cache.c

   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 }