fuse: allow control of adaptive readdirplus use

For some filesystems (e.g. GlusterFS), the cost of performing a
normal readdir and readdirplus are identical.  Since adaptively
using readdirplus has no benefit for those systems, give
users/filesystems the option to control adaptive readdirplus use.

v2 of this patch incorporates Miklos's suggestion to simplify the code,
as well as improving consistency of macro names and documentation.

Signed-off-by: Eric Wong <normalperson@yhbt.net>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>

diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index 2b112d9..8506522 100644 (file)
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -21,6 +21,8 @@ static bool fuse_use_readdirplus(struct inode *dir, struct file *filp)
 
        if (!fc->do_readdirplus)
                return false;
+       if (!fc->readdirplus_auto)
+               return true;
        if (test_and_clear_bit(FUSE_I_ADVISE_RDPLUS, &fi->state))
                return true;
        if (filp->f_pos == 0)

diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index fc55dd3..6aeba86 100644 (file)
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -514,9 +514,12 @@ struct fuse_conn {
        /** Use enhanced/automatic page cache invalidation. */
        unsigned auto_inval_data:1;
 
-       /** Does the filesystem support readdir-plus? */
+       /** Does the filesystem support readdirplus? */
        unsigned do_readdirplus:1;
 
+       /** Does the filesystem want adaptive readdirplus? */
+       unsigned readdirplus_auto:1;
+
        /** The number of requests waiting for completion */
        atomic_t num_waiting;
 

diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index 9876a87..01353ed 100644 (file)
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -866,6 +866,8 @@ static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req)
                                fc->auto_inval_data = 1;
                        if (arg->flags & FUSE_DO_READDIRPLUS)
                                fc->do_readdirplus = 1;
+                       if (arg->flags & FUSE_READDIRPLUS_AUTO)
+                               fc->readdirplus_auto = 1;
                } else {
                        ra_pages = fc->max_read / PAGE_CACHE_SIZE;
                        fc->no_lock = 1;
@@ -893,7 +895,7 @@ static void fuse_send_init(struct fuse_conn *fc, struct fuse_req *req)
                FUSE_EXPORT_SUPPORT | FUSE_BIG_WRITES | FUSE_DONT_MASK |
                FUSE_SPLICE_WRITE | FUSE_SPLICE_MOVE | FUSE_SPLICE_READ |
                FUSE_FLOCK_LOCKS | FUSE_IOCTL_DIR | FUSE_AUTO_INVAL_DATA |
-               FUSE_DO_READDIRPLUS;
+               FUSE_DO_READDIRPLUS | FUSE_READDIRPLUS_AUTO;
        req->in.h.opcode = FUSE_INIT;
        req->in.numargs = 1;
        req->in.args[0].size = sizeof(*arg);

diff --git a/include/uapi/linux/fuse.h b/include/uapi/linux/fuse.h
index baee03e..4c43b44 100644 (file)
--- a/include/uapi/linux/fuse.h
+++ b/include/uapi/linux/fuse.h
@@ -218,6 +218,8 @@ struct fuse_file_lock {
  * FUSE_FLOCK_LOCKS: remote locking for BSD style file locks
  * FUSE_HAS_IOCTL_DIR: kernel supports ioctl on directories
  * FUSE_AUTO_INVAL_DATA: automatically invalidate cached pages
+ * FUSE_DO_READDIRPLUS: do READDIRPLUS (READDIR+LOOKUP in one)
+ * FUSE_READDIRPLUS_AUTO: adaptive readdirplus
  */
 #define FUSE_ASYNC_READ                (1 << 0)
 #define FUSE_POSIX_LOCKS       (1 << 1)
@@ -233,6 +235,7 @@ struct fuse_file_lock {
 #define FUSE_HAS_IOCTL_DIR     (1 << 11)
 #define FUSE_AUTO_INVAL_DATA   (1 << 12)
 #define FUSE_DO_READDIRPLUS    (1 << 13)
+#define FUSE_READDIRPLUS_AUTO  (1 << 14)
 
 /**
  * CUSE INIT request/reply flags