[mirror_ubuntu-artful-kernel.git] / fs / coda / cache.c

/*
 * 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/spinlock.h>

#include <linux/coda.h>
#include <linux/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 (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 &&
	    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 list_head *child;
	struct dentry *de;

	spin_lock(&parent->d_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(&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);
}
Commit	Line	Data
1da177e4 LT	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>
e8edc6e0	19	#include <linux/sched.h>
b5ce1d83	20	#include <linux/spinlock.h>
1da177e4 LT	21
1da177e4 LT	22	#include <linux/coda.h>
1da177e4	23	#include <linux/coda_psdev.h>
31a203df AV	24	#include "coda_linux.h"
31a203df AV	25	#include "coda_cache.h"
1da177e4 LT	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
b5ce1d83	34	spin_lock(&cii->c_lock);
1da177e4	35	cii->c_cached_epoch = atomic_read(&permission_epoch);
97b7702c DH	36	if (cii->c_uid != current_fsuid()) {
97b7702c DH	37	cii->c_uid = current_fsuid();
1da177e4 LT	38	cii->c_cached_perm = mask;
	39	} else
	40	cii->c_cached_perm \|= mask;
b5ce1d83	41	spin_unlock(&cii->c_lock);
1da177e4 LT	42	}
	43
	44	/* remove cached acl from an inode */
	45	void coda_cache_clear_inode(struct inode *inode)
	46	{
	47	struct coda_inode_info *cii = ITOC(inode);
b5ce1d83	48	spin_lock(&cii->c_lock);
56ee3547	49	cii->c_cached_epoch = atomic_read(&permission_epoch) - 1;
b5ce1d83	50	spin_unlock(&cii->c_lock);
1da177e4 LT	51	}
	52
	53	/* remove all acl caches */
	54	void coda_cache_clear_all(struct super_block *sb)
	55	{
1da177e4 LT	56	atomic_inc(&permission_epoch);
	57	}
	58
	59
	60	/* check if the mask has been matched against the acl already */
	61	int coda_cache_check(struct inode *inode, int mask)
	62	{
	63	struct coda_inode_info *cii = ITOC(inode);
b5ce1d83	64	int hit;
1da177e4	65
b5ce1d83 YA	66	spin_lock(&cii->c_lock);
	67	hit = (mask & cii->c_cached_perm) == mask &&
	68	cii->c_uid == current_fsuid() &&
	69	cii->c_cached_epoch == atomic_read(&permission_epoch);
	70	spin_unlock(&cii->c_lock);
1da177e4	71
b5ce1d83	72	return hit;
1da177e4 LT	73	}
	74
	75
	76	/* Purging dentries and children */
	77	/* The following routines drop dentries which are not
	78	in use and flag dentries which are in use to be
	79	zapped later.
	80
	81	The flags are detected by:
	82	- coda_dentry_revalidate (for lookups) if the flag is C_PURGE
	83	- coda_dentry_delete: to remove dentry from the cache when d_count
	84	falls to zero
	85	- an inode method coda_revalidate (for attributes) if the
	86	flag is C_VATTR
	87	*/
	88
	89	/* this won't do any harm: just flag all children */
	90	static void coda_flag_children(struct dentry *parent, int flag)
	91	{
	92	struct list_head *child;
	93	struct dentry *de;
	94
2fd6b7f5	95	spin_lock(&parent->d_lock);
1da177e4 LT	96	list_for_each(child, &parent->d_subdirs)
1da177e4 LT	97	{
5160ee6f	98	de = list_entry(child, struct dentry, d_u.d_child);
1da177e4 LT	99	/* don't know what to do with negative dentries */
	100	if ( ! de->d_inode )
	101	continue;
	102	coda_flag_inode(de->d_inode, flag);
	103	}
2fd6b7f5	104	spin_unlock(&parent->d_lock);
1da177e4 LT	105	return;
	106	}
	107
	108	void coda_flag_inode_children(struct inode *inode, int flag)
	109	{
	110	struct dentry *alias_de;
	111
	112	if ( !inode \|\| !S_ISDIR(inode->i_mode))
	113	return;
	114
	115	alias_de = d_find_alias(inode);
	116	if (!alias_de)
	117	return;
	118	coda_flag_children(alias_de, flag);
	119	shrink_dcache_parent(alias_de);
	120	dput(alias_de);
	121	}
	122