/* * 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/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_perm = 0;} /* remove all acl caches */void coda_cache_clear_all(struct super_block *sb){        struct coda_sb_info *sbi;         sbi = coda_sbp(sb);	BUG_ON(!sbi); 	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);}