summaryrefslogtreecommitdiff
path: root/fs/fuse
diff options
context:
space:
mode:
authorTejun Heo <tj@kernel.org>2008-11-26 12:03:55 +0100
committerMiklos Szeredi <miklos@szeredi.hu>2008-11-26 12:03:55 +0100
commit95668a69a4bb862063c4d28a746e55107dee7b98 (patch)
tree0679e0f43274648bad70e694a9efb8bcfed55adc /fs/fuse
parent8599396b5062bf6bd2a0b433503849e2322df1c2 (diff)
downloadconfigs-95668a69a4bb862063c4d28a746e55107dee7b98.tar.gz
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>
Diffstat (limited to 'fs/fuse')
-rw-r--r--fs/fuse/dev.c19
-rw-r--r--fs/fuse/file.c132
-rw-r--r--fs/fuse/fuse_i.h20
-rw-r--r--fs/fuse/inode.c1
4 files changed, 172 insertions, 0 deletions
diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index ffd670bb8c8..6176e444c76 100644
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -816,10 +816,29 @@ static ssize_t fuse_dev_read(struct kiocb *iocb, const struct iovec *iov,
return err;
}
+static int fuse_notify_poll(struct fuse_conn *fc, unsigned int size,
+ struct fuse_copy_state *cs)
+{
+ struct fuse_notify_poll_wakeup_out outarg;
+ int err;
+
+ if (size != sizeof(outarg))
+ return -EINVAL;
+
+ err = fuse_copy_one(cs, &outarg, sizeof(outarg));
+ if (err)
+ return err;
+
+ return fuse_notify_poll_wakeup(fc, &outarg);
+}
+
static int fuse_notify(struct fuse_conn *fc, enum fuse_notify_code code,
unsigned int size, struct fuse_copy_state *cs)
{
switch (code) {
+ case FUSE_NOTIFY_POLL:
+ return fuse_notify_poll(fc, size, cs);
+
default:
return -EINVAL;
}
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index a28ced678d3..b3a944e4bb9 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -62,6 +62,8 @@ struct fuse_file *fuse_file_alloc(struct fuse_conn *fc)
ff->kh = ++fc->khctr;
spin_unlock(&fc->lock);
}
+ RB_CLEAR_NODE(&ff->polled_node);
+ init_waitqueue_head(&ff->poll_wait);
}
return ff;
}
@@ -170,7 +172,11 @@ int fuse_release_common(struct inode *inode, struct file *file, int isdir)
spin_lock(&fc->lock);
list_del(&ff->write_entry);
+ if (!RB_EMPTY_NODE(&ff->polled_node))
+ rb_erase(&ff->polled_node, &fc->polled_files);
spin_unlock(&fc->lock);
+
+ wake_up_interruptible_sync(&ff->poll_wait);
/*
* Normally this will send the RELEASE request,
* however if some asynchronous READ or WRITE requests
@@ -1749,6 +1755,130 @@ static long fuse_file_compat_ioctl(struct file *file, unsigned int cmd,
return fuse_file_do_ioctl(file, cmd, arg, FUSE_IOCTL_COMPAT);
}
+/*
+ * All files which have been polled are linked to RB tree
+ * fuse_conn->polled_files which is indexed by kh. Walk the tree and
+ * find the matching one.
+ */
+static struct rb_node **fuse_find_polled_node(struct fuse_conn *fc, u64 kh,
+ struct rb_node **parent_out)
+{
+ struct rb_node **link = &fc->polled_files.rb_node;
+ struct rb_node *last = NULL;
+
+ while (*link) {
+ struct fuse_file *ff;
+
+ last = *link;
+ ff = rb_entry(last, struct fuse_file, polled_node);
+
+ if (kh < ff->kh)
+ link = &last->rb_left;
+ else if (kh > ff->kh)
+ link = &last->rb_right;
+ else
+ return link;
+ }
+
+ if (parent_out)
+ *parent_out = last;
+ return link;
+}
+
+/*
+ * The file is about to be polled. Make sure it's on the polled_files
+ * RB tree. Note that files once added to the polled_files tree are
+ * not removed before the file is released. This is because a file
+ * polled once is likely to be polled again.
+ */
+static void fuse_register_polled_file(struct fuse_conn *fc,
+ struct fuse_file *ff)
+{
+ spin_lock(&fc->lock);
+ if (RB_EMPTY_NODE(&ff->polled_node)) {
+ struct rb_node **link, *parent;
+
+ link = fuse_find_polled_node(fc, ff->kh, &parent);
+ BUG_ON(*link);
+ rb_link_node(&ff->polled_node, parent, link);
+ rb_insert_color(&ff->polled_node, &fc->polled_files);
+ }
+ spin_unlock(&fc->lock);
+}
+
+static unsigned fuse_file_poll(struct file *file, poll_table *wait)
+{
+ struct inode *inode = file->f_dentry->d_inode;
+ struct fuse_file *ff = file->private_data;
+ struct fuse_conn *fc = get_fuse_conn(inode);
+ struct fuse_poll_in inarg = { .fh = ff->fh, .kh = ff->kh };
+ struct fuse_poll_out outarg;
+ struct fuse_req *req;
+ int err;
+
+ if (fc->no_poll)
+ return DEFAULT_POLLMASK;
+
+ poll_wait(file, &ff->poll_wait, wait);
+
+ /*
+ * Ask for notification iff there's someone waiting for it.
+ * The client may ignore the flag and always notify.
+ */
+ if (waitqueue_active(&ff->poll_wait)) {
+ inarg.flags |= FUSE_POLL_SCHEDULE_NOTIFY;
+ fuse_register_polled_file(fc, ff);
+ }
+
+ req = fuse_get_req(fc);
+ if (IS_ERR(req))
+ return PTR_ERR(req);
+
+ req->in.h.opcode = FUSE_POLL;
+ req->in.h.nodeid = get_node_id(inode);
+ req->in.numargs = 1;
+ req->in.args[0].size = sizeof(inarg);
+ req->in.args[0].value = &inarg;
+ req->out.numargs = 1;
+ req->out.args[0].size = sizeof(outarg);
+ req->out.args[0].value = &outarg;
+ request_send(fc, req);
+ err = req->out.h.error;
+ fuse_put_request(fc, req);
+
+ if (!err)
+ return outarg.revents;
+ if (err == -ENOSYS) {
+ fc->no_poll = 1;
+ return DEFAULT_POLLMASK;
+ }
+ return POLLERR;
+}
+
+/*
+ * This is called from fuse_handle_notify() on FUSE_NOTIFY_POLL and
+ * wakes up the poll waiters.
+ */
+int fuse_notify_poll_wakeup(struct fuse_conn *fc,
+ struct fuse_notify_poll_wakeup_out *outarg)
+{
+ u64 kh = outarg->kh;
+ struct rb_node **link;
+
+ spin_lock(&fc->lock);
+
+ link = fuse_find_polled_node(fc, kh, NULL);
+ if (*link) {
+ struct fuse_file *ff;
+
+ ff = rb_entry(*link, struct fuse_file, polled_node);
+ wake_up_interruptible_sync(&ff->poll_wait);
+ }
+
+ spin_unlock(&fc->lock);
+ return 0;
+}
+
static const struct file_operations fuse_file_operations = {
.llseek = fuse_file_llseek,
.read = do_sync_read,
@@ -1765,6 +1895,7 @@ static const struct file_operations fuse_file_operations = {
.splice_read = generic_file_splice_read,
.unlocked_ioctl = fuse_file_ioctl,
.compat_ioctl = fuse_file_compat_ioctl,
+ .poll = fuse_file_poll,
};
static const struct file_operations fuse_direct_io_file_operations = {
@@ -1779,6 +1910,7 @@ static const struct file_operations fuse_direct_io_file_operations = {
.flock = fuse_file_flock,
.unlocked_ioctl = fuse_file_ioctl,
.compat_ioctl = fuse_file_compat_ioctl,
+ .poll = fuse_file_poll,
/* no mmap and splice_read */
};
diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index 86f01330382..986fbd4c1ff 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 @@ struct fuse_file {
/** 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 @@ struct fuse_conn {
/** 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 @@ struct fuse_conn {
/** 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 fuse_fsync_common(struct file *file, struct dentry *de, int datasync,
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);
diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index 0e15bc221d2..ba725612808 100644
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -486,6 +486,7 @@ static struct fuse_conn *new_conn(struct super_block *sb)
/* fuse does it's own writeback accounting */
fc->bdi.capabilities = BDI_CAP_NO_ACCT_WB;
fc->khctr = 0;
+ fc->polled_files = RB_ROOT;
fc->dev = sb->s_dev;
err = bdi_init(&fc->bdi);
if (err)