Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 778 insertions, 0 deletions

diff --git a/fs/afs/super.c b/fs/afs/super.c
new file mode 100644
index 000000000..e95fb4cb4
--- /dev/null
+++ b/fs/afs/super.c
@@ -0,0 +1,778 @@
+/* AFS superblock handling
+ *
+ * Copyright (c) 2002, 2007, 2018 Red Hat, Inc. All rights reserved.
+ *
+ * This software may be freely redistributed under the terms of the
+ * GNU General Public License.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ * Authors: David Howells <dhowells@redhat.com>
+ *          David Woodhouse <dwmw2@infradead.org>
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mount.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/fs.h>
+#include <linux/pagemap.h>
+#include <linux/fs_parser.h>
+#include <linux/statfs.h>
+#include <linux/sched.h>
+#include <linux/nsproxy.h>
+#include <linux/magic.h>
+#include <net/net_namespace.h>
+#include "internal.h"
+
+static void afs_i_init_once(void *foo);
+static void afs_kill_super(struct super_block *sb);
+static struct inode *afs_alloc_inode(struct super_block *sb);
+static void afs_destroy_inode(struct inode *inode);
+static void afs_free_inode(struct inode *inode);
+static int afs_statfs(struct dentry *dentry, struct kstatfs *buf);
+static int afs_show_devname(struct seq_file *m, struct dentry *root);
+static int afs_show_options(struct seq_file *m, struct dentry *root);
+static int afs_init_fs_context(struct fs_context *fc);
+static const struct fs_parameter_spec afs_fs_parameters[];
+
+struct file_system_type afs_fs_type = {
+	.owner			= THIS_MODULE,
+	.name			= "afs",
+	.init_fs_context	= afs_init_fs_context,
+	.parameters		= afs_fs_parameters,
+	.kill_sb		= afs_kill_super,
+	.fs_flags		= FS_RENAME_DOES_D_MOVE,
+};
+MODULE_ALIAS_FS("afs");
+
+int afs_net_id;
+
+static const struct super_operations afs_super_ops = {
+	.statfs		= afs_statfs,
+	.alloc_inode	= afs_alloc_inode,
+	.write_inode	= afs_write_inode,
+	.drop_inode	= afs_drop_inode,
+	.destroy_inode	= afs_destroy_inode,
+	.free_inode	= afs_free_inode,
+	.evict_inode	= afs_evict_inode,
+	.show_devname	= afs_show_devname,
+	.show_options	= afs_show_options,
+};
+
+static struct kmem_cache *afs_inode_cachep;
+static atomic_t afs_count_active_inodes;
+
+enum afs_param {
+	Opt_autocell,
+	Opt_dyn,
+	Opt_flock,
+	Opt_source,
+};
+
+static const struct constant_table afs_param_flock[] = {
+	{"local",	afs_flock_mode_local },
+	{"openafs",	afs_flock_mode_openafs },
+	{"strict",	afs_flock_mode_strict },
+	{"write",	afs_flock_mode_write },
+	{}
+};
+
+static const struct fs_parameter_spec afs_fs_parameters[] = {
+	fsparam_flag  ("autocell",	Opt_autocell),
+	fsparam_flag  ("dyn",		Opt_dyn),
+	fsparam_enum  ("flock",		Opt_flock, afs_param_flock),
+	fsparam_string("source",	Opt_source),
+	{}
+};
+
+/*
+ * initialise the filesystem
+ */
+int __init afs_fs_init(void)
+{
+	int ret;
+
+	_enter("");
+
+	/* create ourselves an inode cache */
+	atomic_set(&afs_count_active_inodes, 0);
+
+	ret = -ENOMEM;
+	afs_inode_cachep = kmem_cache_create("afs_inode_cache",
+					     sizeof(struct afs_vnode),
+					     0,
+					     SLAB_HWCACHE_ALIGN|SLAB_ACCOUNT,
+					     afs_i_init_once);
+	if (!afs_inode_cachep) {
+		printk(KERN_NOTICE "kAFS: Failed to allocate inode cache\n");
+		return ret;
+	}
+
+	/* now export our filesystem to lesser mortals */
+	ret = register_filesystem(&afs_fs_type);
+	if (ret < 0) {
+		kmem_cache_destroy(afs_inode_cachep);
+		_leave(" = %d", ret);
+		return ret;
+	}
+
+	_leave(" = 0");
+	return 0;
+}
+
+/*
+ * clean up the filesystem
+ */
+void afs_fs_exit(void)
+{
+	_enter("");
+
+	afs_mntpt_kill_timer();
+	unregister_filesystem(&afs_fs_type);
+
+	if (atomic_read(&afs_count_active_inodes) != 0) {
+		printk("kAFS: %d active inode objects still present\n",
+		       atomic_read(&afs_count_active_inodes));
+		BUG();
+	}
+
+	/*
+	 * Make sure all delayed rcu free inodes are flushed before we
+	 * destroy cache.
+	 */
+	rcu_barrier();
+	kmem_cache_destroy(afs_inode_cachep);
+	_leave("");
+}
+
+/*
+ * Display the mount device name in /proc/mounts.
+ */
+static int afs_show_devname(struct seq_file *m, struct dentry *root)
+{
+	struct afs_super_info *as = AFS_FS_S(root->d_sb);
+	struct afs_volume *volume = as->volume;
+	struct afs_cell *cell = as->cell;
+	const char *suf = "";
+	char pref = '%';
+
+	if (as->dyn_root) {
+		seq_puts(m, "none");
+		return 0;
+	}
+
+	switch (volume->type) {
+	case AFSVL_RWVOL:
+		break;
+	case AFSVL_ROVOL:
+		pref = '#';
+		if (volume->type_force)
+			suf = ".readonly";
+		break;
+	case AFSVL_BACKVOL:
+		pref = '#';
+		suf = ".backup";
+		break;
+	}
+
+	seq_printf(m, "%c%s:%s%s", pref, cell->name, volume->name, suf);
+	return 0;
+}
+
+/*
+ * Display the mount options in /proc/mounts.
+ */
+static int afs_show_options(struct seq_file *m, struct dentry *root)
+{
+	struct afs_super_info *as = AFS_FS_S(root->d_sb);
+	const char *p = NULL;
+
+	if (as->dyn_root)
+		seq_puts(m, ",dyn");
+	if (test_bit(AFS_VNODE_AUTOCELL, &AFS_FS_I(d_inode(root))->flags))
+		seq_puts(m, ",autocell");
+	switch (as->flock_mode) {
+	case afs_flock_mode_unset:	break;
+	case afs_flock_mode_local:	p = "local";	break;
+	case afs_flock_mode_openafs:	p = "openafs";	break;
+	case afs_flock_mode_strict:	p = "strict";	break;
+	case afs_flock_mode_write:	p = "write";	break;
+	}
+	if (p)
+		seq_printf(m, ",flock=%s", p);
+
+	return 0;
+}
+
+/*
+ * Parse the source name to get cell name, volume name, volume type and R/W
+ * selector.
+ *
+ * This can be one of the following:
+ *	"%[cell:]volume[.]"		R/W volume
+ *	"#[cell:]volume[.]"		R/O or R/W volume (R/O parent),
+ *					 or R/W (R/W parent) volume
+ *	"%[cell:]volume.readonly"	R/O volume
+ *	"#[cell:]volume.readonly"	R/O volume
+ *	"%[cell:]volume.backup"		Backup volume
+ *	"#[cell:]volume.backup"		Backup volume
+ */
+static int afs_parse_source(struct fs_context *fc, struct fs_parameter *param)
+{
+	struct afs_fs_context *ctx = fc->fs_private;
+	struct afs_cell *cell;
+	const char *cellname, *suffix, *name = param->string;
+	int cellnamesz;
+
+	_enter(",%s", name);
+
+	if (fc->source)
+		return invalf(fc, "kAFS: Multiple sources not supported");
+
+	if (!name) {
+		printk(KERN_ERR "kAFS: no volume name specified\n");
+		return -EINVAL;
+	}
+
+	if ((name[0] != '%' && name[0] != '#') || !name[1]) {
+		/* To use dynroot, we don't want to have to provide a source */
+		if (strcmp(name, "none") == 0) {
+			ctx->no_cell = true;
+			return 0;
+		}
+		printk(KERN_ERR "kAFS: unparsable volume name\n");
+		return -EINVAL;
+	}
+
+	/* determine the type of volume we're looking for */
+	if (name[0] == '%') {
+		ctx->type = AFSVL_RWVOL;
+		ctx->force = true;
+	}
+	name++;
+
+	/* split the cell name out if there is one */
+	ctx->volname = strchr(name, ':');
+	if (ctx->volname) {
+		cellname = name;
+		cellnamesz = ctx->volname - name;
+		ctx->volname++;
+	} else {
+		ctx->volname = name;
+		cellname = NULL;
+		cellnamesz = 0;
+	}
+
+	/* the volume type is further affected by a possible suffix */
+	suffix = strrchr(ctx->volname, '.');
+	if (suffix) {
+		if (strcmp(suffix, ".readonly") == 0) {
+			ctx->type = AFSVL_ROVOL;
+			ctx->force = true;
+		} else if (strcmp(suffix, ".backup") == 0) {
+			ctx->type = AFSVL_BACKVOL;
+			ctx->force = true;
+		} else if (suffix[1] == 0) {
+		} else {
+			suffix = NULL;
+		}
+	}
+
+	ctx->volnamesz = suffix ?
+		suffix - ctx->volname : strlen(ctx->volname);
+
+	_debug("cell %*.*s [%p]",
+	       cellnamesz, cellnamesz, cellname ?: "", ctx->cell);
+
+	/* lookup the cell record */
+	if (cellname) {
+		cell = afs_lookup_cell(ctx->net, cellname, cellnamesz,
+				       NULL, false);
+		if (IS_ERR(cell)) {
+			pr_err("kAFS: unable to lookup cell '%*.*s'\n",
+			       cellnamesz, cellnamesz, cellname ?: "");
+			return PTR_ERR(cell);
+		}
+		afs_unuse_cell(ctx->net, ctx->cell, afs_cell_trace_unuse_parse);
+		afs_see_cell(cell, afs_cell_trace_see_source);
+		ctx->cell = cell;
+	}
+
+	_debug("CELL:%s [%p] VOLUME:%*.*s SUFFIX:%s TYPE:%d%s",
+	       ctx->cell->name, ctx->cell,
+	       ctx->volnamesz, ctx->volnamesz, ctx->volname,
+	       suffix ?: "-", ctx->type, ctx->force ? " FORCE" : "");
+
+	fc->source = param->string;
+	param->string = NULL;
+	return 0;
+}
+
+/*
+ * Parse a single mount parameter.
+ */
+static int afs_parse_param(struct fs_context *fc, struct fs_parameter *param)
+{
+	struct fs_parse_result result;
+	struct afs_fs_context *ctx = fc->fs_private;
+	int opt;
+
+	opt = fs_parse(fc, afs_fs_parameters, param, &result);
+	if (opt < 0)
+		return opt;
+
+	switch (opt) {
+	case Opt_source:
+		return afs_parse_source(fc, param);
+
+	case Opt_autocell:
+		ctx->autocell = true;
+		break;
+
+	case Opt_dyn:
+		ctx->dyn_root = true;
+		break;
+
+	case Opt_flock:
+		ctx->flock_mode = result.uint_32;
+		break;
+
+	default:
+		return -EINVAL;
+	}
+
+	_leave(" = 0");
+	return 0;
+}
+
+/*
+ * Validate the options, get the cell key and look up the volume.
+ */
+static int afs_validate_fc(struct fs_context *fc)
+{
+	struct afs_fs_context *ctx = fc->fs_private;
+	struct afs_volume *volume;
+	struct afs_cell *cell;
+	struct key *key;
+	int ret;
+
+	if (!ctx->dyn_root) {
+		if (ctx->no_cell) {
+			pr_warn("kAFS: Can only specify source 'none' with -o dyn\n");
+			return -EINVAL;
+		}
+
+		if (!ctx->cell) {
+			pr_warn("kAFS: No cell specified\n");
+			return -EDESTADDRREQ;
+		}
+
+	reget_key:
+		/* We try to do the mount securely. */
+		key = afs_request_key(ctx->cell);
+		if (IS_ERR(key))
+			return PTR_ERR(key);
+
+		ctx->key = key;
+
+		if (ctx->volume) {
+			afs_put_volume(ctx->net, ctx->volume,
+				       afs_volume_trace_put_validate_fc);
+			ctx->volume = NULL;
+		}
+
+		if (test_bit(AFS_CELL_FL_CHECK_ALIAS, &ctx->cell->flags)) {
+			ret = afs_cell_detect_alias(ctx->cell, key);
+			if (ret < 0)
+				return ret;
+			if (ret == 1) {
+				_debug("switch to alias");
+				key_put(ctx->key);
+				ctx->key = NULL;
+				cell = afs_use_cell(ctx->cell->alias_of,
+						    afs_cell_trace_use_fc_alias);
+				afs_unuse_cell(ctx->net, ctx->cell, afs_cell_trace_unuse_fc);
+				ctx->cell = cell;
+				goto reget_key;
+			}
+		}
+
+		volume = afs_create_volume(ctx);
+		if (IS_ERR(volume))
+			return PTR_ERR(volume);
+
+		ctx->volume = volume;
+		if (volume->type != AFSVL_RWVOL)
+			ctx->flock_mode = afs_flock_mode_local;
+	}
+
+	return 0;
+}
+
+/*
+ * check a superblock to see if it's the one we're looking for
+ */
+static int afs_test_super(struct super_block *sb, struct fs_context *fc)
+{
+	struct afs_fs_context *ctx = fc->fs_private;
+	struct afs_super_info *as = AFS_FS_S(sb);
+
+	return (as->net_ns == fc->net_ns &&
+		as->volume &&
+		as->volume->vid == ctx->volume->vid &&
+		as->cell == ctx->cell &&
+		!as->dyn_root);
+}
+
+static int afs_dynroot_test_super(struct super_block *sb, struct fs_context *fc)
+{
+	struct afs_super_info *as = AFS_FS_S(sb);
+
+	return (as->net_ns == fc->net_ns &&
+		as->dyn_root);
+}
+
+static int afs_set_super(struct super_block *sb, struct fs_context *fc)
+{
+	return set_anon_super(sb, NULL);
+}
+
+/*
+ * fill in the superblock
+ */
+static int afs_fill_super(struct super_block *sb, struct afs_fs_context *ctx)
+{
+	struct afs_super_info *as = AFS_FS_S(sb);
+	struct inode *inode = NULL;
+	int ret;
+
+	_enter("");
+
+	/* fill in the superblock */
+	sb->s_blocksize		= PAGE_SIZE;
+	sb->s_blocksize_bits	= PAGE_SHIFT;
+	sb->s_maxbytes		= MAX_LFS_FILESIZE;
+	sb->s_magic		= AFS_FS_MAGIC;
+	sb->s_op		= &afs_super_ops;
+	if (!as->dyn_root)
+		sb->s_xattr	= afs_xattr_handlers;
+	ret = super_setup_bdi(sb);
+	if (ret)
+		return ret;
+
+	/* allocate the root inode and dentry */
+	if (as->dyn_root) {
+		inode = afs_iget_pseudo_dir(sb, true);
+	} else {
+		sprintf(sb->s_id, "%llu", as->volume->vid);
+		afs_activate_volume(as->volume);
+		inode = afs_root_iget(sb, ctx->key);
+	}
+
+	if (IS_ERR(inode))
+		return PTR_ERR(inode);
+
+	if (ctx->autocell || as->dyn_root)
+		set_bit(AFS_VNODE_AUTOCELL, &AFS_FS_I(inode)->flags);
+
+	ret = -ENOMEM;
+	sb->s_root = d_make_root(inode);
+	if (!sb->s_root)
+		goto error;
+
+	if (as->dyn_root) {
+		sb->s_d_op = &afs_dynroot_dentry_operations;
+		ret = afs_dynroot_populate(sb);
+		if (ret < 0)
+			goto error;
+	} else {
+		sb->s_d_op = &afs_fs_dentry_operations;
+		rcu_assign_pointer(as->volume->sb, sb);
+	}
+
+	_leave(" = 0");
+	return 0;
+
+error:
+	_leave(" = %d", ret);
+	return ret;
+}
+
+static struct afs_super_info *afs_alloc_sbi(struct fs_context *fc)
+{
+	struct afs_fs_context *ctx = fc->fs_private;
+	struct afs_super_info *as;
+
+	as = kzalloc(sizeof(struct afs_super_info), GFP_KERNEL);
+	if (as) {
+		as->net_ns = get_net(fc->net_ns);
+		as->flock_mode = ctx->flock_mode;
+		if (ctx->dyn_root) {
+			as->dyn_root = true;
+		} else {
+			as->cell = afs_use_cell(ctx->cell, afs_cell_trace_use_sbi);
+			as->volume = afs_get_volume(ctx->volume,
+						    afs_volume_trace_get_alloc_sbi);
+		}
+	}
+	return as;
+}
+
+static void afs_destroy_sbi(struct afs_super_info *as)
+{
+	if (as) {
+		struct afs_net *net = afs_net(as->net_ns);
+		afs_put_volume(net, as->volume, afs_volume_trace_put_destroy_sbi);
+		afs_unuse_cell(net, as->cell, afs_cell_trace_unuse_sbi);
+		put_net(as->net_ns);
+		kfree(as);
+	}
+}
+
+static void afs_kill_super(struct super_block *sb)
+{
+	struct afs_super_info *as = AFS_FS_S(sb);
+
+	if (as->dyn_root)
+		afs_dynroot_depopulate(sb);
+
+	/* Clear the callback interests (which will do ilookup5) before
+	 * deactivating the superblock.
+	 */
+	if (as->volume)
+		rcu_assign_pointer(as->volume->sb, NULL);
+	kill_anon_super(sb);
+	if (as->volume)
+		afs_deactivate_volume(as->volume);
+	afs_destroy_sbi(as);
+}
+
+/*
+ * Get an AFS superblock and root directory.
+ */
+static int afs_get_tree(struct fs_context *fc)
+{
+	struct afs_fs_context *ctx = fc->fs_private;
+	struct super_block *sb;
+	struct afs_super_info *as;
+	int ret;
+
+	ret = afs_validate_fc(fc);
+	if (ret)
+		goto error;
+
+	_enter("");
+
+	/* allocate a superblock info record */
+	ret = -ENOMEM;
+	as = afs_alloc_sbi(fc);
+	if (!as)
+		goto error;
+	fc->s_fs_info = as;
+
+	/* allocate a deviceless superblock */
+	sb = sget_fc(fc,
+		     as->dyn_root ? afs_dynroot_test_super : afs_test_super,
+		     afs_set_super);
+	if (IS_ERR(sb)) {
+		ret = PTR_ERR(sb);
+		goto error;
+	}
+
+	if (!sb->s_root) {
+		/* initial superblock/root creation */
+		_debug("create");
+		ret = afs_fill_super(sb, ctx);
+		if (ret < 0)
+			goto error_sb;
+		sb->s_flags |= SB_ACTIVE;
+	} else {
+		_debug("reuse");
+		ASSERTCMP(sb->s_flags, &, SB_ACTIVE);
+	}
+
+	fc->root = dget(sb->s_root);
+	trace_afs_get_tree(as->cell, as->volume);
+	_leave(" = 0 [%p]", sb);
+	return 0;
+
+error_sb:
+	deactivate_locked_super(sb);
+error:
+	_leave(" = %d", ret);
+	return ret;
+}
+
+static void afs_free_fc(struct fs_context *fc)
+{
+	struct afs_fs_context *ctx = fc->fs_private;
+
+	afs_destroy_sbi(fc->s_fs_info);
+	afs_put_volume(ctx->net, ctx->volume, afs_volume_trace_put_free_fc);
+	afs_unuse_cell(ctx->net, ctx->cell, afs_cell_trace_unuse_fc);
+	key_put(ctx->key);
+	kfree(ctx);
+}
+
+static const struct fs_context_operations afs_context_ops = {
+	.free		= afs_free_fc,
+	.parse_param	= afs_parse_param,
+	.get_tree	= afs_get_tree,
+};
+
+/*
+ * Set up the filesystem mount context.
+ */
+static int afs_init_fs_context(struct fs_context *fc)
+{
+	struct afs_fs_context *ctx;
+	struct afs_cell *cell;
+
+	ctx = kzalloc(sizeof(struct afs_fs_context), GFP_KERNEL);
+	if (!ctx)
+		return -ENOMEM;
+
+	ctx->type = AFSVL_ROVOL;
+	ctx->net = afs_net(fc->net_ns);
+
+	/* Default to the workstation cell. */
+	cell = afs_find_cell(ctx->net, NULL, 0, afs_cell_trace_use_fc);
+	if (IS_ERR(cell))
+		cell = NULL;
+	ctx->cell = cell;
+
+	fc->fs_private = ctx;
+	fc->ops = &afs_context_ops;
+	return 0;
+}
+
+/*
+ * Initialise an inode cache slab element prior to any use.  Note that
+ * afs_alloc_inode() *must* reset anything that could incorrectly leak from one
+ * inode to another.
+ */
+static void afs_i_init_once(void *_vnode)
+{
+	struct afs_vnode *vnode = _vnode;
+
+	memset(vnode, 0, sizeof(*vnode));
+	inode_init_once(&vnode->netfs.inode);
+	mutex_init(&vnode->io_lock);
+	init_rwsem(&vnode->validate_lock);
+	spin_lock_init(&vnode->wb_lock);
+	spin_lock_init(&vnode->lock);
+	INIT_LIST_HEAD(&vnode->wb_keys);
+	INIT_LIST_HEAD(&vnode->pending_locks);
+	INIT_LIST_HEAD(&vnode->granted_locks);
+	INIT_DELAYED_WORK(&vnode->lock_work, afs_lock_work);
+	INIT_LIST_HEAD(&vnode->cb_mmap_link);
+	seqlock_init(&vnode->cb_lock);
+}
+
+/*
+ * allocate an AFS inode struct from our slab cache
+ */
+static struct inode *afs_alloc_inode(struct super_block *sb)
+{
+	struct afs_vnode *vnode;
+
+	vnode = alloc_inode_sb(sb, afs_inode_cachep, GFP_KERNEL);
+	if (!vnode)
+		return NULL;
+
+	atomic_inc(&afs_count_active_inodes);
+
+	/* Reset anything that shouldn't leak from one inode to the next. */
+	memset(&vnode->fid, 0, sizeof(vnode->fid));
+	memset(&vnode->status, 0, sizeof(vnode->status));
+	afs_vnode_set_cache(vnode, NULL);
+
+	vnode->volume		= NULL;
+	vnode->lock_key		= NULL;
+	vnode->permit_cache	= NULL;
+
+	vnode->flags		= 1 << AFS_VNODE_UNSET;
+	vnode->lock_state	= AFS_VNODE_LOCK_NONE;
+
+	init_rwsem(&vnode->rmdir_lock);
+	INIT_WORK(&vnode->cb_work, afs_invalidate_mmap_work);
+
+	_leave(" = %p", &vnode->netfs.inode);
+	return &vnode->netfs.inode;
+}
+
+static void afs_free_inode(struct inode *inode)
+{
+	kmem_cache_free(afs_inode_cachep, AFS_FS_I(inode));
+}
+
+/*
+ * destroy an AFS inode struct
+ */
+static void afs_destroy_inode(struct inode *inode)
+{
+	struct afs_vnode *vnode = AFS_FS_I(inode);
+
+	_enter("%p{%llx:%llu}", inode, vnode->fid.vid, vnode->fid.vnode);
+
+	_debug("DESTROY INODE %p", inode);
+
+	atomic_dec(&afs_count_active_inodes);
+}
+
+static void afs_get_volume_status_success(struct afs_operation *op)
+{
+	struct afs_volume_status *vs = &op->volstatus.vs;
+	struct kstatfs *buf = op->volstatus.buf;
+
+	if (vs->max_quota == 0)
+		buf->f_blocks = vs->part_max_blocks;
+	else
+		buf->f_blocks = vs->max_quota;
+
+	if (buf->f_blocks > vs->blocks_in_use)
+		buf->f_bavail = buf->f_bfree =
+			buf->f_blocks - vs->blocks_in_use;
+}
+
+static const struct afs_operation_ops afs_get_volume_status_operation = {
+	.issue_afs_rpc	= afs_fs_get_volume_status,
+	.issue_yfs_rpc	= yfs_fs_get_volume_status,
+	.success	= afs_get_volume_status_success,
+};
+
+/*
+ * return information about an AFS volume
+ */
+static int afs_statfs(struct dentry *dentry, struct kstatfs *buf)
+{
+	struct afs_super_info *as = AFS_FS_S(dentry->d_sb);
+	struct afs_operation *op;
+	struct afs_vnode *vnode = AFS_FS_I(d_inode(dentry));
+
+	buf->f_type	= dentry->d_sb->s_magic;
+	buf->f_bsize	= AFS_BLOCK_SIZE;
+	buf->f_namelen	= AFSNAMEMAX - 1;
+
+	if (as->dyn_root) {
+		buf->f_blocks	= 1;
+		buf->f_bavail	= 0;
+		buf->f_bfree	= 0;
+		return 0;
+	}
+
+	op = afs_alloc_operation(NULL, as->volume);
+	if (IS_ERR(op))
+		return PTR_ERR(op);
+
+	afs_op_set_vnode(op, 0, vnode);
+	op->nr_files		= 1;
+	op->volstatus.buf	= buf;
+	op->ops			= &afs_get_volume_status_operation;
+	return afs_do_sync_operation(op);
+}