Commit | Line | Data |
---|---|---|
1da177e4 LT |
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/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> | |
19 | ||
20 | #include <linux/coda.h> | |
21 | #include <linux/coda_linux.h> | |
22 | #include <linux/coda_psdev.h> | |
23 | #include <linux/coda_fs_i.h> | |
24 | #include <linux/coda_cache.h> | |
25 | ||
26 | static atomic_t permission_epoch = ATOMIC_INIT(0); | |
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 | ||
33 | cii->c_cached_epoch = atomic_read(&permission_epoch); | |
34 | if (cii->c_uid != current->fsuid) { | |
35 | cii->c_uid = current->fsuid; | |
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 | cii->c_cached_perm = 0; | |
46 | } | |
47 | ||
48 | /* remove all acl caches */ | |
49 | void coda_cache_clear_all(struct super_block *sb) | |
50 | { | |
51 | struct coda_sb_info *sbi; | |
52 | ||
53 | sbi = coda_sbp(sb); | |
54 | if (!sbi) BUG(); | |
55 | ||
56 | atomic_inc(&permission_epoch); | |
57 | } | |
58 | ||
59 | ||
60 | /* check if the mask has been matched against the acl already */ | |
61 | int coda_cache_check(struct inode *inode, int mask) | |
62 | { | |
63 | struct coda_inode_info *cii = ITOC(inode); | |
64 | int hit; | |
65 | ||
66 | hit = (mask & cii->c_cached_perm) == mask && | |
67 | cii->c_uid == current->fsuid && | |
68 | cii->c_cached_epoch == atomic_read(&permission_epoch); | |
69 | ||
70 | return hit; | |
71 | } | |
72 | ||
73 | ||
74 | /* Purging dentries and children */ | |
75 | /* The following routines drop dentries which are not | |
76 | in use and flag dentries which are in use to be | |
77 | zapped later. | |
78 | ||
79 | The flags are detected by: | |
80 | - coda_dentry_revalidate (for lookups) if the flag is C_PURGE | |
81 | - coda_dentry_delete: to remove dentry from the cache when d_count | |
82 | falls to zero | |
83 | - an inode method coda_revalidate (for attributes) if the | |
84 | flag is C_VATTR | |
85 | */ | |
86 | ||
87 | /* this won't do any harm: just flag all children */ | |
88 | static void coda_flag_children(struct dentry *parent, int flag) | |
89 | { | |
90 | struct list_head *child; | |
91 | struct dentry *de; | |
92 | ||
93 | spin_lock(&dcache_lock); | |
94 | list_for_each(child, &parent->d_subdirs) | |
95 | { | |
96 | de = list_entry(child, struct dentry, d_child); | |
97 | /* don't know what to do with negative dentries */ | |
98 | if ( ! de->d_inode ) | |
99 | continue; | |
100 | coda_flag_inode(de->d_inode, flag); | |
101 | } | |
102 | spin_unlock(&dcache_lock); | |
103 | return; | |
104 | } | |
105 | ||
106 | void coda_flag_inode_children(struct inode *inode, int flag) | |
107 | { | |
108 | struct dentry *alias_de; | |
109 | ||
110 | if ( !inode || !S_ISDIR(inode->i_mode)) | |
111 | return; | |
112 | ||
113 | alias_de = d_find_alias(inode); | |
114 | if (!alias_de) | |
115 | return; | |
116 | coda_flag_children(alias_de, flag); | |
117 | shrink_dcache_parent(alias_de); | |
118 | dput(alias_de); | |
119 | } | |
120 |