File: /usr/src/linux/fs/coda/cache.c
1 /*
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/sched.h>
13 #include <linux/fs.h>
14 #include <linux/stat.h>
15 #include <linux/errno.h>
16 #include <linux/locks.h>
17 #include <asm/segment.h>
18 #include <asm/uaccess.h>
19 #include <linux/string.h>
20 #include <linux/list.h>
21
22 #include <linux/coda.h>
23 #include <linux/coda_linux.h>
24 #include <linux/coda_psdev.h>
25 #include <linux/coda_fs_i.h>
26 #include <linux/coda_cache.h>
27
28 /* replace or extend an acl cache hit */
29 void coda_cache_enter(struct inode *inode, int mask)
30 {
31 struct coda_inode_info *cii = ITOC(inode);
32 ENTRY;
33
34 if ( !coda_cred_ok(&cii->c_cached_cred) ) {
35 coda_load_creds(&cii->c_cached_cred);
36 cii->c_cached_perm = mask;
37 } else
38 cii->c_cached_perm |= mask;
39 }
40
41 /* remove cached acl from an inode */
42 void coda_cache_clear_inode(struct inode *inode)
43 {
44 struct coda_inode_info *cii = ITOC(inode);
45 ENTRY;
46 cii->c_cached_perm = 0;
47 }
48
49 /* remove all acl caches for a principal (or all principals when cred == NULL)*/
50 void coda_cache_clear_all(struct super_block *sb, struct coda_cred *cred)
51 {
52 struct coda_sb_info *sbi;
53 struct coda_inode_info *cii;
54 struct list_head *tmp;
55
56 ENTRY;
57 sbi = coda_sbp(sb);
58 if (!sbi) BUG();
59
60 list_for_each(tmp, &sbi->sbi_cihead)
61 {
62 cii = list_entry(tmp, struct coda_inode_info, c_cilist);
63 if (!cred || coda_cred_eq(cred, &cii->c_cached_cred))
64 cii->c_cached_perm = 0;
65 }
66 }
67
68
69 /* check if the mask has been matched against the acl already */
70 int coda_cache_check(struct inode *inode, int mask)
71 {
72 struct coda_inode_info *cii = ITOC(inode);
73 int hit;
74
75 hit = ((mask & cii->c_cached_perm) == mask) &&
76 coda_cred_ok(&cii->c_cached_cred);
77
78 CDEBUG(D_CACHE, "%s for ino %ld\n", hit ? "HIT" : "MISS", inode->i_ino);
79 return hit;
80 }
81
82
83 /* Purging dentries and children */
84 /* The following routines drop dentries which are not
85 in use and flag dentries which are in use to be
86 zapped later.
87
88 The flags are detected by:
89 - coda_dentry_revalidate (for lookups) if the flag is C_PURGE
90 - coda_dentry_delete: to remove dentry from the cache when d_count
91 falls to zero
92 - an inode method coda_revalidate (for attributes) if the
93 flag is C_VATTR
94 */
95
96 /* this won't do any harm: just flag all children */
97 static void coda_flag_children(struct dentry *parent, int flag)
98 {
99 struct list_head *child;
100 struct dentry *de;
101
102 spin_lock(&dcache_lock);
103 list_for_each(child, &parent->d_subdirs)
104 {
105 de = list_entry(child, struct dentry, d_child);
106 /* don't know what to do with negative dentries */
107 if ( ! de->d_inode )
108 continue;
109 CDEBUG(D_DOWNCALL, "%d for %*s/%*s\n", flag,
110 de->d_name.len, de->d_name.name,
111 de->d_parent->d_name.len, de->d_parent->d_name.name);
112 coda_flag_inode(de->d_inode, flag);
113 }
114 spin_unlock(&dcache_lock);
115 return;
116 }
117
118 void coda_flag_inode_children(struct inode *inode, int flag)
119 {
120 struct dentry *alias_de;
121
122 ENTRY;
123 if ( !inode || !S_ISDIR(inode->i_mode))
124 return;
125
126 alias_de = d_find_alias(inode);
127 if (!alias_de)
128 return;
129 coda_flag_children(alias_de, flag);
130 shrink_dcache_parent(alias_de);
131 dput(alias_de);
132 }
133
134