blob: 8a2370341c7adef9188b23255261b5532ab1f22b [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * Cache operations for Coda.
3 * For Linux 2.1: (C) 1997 Carnegie Mellon University
4 * For Linux 2.3: (C) 2000 Carnegie Mellon University
5 *
6 * Carnegie Mellon encourages users of this code to contribute improvements
7 * to the Coda project http://www.coda.cs.cmu.edu/ <coda@cs.cmu.edu>.
8 */
9
10#include <linux/types.h>
11#include <linux/kernel.h>
12#include <linux/time.h>
13#include <linux/fs.h>
14#include <linux/stat.h>
15#include <linux/errno.h>
16#include <asm/uaccess.h>
17#include <linux/string.h>
18#include <linux/list.h>
Alexey Dobriyane8edc6e2007-05-21 01:22:52 +040019#include <linux/sched.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070020
21#include <linux/coda.h>
22#include <linux/coda_linux.h>
23#include <linux/coda_psdev.h>
24#include <linux/coda_fs_i.h>
25#include <linux/coda_cache.h>
26
27static atomic_t permission_epoch = ATOMIC_INIT(0);
28
29/* replace or extend an acl cache hit */
30void coda_cache_enter(struct inode *inode, int mask)
31{
32 struct coda_inode_info *cii = ITOC(inode);
33
34 cii->c_cached_epoch = atomic_read(&permission_epoch);
35 if (cii->c_uid != current->fsuid) {
36 cii->c_uid = current->fsuid;
37 cii->c_cached_perm = mask;
38 } else
39 cii->c_cached_perm |= mask;
40}
41
42/* remove cached acl from an inode */
43void coda_cache_clear_inode(struct inode *inode)
44{
45 struct coda_inode_info *cii = ITOC(inode);
Jan Harkes56ee3542007-07-19 01:48:42 -070046 cii->c_cached_epoch = atomic_read(&permission_epoch) - 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -070047}
48
49/* remove all acl caches */
50void coda_cache_clear_all(struct super_block *sb)
51{
Linus Torvalds1da177e2005-04-16 15:20:36 -070052 atomic_inc(&permission_epoch);
53}
54
55
56/* check if the mask has been matched against the acl already */
57int coda_cache_check(struct inode *inode, int mask)
58{
59 struct coda_inode_info *cii = ITOC(inode);
60 int hit;
61
62 hit = (mask & cii->c_cached_perm) == mask &&
63 cii->c_uid == current->fsuid &&
64 cii->c_cached_epoch == atomic_read(&permission_epoch);
65
66 return hit;
67}
68
69
70/* Purging dentries and children */
71/* The following routines drop dentries which are not
72 in use and flag dentries which are in use to be
73 zapped later.
74
75 The flags are detected by:
76 - coda_dentry_revalidate (for lookups) if the flag is C_PURGE
77 - coda_dentry_delete: to remove dentry from the cache when d_count
78 falls to zero
79 - an inode method coda_revalidate (for attributes) if the
80 flag is C_VATTR
81*/
82
83/* this won't do any harm: just flag all children */
84static void coda_flag_children(struct dentry *parent, int flag)
85{
86 struct list_head *child;
87 struct dentry *de;
88
89 spin_lock(&dcache_lock);
90 list_for_each(child, &parent->d_subdirs)
91 {
Eric Dumazet5160ee6f2006-01-08 01:03:32 -080092 de = list_entry(child, struct dentry, d_u.d_child);
Linus Torvalds1da177e2005-04-16 15:20:36 -070093 /* don't know what to do with negative dentries */
94 if ( ! de->d_inode )
95 continue;
96 coda_flag_inode(de->d_inode, flag);
97 }
98 spin_unlock(&dcache_lock);
99 return;
100}
101
102void coda_flag_inode_children(struct inode *inode, int flag)
103{
104 struct dentry *alias_de;
105
106 if ( !inode || !S_ISDIR(inode->i_mode))
107 return;
108
109 alias_de = d_find_alias(inode);
110 if (!alias_de)
111 return;
112 coda_flag_children(alias_de, flag);
113 shrink_dcache_parent(alias_de);
114 dput(alias_de);
115}
116