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[PATCH] fuse: use jiffies_64

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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: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Miklos Szeredi 2006-07-30 03:04:10 -07:00 committed by Linus Torvalds
parent 685d16ddb0
commit 0a0898cf41
3 changed files with 38 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

44
fs/fuse/dir.c
View File

@ -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);

2
fs/fuse/fuse_i.h
View File

@ -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 */

2
fs/fuse/inode.c
View File

@ -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();