[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: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index 6db66ec..409ce6a 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -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 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 @@
*/
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 @@
*/
static void fuse_invalidate_entry_cache(struct dentry *entry)
{
- entry->d_time = jiffies - 1;
+ fuse_dentry_settime(entry, 0);
}
/*
@@ -105,7 +133,7 @@
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 @@
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);