactivating the superblock.
- */
- if (as->volume)
- afs_clear_callback_interests(afs_net(as->net_ns),
- as->volume->servers);
- kill_anon_super(sb);
- if (as->volume)
- afs_deactivate_volume(as->volume);
- afs_destroy_sbi(as);
-}
-
/*
* Initialise an inode cache slab element prior to any use. Note that
* afs_alloc_inode() *must* reset anything that could incorrectly leak from one
diff --git a/fs/namei.c b/fs/namei.c
index 186bd2464fd5a842480a37c55b57d60d9164cf86..2e0a1c5729f1cf64cc9cac54419dcd1714a41a32 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2463,6 +2463,35 @@ static int lookup_one_len_common(const char *name, struct dentry *base,
return inode_permission(base->d_inode, MAY_EXEC);
}
+/**
+ * try_lookup_one_len - filesystem helper to lookup single pathname component
+ * @name: pathname component to lookup
+ * @base: base directory to lookup from
+ * @len: maximum length @len should be interpreted to
+ *
+ * Look up a dentry by name in the dcache, returning NULL if it does not
+ * currently exist. The function does not try to create a dentry.
+ *
+ * Note that this routine is purely a helper for filesystem usage and should
+ * not be called by generic code.
+ *
+ * The caller must hold base->i_mutex.
+ */
+struct dentry *try_lookup_one_len(const char *name, struct dentry *base, int len)
+{
+ struct qstr this;
+ int err;
+
+ WARN_ON_ONCE(!inode_is_locked(base->d_inode));
+
+ err = lookup_one_len_common(name, base, len, &this);
+ if (err)
+ return ERR_PTR(err);
+
+ return lookup_dcache(&this, base, 0);
+}
+EXPORT_SYMBOL(try_lookup_one_len);
+
/**
* lookup_one_len - filesystem helper to lookup single pathname component
* @name: pathname component to lookup
diff --git a/include/linux/namei.h b/include/linux/namei.h
index a982bb7cd4806f887811b4928e1154f654cd0474..a78606e8e3df7c155410da7a366490354fb9dcb6 100644
--- a/include/linux/namei.h
+++ b/include/linux/namei.h
@@ -81,6 +81,7 @@ extern void done_path_create(struct path *, struct dentry *);
extern struct dentry *kern_path_locked(const char *, struct path *);
extern int kern_path_mountpoint(int, const char *, struct path *, unsigned int);
+extern struct dentry *try_lookup_one_len(const char *, struct dentry *, int);
extern struct dentry *lookup_one_len(const char *, struct dentry *, int);
extern struct dentry *lookup_one_len_unlocked(const char *, struct dentry *, int);