xref: /openbmc/linux/fs/9p/cache.c (revision 0f4d44f6)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * V9FS cache definitions.
4  *
5  *  Copyright (C) 2009 by Abhishek Kulkarni <adkulkar@umail.iu.edu>
6  */
7 
8 #include <linux/jiffies.h>
9 #include <linux/file.h>
10 #include <linux/slab.h>
11 #include <linux/stat.h>
12 #include <linux/sched.h>
13 #include <linux/fs.h>
14 #include <net/9p/9p.h>
15 
16 #include "v9fs.h"
17 #include "cache.h"
18 
19 int v9fs_cache_session_get_cookie(struct v9fs_session_info *v9ses,
20 				  const char *dev_name)
21 {
22 	struct fscache_volume *vcookie;
23 	char *name, *p;
24 
25 	name = kasprintf(GFP_KERNEL, "9p,%s,%s",
26 			 dev_name, v9ses->cachetag ?: v9ses->aname);
27 	if (!name)
28 		return -ENOMEM;
29 
30 	for (p = name; *p; p++)
31 		if (*p == '/')
32 			*p = ';';
33 
34 	vcookie = fscache_acquire_volume(name, NULL, NULL, 0);
35 	p9_debug(P9_DEBUG_FSC, "session %p get volume %p (%s)\n",
36 		 v9ses, vcookie, name);
37 	if (IS_ERR(vcookie)) {
38 		if (vcookie != ERR_PTR(-EBUSY)) {
39 			kfree(name);
40 			return PTR_ERR(vcookie);
41 		}
42 		pr_err("Cache volume key already in use (%s)\n", name);
43 		vcookie = NULL;
44 	}
45 	v9ses->fscache = vcookie;
46 	kfree(name);
47 	return 0;
48 }
49 
50 void v9fs_cache_inode_get_cookie(struct inode *inode)
51 {
52 	struct v9fs_inode *v9inode = V9FS_I(inode);
53 	struct v9fs_session_info *v9ses;
54 	__le32 version;
55 	__le64 path;
56 
57 	if (!S_ISREG(inode->i_mode))
58 		return;
59 	if (WARN_ON(v9fs_inode_cookie(v9inode)))
60 		return;
61 
62 	version = cpu_to_le32(v9inode->qid.version);
63 	path = cpu_to_le64(v9inode->qid.path);
64 	v9ses = v9fs_inode2v9ses(inode);
65 	v9inode->netfs.cache =
66 		fscache_acquire_cookie(v9fs_session_cache(v9ses),
67 				       0,
68 				       &path, sizeof(path),
69 				       &version, sizeof(version),
70 				       i_size_read(&v9inode->netfs.inode));
71 	if (v9inode->netfs.cache)
72 		mapping_set_release_always(inode->i_mapping);
73 
74 	p9_debug(P9_DEBUG_FSC, "inode %p get cookie %p\n",
75 		 inode, v9fs_inode_cookie(v9inode));
76 }
77