/* * 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 <asm/uaccess.h> #include <linux/string.h> #include <linux/list.h> #include <linux/sched.h> #include <linux/coda.h> #include <linux/coda_linux.h> #include <linux/coda_psdev.h> #include <linux/coda_fs_i.h> #include <linux/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); cii->c_cached_epoch = atomic_read(&permission_epoch); if (cii->c_uid != current->fsuid) { cii->c_uid = current->fsuid; cii->c_cached_perm = mask; } else cii->c_cached_perm |= mask; } /* remove cached acl from an inode */ void coda_cache_clear_inode(struct inode *inode) { struct coda_inode_info *cii = ITOC(inode); cii->c_cached_epoch = atomic_read(&permission_epoch) - 1; } /* 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; hit = (mask & cii->c_cached_perm) == mask && cii->c_uid == current->fsuid && cii->c_cached_epoch == atomic_read(&permission_epoch); 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 list_head *child; struct dentry *de; spin_lock(&dcache_lock); list_for_each(child, &parent->d_subdirs) { de = list_entry(child, struct dentry, d_u.d_child); /* don't know what to do with negative dentries */ if ( ! de->d_inode ) continue; coda_flag_inode(de->d_inode, flag); } spin_unlock(&dcache_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); }