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
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>.
10 #include <linux/types.h>
11 #include <linux/kernel.h>
12 #include <linux/time.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 #include <linux/sched.h>
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>
27 static atomic_t permission_epoch
= ATOMIC_INIT(0);
29 /* replace or extend an acl cache hit */
30 void coda_cache_enter(struct inode
*inode
, int mask
)
32 struct coda_inode_info
*cii
= ITOC(inode
);
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
;
39 cii
->c_cached_perm
|= mask
;
42 /* remove cached acl from an inode */
43 void coda_cache_clear_inode(struct inode
*inode
)
45 struct coda_inode_info
*cii
= ITOC(inode
);
46 cii
->c_cached_perm
= 0;
49 /* remove all acl caches */
50 void coda_cache_clear_all(struct super_block
*sb
)
52 struct coda_sb_info
*sbi
;
57 atomic_inc(&permission_epoch
);
61 /* check if the mask has been matched against the acl already */
62 int coda_cache_check(struct inode
*inode
, int mask
)
64 struct coda_inode_info
*cii
= ITOC(inode
);
67 hit
= (mask
& cii
->c_cached_perm
) == mask
&&
68 cii
->c_uid
== current
->fsuid
&&
69 cii
->c_cached_epoch
== atomic_read(&permission_epoch
);
75 /* Purging dentries and children */
76 /* The following routines drop dentries which are not
77 in use and flag dentries which are in use to be
80 The flags are detected by:
81 - coda_dentry_revalidate (for lookups) if the flag is C_PURGE
82 - coda_dentry_delete: to remove dentry from the cache when d_count
84 - an inode method coda_revalidate (for attributes) if the
88 /* this won't do any harm: just flag all children */
89 static void coda_flag_children(struct dentry
*parent
, int flag
)
91 struct list_head
*child
;
94 spin_lock(&dcache_lock
);
95 list_for_each(child
, &parent
->d_subdirs
)
97 de
= list_entry(child
, struct dentry
, d_u
.d_child
);
98 /* don't know what to do with negative dentries */
101 coda_flag_inode(de
->d_inode
, flag
);
103 spin_unlock(&dcache_lock
);
107 void coda_flag_inode_children(struct inode
*inode
, int flag
)
109 struct dentry
*alias_de
;
111 if ( !inode
|| !S_ISDIR(inode
->i_mode
))
114 alias_de
= d_find_alias(inode
);
117 coda_flag_children(alias_de
, flag
);
118 shrink_dcache_parent(alias_de
);