fs: change d_compare for rcu-walk
Change d_compare so it may be called from lock-free RCU lookups. This
does put significant restrictions on what may be done from the callback,
however there don't seem to have been any problems with in-tree fses.
If some strange use case pops up that _really_ cannot cope with the
rcu-walk rules, we can just add new rcu-unaware callbacks, which would
cause name lookup to drop out of rcu-walk mode.
For in-tree filesystems, this is just a mechanical change.
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
diff --git a/include/linux/dcache.h b/include/linux/dcache.h
index 6cdf499..75a072b 100644
--- a/include/linux/dcache.h
+++ b/include/linux/dcache.h
@@ -134,7 +134,9 @@
struct dentry_operations {
int (*d_revalidate)(struct dentry *, struct nameidata *);
int (*d_hash)(struct dentry *, struct qstr *);
- int (*d_compare)(struct dentry *, struct qstr *, struct qstr *);
+ int (*d_compare)(const struct dentry *, const struct inode *,
+ const struct dentry *, const struct inode *,
+ unsigned int, const char *, const struct qstr *);
int (*d_delete)(const struct dentry *);
void (*d_release)(struct dentry *);
void (*d_iput)(struct dentry *, struct inode *);
@@ -145,12 +147,8 @@
* Locking rules for dentry_operations callbacks are to be found in
* Documentation/filesystems/Locking. Keep it updated!
*
- * the dentry parameter passed to d_hash and d_compare is the parent
- * directory of the entries to be compared. It is used in case these
- * functions need any directory specific information for determining
- * equivalency classes. Using the dentry itself might not work, as it
- * might be a negative dentry which has no information associated with
- * it.
+ * FUrther descriptions are found in Documentation/filesystems/vfs.txt.
+ * Keep it updated too!
*/
/* d_flags entries */
