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