Commit 0bb73e42 authored by Linus Torvalds's avatar Linus Torvalds

Merge tag 'afs-next-20190915' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs

Pull AFS updates from David Howells:
 "Here's a set of patches for AFS. The first three are trivial, deleting
  unused symbols and rolling out a wrapper function.

  The fourth and fifth patches make use of the previously added RCU-safe
  request_key facility to allow afs_permission() and afs_d_revalidate()
  to attempt to operate without dropping out of RCU-mode pathwalk. Under
  certain conditions, such as conflict with another client, we still
  have to drop out anyway, take a lock and consult the server"

* tag 'afs-next-20190915' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
  afs: Support RCU pathwalk
  afs: Provide an RCU-capable key lookup
  afs: Use afs_extract_discard() rather than iov_iter_discard()
  afs: remove unused variable 'afs_zero_fid'
  afs: remove unused variable 'afs_voltypes'
parents f60c55a9 a0753c29
......@@ -965,6 +965,58 @@ static struct dentry *afs_lookup(struct inode *dir, struct dentry *dentry,
return d;
}
/*
* Check the validity of a dentry under RCU conditions.
*/
static int afs_d_revalidate_rcu(struct dentry *dentry)
{
struct afs_vnode *dvnode, *vnode;
struct dentry *parent;
struct inode *dir, *inode;
long dir_version, de_version;
_enter("%p", dentry);
/* Check the parent directory is still valid first. */
parent = READ_ONCE(dentry->d_parent);
dir = d_inode_rcu(parent);
if (!dir)
return -ECHILD;
dvnode = AFS_FS_I(dir);
if (test_bit(AFS_VNODE_DELETED, &dvnode->flags))
return -ECHILD;
if (!afs_check_validity(dvnode))
return -ECHILD;
/* We only need to invalidate a dentry if the server's copy changed
* behind our back. If we made the change, it's no problem. Note that
* on a 32-bit system, we only have 32 bits in the dentry to store the
* version.
*/
dir_version = (long)READ_ONCE(dvnode->status.data_version);
de_version = (long)READ_ONCE(dentry->d_fsdata);
if (de_version != dir_version) {
dir_version = (long)READ_ONCE(dvnode->invalid_before);
if (de_version - dir_version < 0)
return -ECHILD;
}
/* Check to see if the vnode referred to by the dentry still
* has a callback.
*/
if (d_really_is_positive(dentry)) {
inode = d_inode_rcu(dentry);
if (inode) {
vnode = AFS_FS_I(inode);
if (!afs_check_validity(vnode))
return -ECHILD;
}
}
return 1; /* Still valid */
}
/*
* check that a dentry lookup hit has found a valid entry
* - NOTE! the hit can be a negative hit too, so we can't assume we have an
......@@ -982,7 +1034,7 @@ static int afs_d_revalidate(struct dentry *dentry, unsigned int flags)
int ret;
if (flags & LOOKUP_RCU)
return -ECHILD;
return afs_d_revalidate_rcu(dentry);
if (d_really_is_positive(dentry)) {
vnode = AFS_FS_I(d_inode(dentry));
......
......@@ -15,8 +15,6 @@
#include "xdr_fs.h"
#include "protocol_yfs.h"
static const struct afs_fid afs_zero_fid;
static inline void afs_use_fs_server(struct afs_call *call, struct afs_cb_interest *cbi)
{
call->cbi = afs_get_cb_interest(cbi);
......@@ -394,7 +392,7 @@ static int afs_deliver_fs_fetch_data(struct afs_call *call)
goto no_more_data;
/* Discard any excess data the server gave us */
iov_iter_discard(&call->iter, READ, req->actual_len - req->len);
afs_extract_discard(call, req->actual_len - req->len);
call->unmarshall = 3;
/* Fall through */
......@@ -1872,7 +1870,7 @@ static int afs_deliver_fs_get_capabilities(struct afs_call *call)
call->count = count;
call->count2 = count;
iov_iter_discard(&call->iter, READ, count * sizeof(__be32));
afs_extract_discard(call, count * sizeof(__be32));
call->unmarshall++;
/* Fall through */
......
......@@ -1217,6 +1217,7 @@ extern void afs_cache_permit(struct afs_vnode *, struct key *, unsigned int,
struct afs_status_cb *);
extern void afs_zap_permits(struct rcu_head *);
extern struct key *afs_request_key(struct afs_cell *);
extern struct key *afs_request_key_rcu(struct afs_cell *);
extern int afs_check_permit(struct afs_vnode *, struct key *, afs_access_t *);
extern int afs_permission(struct inode *, int);
extern void __exit afs_clean_up_permit_cache(void);
......
......@@ -27,8 +27,37 @@ struct key *afs_request_key(struct afs_cell *cell)
_enter("{%x}", key_serial(cell->anonymous_key));
_debug("key %s", cell->anonymous_key->description);
key = request_key(&key_type_rxrpc, cell->anonymous_key->description,
NULL);
key = request_key_net(&key_type_rxrpc, cell->anonymous_key->description,
cell->net->net, NULL);
if (IS_ERR(key)) {
if (PTR_ERR(key) != -ENOKEY) {
_leave(" = %ld", PTR_ERR(key));
return key;
}
/* act as anonymous user */
_leave(" = {%x} [anon]", key_serial(cell->anonymous_key));
return key_get(cell->anonymous_key);
} else {
/* act as authorised user */
_leave(" = {%x} [auth]", key_serial(key));
return key;
}
}
/*
* Get a key when pathwalk is in rcuwalk mode.
*/
struct key *afs_request_key_rcu(struct afs_cell *cell)
{
struct key *key;
_enter("{%x}", key_serial(cell->anonymous_key));
_debug("key %s", cell->anonymous_key->description);
key = request_key_net_rcu(&key_type_rxrpc,
cell->anonymous_key->description,
cell->net->net);
if (IS_ERR(key)) {
if (PTR_ERR(key) != -ENOKEY) {
_leave(" = %ld", PTR_ERR(key));
......@@ -274,6 +303,40 @@ void afs_cache_permit(struct afs_vnode *vnode, struct key *key,
return;
}
static bool afs_check_permit_rcu(struct afs_vnode *vnode, struct key *key,
afs_access_t *_access)
{
const struct afs_permits *permits;
int i;
_enter("{%llx:%llu},%x",
vnode->fid.vid, vnode->fid.vnode, key_serial(key));
/* check the permits to see if we've got one yet */
if (key == vnode->volume->cell->anonymous_key) {
*_access = vnode->status.anon_access;
_leave(" = t [anon %x]", *_access);
return true;
}
permits = rcu_dereference(vnode->permit_cache);
if (permits) {
for (i = 0; i < permits->nr_permits; i++) {
if (permits->permits[i].key < key)
continue;
if (permits->permits[i].key > key)
break;
*_access = permits->permits[i].access;
_leave(" = %u [perm %x]", !permits->invalidated, *_access);
return !permits->invalidated;
}
}
_leave(" = f");
return false;
}
/*
* check with the fileserver to see if the directory or parent directory is
* permitted to be accessed with this authorisation, and if so, what access it
......@@ -340,14 +403,21 @@ int afs_permission(struct inode *inode, int mask)
struct afs_vnode *vnode = AFS_FS_I(inode);
afs_access_t uninitialized_var(access);
struct key *key;
int ret;
if (mask & MAY_NOT_BLOCK)
return -ECHILD;
int ret = 0;
_enter("{{%llx:%llu},%lx},%x,",
vnode->fid.vid, vnode->fid.vnode, vnode->flags, mask);
if (mask & MAY_NOT_BLOCK) {
key = afs_request_key_rcu(vnode->volume->cell);
if (IS_ERR(key))
return -ECHILD;
ret = -ECHILD;
if (!afs_check_validity(vnode) ||
!afs_check_permit_rcu(vnode, key, &access))
goto error;
} else {
key = afs_request_key(vnode->volume->cell);
if (IS_ERR(key)) {
_leave(" = %ld [key]", PTR_ERR(key));
......@@ -362,11 +432,13 @@ int afs_permission(struct inode *inode, int mask)
ret = afs_check_permit(vnode, key, &access);
if (ret < 0)
goto error;
}
/* interpret the access mask */
_debug("REQ %x ACC %x on %s",
mask, access, S_ISDIR(inode->i_mode) ? "dir" : "file");
ret = 0;
if (S_ISDIR(inode->i_mode)) {
if (mask & (MAY_EXEC | MAY_READ | MAY_CHDIR)) {
if (!(access & AFS_ACE_LOOKUP))
......
......@@ -12,8 +12,6 @@
unsigned __read_mostly afs_volume_gc_delay = 10;
unsigned __read_mostly afs_volume_record_life = 60 * 60;
static const char *const afs_voltypes[] = { "R/W", "R/O", "BAK" };
/*
* Allocate a volume record and load it up from a vldb record.
*/
......
......@@ -505,7 +505,7 @@ static int yfs_deliver_fs_fetch_data64(struct afs_call *call)
goto no_more_data;
/* Discard any excess data the server gave us */
iov_iter_discard(&call->iter, READ, req->actual_len - req->len);
afs_extract_discard(call, req->actual_len - req->len);
call->unmarshall = 3;
/* Fall through */
......@@ -2007,7 +2007,7 @@ static int yfs_deliver_fs_fetch_opaque_acl(struct afs_call *call)
acl->size = call->count2;
afs_extract_begin(call, acl->data, size);
} else {
iov_iter_discard(&call->iter, READ, size);
afs_extract_discard(call, size);
}
call->unmarshall++;
/* Fall through */
......@@ -2039,7 +2039,7 @@ static int yfs_deliver_fs_fetch_opaque_acl(struct afs_call *call)
acl->size = call->count2;
afs_extract_begin(call, acl->data, size);
} else {
iov_iter_discard(&call->iter, READ, size);
afs_extract_discard(call, size);
}
call->unmarshall++;
/* Fall through */
......
......@@ -324,7 +324,7 @@ static inline struct key *request_key(struct key_type *type,
}
#ifdef CONFIG_NET
/*
/**
* request_key_net - Request a key for a net namespace and wait for construction
* @type: Type of key.
* @description: The searchable description of the key.
......@@ -341,6 +341,18 @@ static inline struct key *request_key(struct key_type *type,
*/
#define request_key_net(type, description, net, callout_info) \
request_key_tag(type, description, net->key_domain, callout_info);
/**
* request_key_net_rcu - Request a key for a net namespace under RCU conditions
* @type: Type of key.
* @description: The searchable description of the key.
* @net: The network namespace that is the key's domain of operation.
*
* As for request_key_rcu() except that only keys that operate the specified
* network namespace are used.
*/
#define request_key_net_rcu(type, description, net) \
request_key_rcu(type, description, net->key_domain);
#endif /* CONFIG_NET */
extern int wait_for_key_construction(struct key *key, bool intr);
......
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