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

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

fs/afs/dir.c

+53 −1
Original line number Diff line number Diff line
@@ -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));

fs/afs/fsclient.c

+2 −4
Original line number Diff line number Diff line
@@ -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 */

fs/afs/internal.h

+1 −0
Original line number Diff line number Diff line
@@ -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);

fs/afs/security.c

+90 −18
Original line number Diff line number Diff line
@@ -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))

fs/afs/volume.c

+0 −2
Original line number Diff line number Diff line
@@ -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.

 */