fuse: implement poll support
Implement poll support. Polled files are indexed using kh in a RB
tree rooted at fuse_conn->polled_files.
Client should send FUSE_NOTIFY_POLL notification once after processing
FUSE_POLL which has FUSE_POLL_SCHEDULE_NOTIFY set. Sending
notification unconditionally after the latest poll or everytime file
content might have changed is inefficient but won't cause malfunction.
fuse_file_poll() can sleep and requires patches from the following
thread which allows f_op->poll() to sleep.
http://thread.gmane.org/gmane.linux.kernel/726176
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index 86f0133..986fbd4 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -19,6 +19,8 @@
#include <linux/backing-dev.h>
#include <linux/mutex.h>
#include <linux/rwsem.h>
+#include <linux/rbtree.h>
+#include <linux/poll.h>
/** Max number of pages that can be used in a single read request */
#define FUSE_MAX_PAGES_PER_REQ 32
@@ -111,6 +113,12 @@
/** Entry on inode's write_files list */
struct list_head write_entry;
+
+ /** RB node to be linked on fuse_conn->polled_files */
+ struct rb_node polled_node;
+
+ /** Wait queue head for poll */
+ wait_queue_head_t poll_wait;
};
/** One input argument of a request */
@@ -328,6 +336,9 @@
/** The next unique kernel file handle */
u64 khctr;
+ /** rbtree of fuse_files waiting for poll events indexed by ph */
+ struct rb_root polled_files;
+
/** Number of requests currently in the background */
unsigned num_background;
@@ -416,6 +427,9 @@
/** Is bmap not implemented by fs? */
unsigned no_bmap:1;
+ /** Is poll not implemented by fs? */
+ unsigned no_poll:1;
+
/** Do multi-page cached writes */
unsigned big_writes:1;
@@ -525,6 +539,12 @@
int isdir);
/**
+ * Notify poll wakeup
+ */
+int fuse_notify_poll_wakeup(struct fuse_conn *fc,
+ struct fuse_notify_poll_wakeup_out *outarg);
+
+/**
* Initialize file operations on a regular file
*/
void fuse_init_file_inode(struct inode *inode);