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/*
* Cache operations for Coda.
* For Linux 2.1: (C) 1997 Carnegie Mellon University
*
* Carnegie Mellon encourages users of this code to contribute improvements
* to the Coda project. Contact Peter Braam <coda@cs.cmu.edu>.
*/
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/fs.h>
#include <linux/stat.h>
#include <linux/errno.h>
#include <linux/locks.h>
#include <asm/segment.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>
/* replace or extend an acl cache hit */
void coda_cache_enter(struct inode *inode, int mask)
{
struct coda_inode_info *cii = ITOC(inode);
ENTRY;
if ( !coda_cred_ok(&cii->c_cached_cred) ) {
coda_load_creds(&cii->c_cached_cred);
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);
ENTRY;
cii->c_cached_perm = 0;
}
/* remove all acl caches for a principal (or all principals when cred == NULL)*/
void coda_cache_clear_all(struct super_block *sb, struct coda_cred *cred)
{
struct coda_sb_info *sbi;
struct coda_inode_info *cii;
struct list_head *tmp;
ENTRY;
sbi = coda_sbp(sb);
if (!sbi) BUG();
list_for_each(tmp, &sbi->sbi_cihead)
{
cii = list_entry(tmp, struct coda_inode_info, c_cilist);
if ( cii->c_magic != CODA_CNODE_MAGIC ) BUG();
if (!cred || coda_cred_eq(cred, &cii->c_cached_cred))
cii->c_cached_perm = 0;
}
}
/* 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) &&
coda_cred_ok(&cii->c_cached_cred);
CDEBUG(D_CACHE, "%s for ino %ld\n", hit ? "HIT" : "MISS", inode->i_ino);
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
*/
/*
Some of this is pretty scary: what can disappear underneath us?
- shrink_dcache_parent calls on purge_one_dentry which is safe:
it only purges children.
- dput is evil since it may recurse up the dentry tree
*/
void coda_purge_dentries(struct inode *inode)
{
if (!inode)
return ;
/* better safe than sorry: dput could kill us */
iget(inode->i_sb, inode->i_ino);
/* catch the dentries later if some are still busy */
coda_flag_inode(inode, C_PURGE);
d_prune_aliases(inode);
iput(inode);
}
/* 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_child);
/* don't know what to do with negative dentries */
if ( ! de->d_inode )
continue;
CDEBUG(D_DOWNCALL, "%d for %*s/%*s\n", flag,
de->d_name.len, de->d_name.name,
de->d_parent->d_name.len, de->d_parent->d_name.name);
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;
ENTRY;
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);
}
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