fuse: invalidation reverse calls
Add notification messages that allow the filesystem to invalidate VFS
caches.
Two notifications are added:
1) inode invalidation
- invalidate cached attributes
- invalidate a range of pages in the page cache (this is optional)
2) dentry invalidation
- try to invalidate a subtree in the dentry cache
Care must be taken while accessing the 'struct super_block' for the
mount, as it can go away while an invalidation is in progress. To
prevent this, introduce a rw-semaphore, that is taken for read during
the invalidation and taken for write in the ->kill_sb callback.
Cc: Csaba Henk <csaba@gluster.com>
Cc: Anand Avati <avati@zresearch.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index 6b70073..e703654 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -859,6 +859,43 @@
return err;
}
+int fuse_reverse_inval_entry(struct super_block *sb, u64 parent_nodeid,
+ struct qstr *name)
+{
+ int err = -ENOTDIR;
+ struct inode *parent;
+ struct dentry *dir;
+ struct dentry *entry;
+
+ parent = ilookup5(sb, parent_nodeid, fuse_inode_eq, &parent_nodeid);
+ if (!parent)
+ return -ENOENT;
+
+ mutex_lock(&parent->i_mutex);
+ if (!S_ISDIR(parent->i_mode))
+ goto unlock;
+
+ err = -ENOENT;
+ dir = d_find_alias(parent);
+ if (!dir)
+ goto unlock;
+
+ entry = d_lookup(dir, name);
+ dput(dir);
+ if (!entry)
+ goto unlock;
+
+ fuse_invalidate_attr(parent);
+ fuse_invalidate_entry(entry);
+ dput(entry);
+ err = 0;
+
+ unlock:
+ mutex_unlock(&parent->i_mutex);
+ iput(parent);
+ return err;
+}
+
/*
* Calling into a user-controlled filesystem gives the filesystem
* daemon ptrace-like capabilities over the requester process. This
