fscache.c

  1// SPDX-License-Identifier: LGPL-2.1
  2/*
  3 *   CIFS filesystem cache interface
  4 *
  5 *   Copyright (c) 2010 Novell, Inc.
  6 *   Author(s): Suresh Jayaraman <sjayaraman@suse.de>
  7 *
  8 */
  9#include "fscache.h"
 10#include "cifsglob.h"
 11#include "cifs_debug.h"
 12#include "cifs_fs_sb.h"
 13#include "cifsproto.h"
 14
 15/*
 16 * Key for fscache inode.  [!] Contents must match comparisons in cifs_find_inode().
 17 */
 18struct cifs_fscache_inode_key {
 19
 20	__le64  uniqueid;	/* server inode number */
 21	__le64  createtime;	/* creation time on server */
 22	u8	type;		/* S_IFMT file type */
 23} __packed;
 24
 25static void cifs_fscache_fill_volume_coherency(
 26	struct cifs_tcon *tcon,
 27	struct cifs_fscache_volume_coherency_data *cd)
 28{
 29	memset(cd, 0, sizeof(*cd));
 30	cd->resource_id		= cpu_to_le64(tcon->resource_id);
 31	cd->vol_create_time	= tcon->vol_create_time;
 32	cd->vol_serial_number	= cpu_to_le32(tcon->vol_serial_number);
 33}
 34
 35int cifs_fscache_get_super_cookie(struct cifs_tcon *tcon)
 36{
 37	struct cifs_fscache_volume_coherency_data cd;
 38	struct TCP_Server_Info *server = tcon->ses->server;
 39	struct fscache_volume *vcookie;
 40	const struct sockaddr *sa = (struct sockaddr *)&server->dstaddr;
 41	size_t slen, i;
 42	char *sharename;
 43	char *key;
 44	int ret = -ENOMEM;
 45
 46	if (tcon->fscache_acquired)
 47		return 0;
 48
 49	mutex_lock(&tcon->fscache_lock);
 50	if (tcon->fscache_acquired) {
 51		mutex_unlock(&tcon->fscache_lock);
 52		return 0;
 53	}
 54	tcon->fscache_acquired = true;
 55
 56	tcon->fscache = NULL;
 57	switch (sa->sa_family) {
 58	case AF_INET:
 59	case AF_INET6:
 60		break;
 61	default:
 62		mutex_unlock(&tcon->fscache_lock);
 63		cifs_dbg(VFS, "Unknown network family '%d'\n", sa->sa_family);
 64		return -EINVAL;
 65	}
 66
 67	memset(&key, 0, sizeof(key));
 68
 69	sharename = extract_sharename(tcon->tree_name);
 70	if (IS_ERR(sharename)) {
 71		mutex_unlock(&tcon->fscache_lock);
 72		cifs_dbg(FYI, "%s: couldn't extract sharename\n", __func__);
 73		return PTR_ERR(sharename);
 74	}
 75
 76	slen = strlen(sharename);
 77	for (i = 0; i < slen; i++)
 78		if (sharename[i] == '/')
 79			sharename[i] = ';';
 80
 81	key = kasprintf(GFP_KERNEL, "cifs,%pISpc,%s", sa, sharename);
 82	if (!key)
 83		goto out;
 84
 85	cifs_fscache_fill_volume_coherency(tcon, &cd);
 86	vcookie = fscache_acquire_volume(key,
 87					 NULL, /* preferred_cache */
 88					 &cd, sizeof(cd));
 89	cifs_dbg(FYI, "%s: (%s/0x%p)\n", __func__, key, vcookie);
 90	if (IS_ERR(vcookie)) {
 91		if (vcookie != ERR_PTR(-EBUSY)) {
 92			ret = PTR_ERR(vcookie);
 93			goto out_2;
 94		}
 95		pr_err("Cache volume key already in use (%s)\n", key);
 96		vcookie = NULL;
 97		trace_smb3_tcon_ref(tcon->debug_id, tcon->tc_count,
 98				    netfs_trace_tcon_ref_see_fscache_collision);
 99	} else {
100		trace_smb3_tcon_ref(tcon->debug_id, tcon->tc_count,
101				    netfs_trace_tcon_ref_see_fscache_okay);
102	}
103
104	tcon->fscache = vcookie;
105	ret = 0;
106out_2:
107	kfree(key);
108out:
109	kfree(sharename);
110	mutex_unlock(&tcon->fscache_lock);
111	return ret;
112}
113
114void cifs_fscache_release_super_cookie(struct cifs_tcon *tcon)
115{
116	struct cifs_fscache_volume_coherency_data cd;
117
118	cifs_dbg(FYI, "%s: (0x%p)\n", __func__, tcon->fscache);
119
120	cifs_fscache_fill_volume_coherency(tcon, &cd);
121	fscache_relinquish_volume(tcon->fscache, &cd, false);
122	tcon->fscache = NULL;
123	trace_smb3_tcon_ref(tcon->debug_id, tcon->tc_count,
124			    netfs_trace_tcon_ref_see_fscache_relinq);
125}
126
127void cifs_fscache_get_inode_cookie(struct inode *inode)
128{
129	struct cifs_fscache_inode_coherency_data cd;
130	struct cifs_fscache_inode_key key;
131	struct cifsInodeInfo *cifsi = CIFS_I(inode);
132	struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
133	struct cifs_tcon *tcon = cifs_sb_master_tcon(cifs_sb);
134
135	key.uniqueid	= cpu_to_le64(cifsi->uniqueid);
136	key.createtime	= cpu_to_le64(cifsi->createtime);
137	key.type	= (inode->i_mode & S_IFMT) >> 12;
138	cifs_fscache_fill_coherency(&cifsi->netfs.inode, &cd);
139
140	cifsi->netfs.cache =
141		fscache_acquire_cookie(tcon->fscache, 0,
142				       &key, sizeof(key),
143				       &cd, sizeof(cd),
144				       i_size_read(&cifsi->netfs.inode));
145	if (cifsi->netfs.cache)
146		mapping_set_release_always(inode->i_mapping);
147}
148
149void cifs_fscache_unuse_inode_cookie(struct inode *inode, bool update)
150{
151	if (update) {
152		struct cifs_fscache_inode_coherency_data cd;
153		loff_t i_size = i_size_read(inode);
154
155		cifs_fscache_fill_coherency(inode, &cd);
156		fscache_unuse_cookie(cifs_inode_cookie(inode), &cd, &i_size);
157	} else {
158		fscache_unuse_cookie(cifs_inode_cookie(inode), NULL, NULL);
159	}
160}
161
162void cifs_fscache_release_inode_cookie(struct inode *inode)
163{
164	struct cifsInodeInfo *cifsi = CIFS_I(inode);
165	struct fscache_cookie *cookie = cifs_inode_cookie(inode);
166
167	if (cookie) {
168		cifs_dbg(FYI, "%s: (0x%p)\n", __func__, cookie);
169		fscache_relinquish_cookie(cookie, false);
170		cifsi->netfs.cache = NULL;
171	}
172}