1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun * Cache operations for Coda.
4*4882a593Smuzhiyun * For Linux 2.1: (C) 1997 Carnegie Mellon University
5*4882a593Smuzhiyun * For Linux 2.3: (C) 2000 Carnegie Mellon University
6*4882a593Smuzhiyun *
7*4882a593Smuzhiyun * Carnegie Mellon encourages users of this code to contribute improvements
8*4882a593Smuzhiyun * to the Coda project http://www.coda.cs.cmu.edu/ <coda@cs.cmu.edu>.
9*4882a593Smuzhiyun */
10*4882a593Smuzhiyun
11*4882a593Smuzhiyun #include <linux/types.h>
12*4882a593Smuzhiyun #include <linux/kernel.h>
13*4882a593Smuzhiyun #include <linux/time.h>
14*4882a593Smuzhiyun #include <linux/fs.h>
15*4882a593Smuzhiyun #include <linux/stat.h>
16*4882a593Smuzhiyun #include <linux/errno.h>
17*4882a593Smuzhiyun #include <linux/uaccess.h>
18*4882a593Smuzhiyun #include <linux/string.h>
19*4882a593Smuzhiyun #include <linux/list.h>
20*4882a593Smuzhiyun #include <linux/sched.h>
21*4882a593Smuzhiyun #include <linux/spinlock.h>
22*4882a593Smuzhiyun
23*4882a593Smuzhiyun #include <linux/coda.h>
24*4882a593Smuzhiyun #include "coda_psdev.h"
25*4882a593Smuzhiyun #include "coda_linux.h"
26*4882a593Smuzhiyun #include "coda_cache.h"
27*4882a593Smuzhiyun
28*4882a593Smuzhiyun static atomic_t permission_epoch = ATOMIC_INIT(0);
29*4882a593Smuzhiyun
30*4882a593Smuzhiyun /* replace or extend an acl cache hit */
coda_cache_enter(struct inode * inode,int mask)31*4882a593Smuzhiyun void coda_cache_enter(struct inode *inode, int mask)
32*4882a593Smuzhiyun {
33*4882a593Smuzhiyun struct coda_inode_info *cii = ITOC(inode);
34*4882a593Smuzhiyun
35*4882a593Smuzhiyun spin_lock(&cii->c_lock);
36*4882a593Smuzhiyun cii->c_cached_epoch = atomic_read(&permission_epoch);
37*4882a593Smuzhiyun if (!uid_eq(cii->c_uid, current_fsuid())) {
38*4882a593Smuzhiyun cii->c_uid = current_fsuid();
39*4882a593Smuzhiyun cii->c_cached_perm = mask;
40*4882a593Smuzhiyun } else
41*4882a593Smuzhiyun cii->c_cached_perm |= mask;
42*4882a593Smuzhiyun spin_unlock(&cii->c_lock);
43*4882a593Smuzhiyun }
44*4882a593Smuzhiyun
45*4882a593Smuzhiyun /* remove cached acl from an inode */
coda_cache_clear_inode(struct inode * inode)46*4882a593Smuzhiyun void coda_cache_clear_inode(struct inode *inode)
47*4882a593Smuzhiyun {
48*4882a593Smuzhiyun struct coda_inode_info *cii = ITOC(inode);
49*4882a593Smuzhiyun spin_lock(&cii->c_lock);
50*4882a593Smuzhiyun cii->c_cached_epoch = atomic_read(&permission_epoch) - 1;
51*4882a593Smuzhiyun spin_unlock(&cii->c_lock);
52*4882a593Smuzhiyun }
53*4882a593Smuzhiyun
54*4882a593Smuzhiyun /* remove all acl caches */
coda_cache_clear_all(struct super_block * sb)55*4882a593Smuzhiyun void coda_cache_clear_all(struct super_block *sb)
56*4882a593Smuzhiyun {
57*4882a593Smuzhiyun atomic_inc(&permission_epoch);
58*4882a593Smuzhiyun }
59*4882a593Smuzhiyun
60*4882a593Smuzhiyun
61*4882a593Smuzhiyun /* check if the mask has been matched against the acl already */
coda_cache_check(struct inode * inode,int mask)62*4882a593Smuzhiyun int coda_cache_check(struct inode *inode, int mask)
63*4882a593Smuzhiyun {
64*4882a593Smuzhiyun struct coda_inode_info *cii = ITOC(inode);
65*4882a593Smuzhiyun int hit;
66*4882a593Smuzhiyun
67*4882a593Smuzhiyun spin_lock(&cii->c_lock);
68*4882a593Smuzhiyun hit = (mask & cii->c_cached_perm) == mask &&
69*4882a593Smuzhiyun uid_eq(cii->c_uid, current_fsuid()) &&
70*4882a593Smuzhiyun cii->c_cached_epoch == atomic_read(&permission_epoch);
71*4882a593Smuzhiyun spin_unlock(&cii->c_lock);
72*4882a593Smuzhiyun
73*4882a593Smuzhiyun return hit;
74*4882a593Smuzhiyun }
75*4882a593Smuzhiyun
76*4882a593Smuzhiyun
77*4882a593Smuzhiyun /* Purging dentries and children */
78*4882a593Smuzhiyun /* The following routines drop dentries which are not
79*4882a593Smuzhiyun in use and flag dentries which are in use to be
80*4882a593Smuzhiyun zapped later.
81*4882a593Smuzhiyun
82*4882a593Smuzhiyun The flags are detected by:
83*4882a593Smuzhiyun - coda_dentry_revalidate (for lookups) if the flag is C_PURGE
84*4882a593Smuzhiyun - coda_dentry_delete: to remove dentry from the cache when d_count
85*4882a593Smuzhiyun falls to zero
86*4882a593Smuzhiyun - an inode method coda_revalidate (for attributes) if the
87*4882a593Smuzhiyun flag is C_VATTR
88*4882a593Smuzhiyun */
89*4882a593Smuzhiyun
90*4882a593Smuzhiyun /* this won't do any harm: just flag all children */
coda_flag_children(struct dentry * parent,int flag)91*4882a593Smuzhiyun static void coda_flag_children(struct dentry *parent, int flag)
92*4882a593Smuzhiyun {
93*4882a593Smuzhiyun struct dentry *de;
94*4882a593Smuzhiyun
95*4882a593Smuzhiyun spin_lock(&parent->d_lock);
96*4882a593Smuzhiyun list_for_each_entry(de, &parent->d_subdirs, d_child) {
97*4882a593Smuzhiyun /* don't know what to do with negative dentries */
98*4882a593Smuzhiyun if (d_inode(de) )
99*4882a593Smuzhiyun coda_flag_inode(d_inode(de), flag);
100*4882a593Smuzhiyun }
101*4882a593Smuzhiyun spin_unlock(&parent->d_lock);
102*4882a593Smuzhiyun return;
103*4882a593Smuzhiyun }
104*4882a593Smuzhiyun
coda_flag_inode_children(struct inode * inode,int flag)105*4882a593Smuzhiyun void coda_flag_inode_children(struct inode *inode, int flag)
106*4882a593Smuzhiyun {
107*4882a593Smuzhiyun struct dentry *alias_de;
108*4882a593Smuzhiyun
109*4882a593Smuzhiyun if ( !inode || !S_ISDIR(inode->i_mode))
110*4882a593Smuzhiyun return;
111*4882a593Smuzhiyun
112*4882a593Smuzhiyun alias_de = d_find_alias(inode);
113*4882a593Smuzhiyun if (!alias_de)
114*4882a593Smuzhiyun return;
115*4882a593Smuzhiyun coda_flag_children(alias_de, flag);
116*4882a593Smuzhiyun shrink_dcache_parent(alias_de);
117*4882a593Smuzhiyun dput(alias_de);
118*4882a593Smuzhiyun }
119*4882a593Smuzhiyun
120