Commit 0a0898cf authored by Miklos Szeredi's avatar Miklos Szeredi Committed by Linus Torvalds
Browse files

[PATCH] fuse: use jiffies_64 



It is entirely possible (though rare) that jiffies half-wraps around, while a
dentry/inode remains in the cache.  This could mean that the dentry/inode is
not invalidated for another half wraparound-time.

To get around this problem, use 64-bit jiffies.  The only problem with this is
that dentry->d_time is 32 bits on 32-bit archs.  So use d_fsdata as the high
32 bits.  This is an ugly hack, but far simpler, than having to allocate
private data just for this purpose.

Since 64-bit jiffies can be assumed never to wrap around, simple comparison
can be used, and a zero time value can represent "invalid".

Signed-off-by: default avatarMiklos Szeredi <miklos@szeredi.hu>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 685d16dd

fs/fuse/dir.c

+36 −8
Original line number Diff line number Diff line
@@ -14,6 +14,33 @@ 
#include <linux/sched.h>

#include <linux/namei.h>



#if BITS_PER_LONG >= 64

static inline void fuse_dentry_settime(struct dentry *entry, u64 time)

{

	entry->d_time = time;

}



static inline u64 fuse_dentry_time(struct dentry *entry)

{

	return entry->d_time;

}

#else

/*

 * On 32 bit archs store the high 32 bits of time in d_fsdata

 */

static void fuse_dentry_settime(struct dentry *entry, u64 time)

{

	entry->d_time = time;

	entry->d_fsdata = (void *) (unsigned long) (time >> 32);

}



static u64 fuse_dentry_time(struct dentry *entry)

{

	return (u64) entry->d_time +

		((u64) (unsigned long) entry->d_fsdata << 32);

}

#endif



/*

 * FUSE caches dentries and attributes with separate timeout.  The

 * time in jiffies until the dentry/attributes are valid is stored in
@@ -23,13 +50,13 @@ 
/*

 * Calculate the time in jiffies until a dentry/attributes are valid

 */

static unsigned long time_to_jiffies(unsigned long sec, unsigned long nsec)

static u64 time_to_jiffies(unsigned long sec, unsigned long nsec)

{

	if (sec || nsec) {

		struct timespec ts = {sec, nsec};

		return jiffies + timespec_to_jiffies(&ts);

		return get_jiffies_64() + timespec_to_jiffies(&ts);

	} else

		return jiffies - 1;

		return 0;

}



/*
@@ -38,7 +65,8 @@ static unsigned long time_to_jiffies(unsigned long sec, unsigned long nsec) 
 */

static void fuse_change_timeout(struct dentry *entry, struct fuse_entry_out *o)

{

	entry->d_time = time_to_jiffies(o->entry_valid, o->entry_valid_nsec);

	fuse_dentry_settime(entry,

		time_to_jiffies(o->entry_valid, o->entry_valid_nsec));

	if (entry->d_inode)

		get_fuse_inode(entry->d_inode)->i_time =

			time_to_jiffies(o->attr_valid, o->attr_valid_nsec);
@@ -50,7 +78,7 @@ static void fuse_change_timeout(struct dentry *entry, struct fuse_entry_out *o) 
 */

void fuse_invalidate_attr(struct inode *inode)

{

	get_fuse_inode(inode)->i_time = jiffies - 1;

	get_fuse_inode(inode)->i_time = 0;

}



/*
@@ -63,7 +91,7 @@ void fuse_invalidate_attr(struct inode *inode) 
 */

static void fuse_invalidate_entry_cache(struct dentry *entry)

{

	entry->d_time = jiffies - 1;

	fuse_dentry_settime(entry, 0);

}



/*
@@ -105,7 +133,7 @@ static int fuse_dentry_revalidate(struct dentry *entry, struct nameidata *nd) 


	if (inode && is_bad_inode(inode))

		return 0;

	else if (time_after(jiffies, entry->d_time)) {

	else if (fuse_dentry_time(entry) < get_jiffies_64()) {

		int err;

		struct fuse_entry_out outarg;

		struct fuse_conn *fc;
@@ -669,7 +697,7 @@ static int fuse_revalidate(struct dentry *entry) 
	if (!fuse_allow_task(fc, current))

		return -EACCES;

	if (get_node_id(inode) != FUSE_ROOT_ID &&

	    time_before_eq(jiffies, fi->i_time))

	    fi->i_time >= get_jiffies_64())

		return 0;



	return fuse_do_getattr(inode);

fs/fuse/fuse_i.h

+1 −1
Original line number Diff line number Diff line
@@ -59,7 +59,7 @@ struct fuse_inode { 
	struct fuse_req *forget_req;



	/** Time in jiffies until the file attributes are valid */

	unsigned long i_time;

	u64 i_time;

};



/** FUSE specific file data */

fs/fuse/inode.c

+1 −1
Original line number Diff line number Diff line
@@ -51,7 +51,7 @@ static struct inode *fuse_alloc_inode(struct super_block *sb) 
		return NULL;



	fi = get_fuse_inode(inode);

	fi->i_time = jiffies - 1;

	fi->i_time = 0;

	fi->nodeid = 0;

	fi->nlookup = 0;

	fi->forget_req = fuse_request_alloc();

CRA Git | Maintained and supported by SUSTech CRA and CCSE