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authorJeff Dike <jdike@addtoit.com>2006-04-10 22:54:52 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2006-04-11 06:18:48 -0700
commit385a17bfc3cb035333c8a91eddc78a6e04c4625e (patch)
tree7a9fde77c95f0e4cc86f31e8b1f5d23b6d815634
parent7025d9ad10a38dadef8b286e0092731c2d3cdc53 (diff)
downloadop-kernel-dev-385a17bfc3cb035333c8a91eddc78a6e04c4625e.zip
op-kernel-dev-385a17bfc3cb035333c8a91eddc78a6e04c4625e.tar.gz
[PATCH] fuse: add O_ASYNC support to FUSE device
This adds asynchronous notification to FUSE - a FUSE server can request O_ASYNC on a /dev/fuse file descriptor and receive SIGIO when there is input available. One subtlety - fuse_dev_fasync, which is called when O_ASYNC is requested, does no locking, unlink the other methods. I think it's unnecessary, as the fuse_conn.fasync list is manipulated only by fasync_helper and kill_fasync, which provide their own locking. It would also be wrong to use the fuse_lock, as it's a spin lock and fasync_helper can sleep. My one concern with this is the fuse_conn going away underneath fuse_dev_fasync - sys_fcntl takes a reference on the file struct, so this seems not to be a problem. Signed-off-by: Jeff Dike <jdike@addtoit.com> Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
-rw-r--r--fs/fuse/dev.c17
-rw-r--r--fs/fuse/fuse_i.h3
-rw-r--r--fs/fuse/inode.c1
3 files changed, 20 insertions, 1 deletions
diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index b2e8613..438770f 100644
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -317,6 +317,7 @@ static void queue_request(struct fuse_conn *fc, struct fuse_req *req)
list_add_tail(&req->list, &fc->pending);
req->state = FUSE_REQ_PENDING;
wake_up(&fc->waitq);
+ kill_fasync(&fc->fasync, SIGIO, POLL_IN);
}
/*
@@ -901,6 +902,7 @@ void fuse_abort_conn(struct fuse_conn *fc)
end_requests(fc, &fc->pending);
end_requests(fc, &fc->processing);
wake_up_all(&fc->waitq);
+ kill_fasync(&fc->fasync, SIGIO, POLL_IN);
}
spin_unlock(&fuse_lock);
}
@@ -917,12 +919,24 @@ static int fuse_dev_release(struct inode *inode, struct file *file)
end_requests(fc, &fc->processing);
}
spin_unlock(&fuse_lock);
- if (fc)
+ if (fc) {
+ fasync_helper(-1, file, 0, &fc->fasync);
kobject_put(&fc->kobj);
+ }
return 0;
}
+static int fuse_dev_fasync(int fd, struct file *file, int on)
+{
+ struct fuse_conn *fc = fuse_get_conn(file);
+ if (!fc)
+ return -ENODEV;
+
+ /* No locking - fasync_helper does its own locking */
+ return fasync_helper(fd, file, on, &fc->fasync);
+}
+
const struct file_operations fuse_dev_operations = {
.owner = THIS_MODULE,
.llseek = no_llseek,
@@ -932,6 +946,7 @@ const struct file_operations fuse_dev_operations = {
.writev = fuse_dev_writev,
.poll = fuse_dev_poll,
.release = fuse_dev_release,
+ .fasync = fuse_dev_fasync,
};
static struct miscdevice fuse_miscdevice = {
diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index a16a04f..e5cb46b 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -318,6 +318,9 @@ struct fuse_conn {
/** kobject */
struct kobject kobj;
+
+ /** O_ASYNC requests */
+ struct fasync_struct *fasync;
};
static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb)
diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index 879e6fb..78700cb 100644
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -216,6 +216,7 @@ static void fuse_put_super(struct super_block *sb)
spin_unlock(&fuse_lock);
up_write(&fc->sbput_sem);
/* Flush all readers on this fs */
+ kill_fasync(&fc->fasync, SIGIO, POLL_IN);
wake_up_all(&fc->waitq);
kobject_del(&fc->kobj);
kobject_put(&fc->kobj);
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