fuse: implement NFS-like readdirplus support
This patch implements readdirplus support in FUSE, similar to NFS.
The payload returned in the readdirplus call contains
'fuse_entry_out' structure thereby providing all the necessary inputs
for 'faking' a lookup() operation on the spot.
If the dentry and inode already existed (for e.g. in a re-run of ls -l)
then just the inode attributes timeout and dentry timeout are refreshed.
With a simple client->network->server implementation of a FUSE based
filesystem, the following performance observations were made:
Test: Performing a filesystem crawl over 20,000 files with
sh# time ls -lR /mnt
Without readdirplus:
Run 1: 18.1s
Run 2: 16.0s
Run 3: 16.2s
With readdirplus:
Run 1: 4.1s
Run 2: 3.8s
Run 3: 3.8s
The performance improvement is significant as it avoided 20,000 upcalls
calls (lookup). Cache consistency is no worse than what already is.
Signed-off-by: Anand V. Avati <avati@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
diff --git a/include/uapi/linux/fuse.h b/include/uapi/linux/fuse.h
index d8c713e..5dc1fea 100644
--- a/include/uapi/linux/fuse.h
+++ b/include/uapi/linux/fuse.h
@@ -193,6 +193,7 @@
#define FUSE_FLOCK_LOCKS (1 << 10)
#define FUSE_HAS_IOCTL_DIR (1 << 11)
#define FUSE_AUTO_INVAL_DATA (1 << 12)
+#define FUSE_DO_READDIRPLUS (1 << 13)
/**
* CUSE INIT request/reply flags
@@ -299,6 +300,7 @@
FUSE_NOTIFY_REPLY = 41,
FUSE_BATCH_FORGET = 42,
FUSE_FALLOCATE = 43,
+ FUSE_READDIRPLUS = 44,
/* CUSE specific operations */
CUSE_INIT = 4096,
@@ -630,6 +632,16 @@
#define FUSE_DIRENT_SIZE(d) \
FUSE_DIRENT_ALIGN(FUSE_NAME_OFFSET + (d)->namelen)
+struct fuse_direntplus {
+ struct fuse_entry_out entry_out;
+ struct fuse_dirent dirent;
+};
+
+#define FUSE_NAME_OFFSET_DIRENTPLUS \
+ offsetof(struct fuse_direntplus, dirent.name)
+#define FUSE_DIRENTPLUS_SIZE(d) \
+ FUSE_DIRENT_ALIGN(FUSE_NAME_OFFSET_DIRENTPLUS + (d)->dirent.namelen)
+
struct fuse_notify_inval_inode_out {
__u64 ino;
__s64 off;