Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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> |
Alexey Dobriyan | e8edc6e | 2007-05-21 01:22:52 +0400 | [diff] [blame] | 19 | #include <linux/sched.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 20 | |
| 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 | |
| 27 | static atomic_t permission_epoch = ATOMIC_INIT(0); |
| 28 | |
| 29 | /* replace or extend an acl cache hit */ |
| 30 | void 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 */ |
| 43 | void coda_cache_clear_inode(struct inode *inode) |
| 44 | { |
| 45 | struct coda_inode_info *cii = ITOC(inode); |
Jan Harkes | 56ee354 | 2007-07-19 01:48:42 -0700 | [diff] [blame] | 46 | cii->c_cached_epoch = atomic_read(&permission_epoch) - 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 47 | } |
| 48 | |
| 49 | /* remove all acl caches */ |
| 50 | void coda_cache_clear_all(struct super_block *sb) |
| 51 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 52 | atomic_inc(&permission_epoch); |
| 53 | } |
| 54 | |
| 55 | |
| 56 | /* check if the mask has been matched against the acl already */ |
| 57 | int 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 */ |
| 84 | static 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 Dumazet | 5160ee6f | 2006-01-08 01:03:32 -0800 | [diff] [blame] | 92 | de = list_entry(child, struct dentry, d_u.d_child); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 93 | /* 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 | |
| 102 | void 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 | |