From 5a5fb1ea74d8b82ca1461b885a1334fb21e037be Mon Sep 17 00:00:00 2001 From: Miklos Szeredi Date: Wed, 26 Apr 2006 10:48:55 +0200 Subject: Revert "[fuse] fix deadlock between fuse_put_super() and request_end()" This reverts 73ce8355c243a434524a34c05cc417dd0467996e commit. It was wrong, because it didn't take into account the requirement, that iput() for background requests must be performed synchronously with ->put_super(), otherwise active inodes may remain after unmount. The right solution is to keep the sbput_sem and perform iput() within the locked region, but move fput() outside sbput_sem. Signed-off-by: Miklos Szeredi --- fs/fuse/dev.c | 28 ++++++++++++---------------- fs/fuse/fuse_i.h | 12 +++++++++--- fs/fuse/inode.c | 27 ++++++++++----------------- 3 files changed, 31 insertions(+), 36 deletions(-) (limited to 'fs/fuse') diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c index cc750c68fe70..4967bd40b953 100644 --- a/fs/fuse/dev.c +++ b/fs/fuse/dev.c @@ -128,14 +128,20 @@ void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req) } } -void fuse_remove_background(struct fuse_conn *fc, struct fuse_req *req) +void fuse_release_background(struct fuse_conn *fc, struct fuse_req *req) { - list_del_init(&req->bg_entry); + iput(req->inode); + iput(req->inode2); + if (req->file) + fput(req->file); + spin_lock(&fc->lock); + list_del(&req->bg_entry); if (fc->num_background == FUSE_MAX_BACKGROUND) { fc->blocked = 0; wake_up_all(&fc->blocked_waitq); } fc->num_background--; + spin_unlock(&fc->lock); } /* @@ -165,27 +171,17 @@ static void request_end(struct fuse_conn *fc, struct fuse_req *req) wake_up(&req->waitq); fuse_put_request(fc, req); } else { - struct inode *inode = req->inode; - struct inode *inode2 = req->inode2; - struct file *file = req->file; void (*end) (struct fuse_conn *, struct fuse_req *) = req->end; req->end = NULL; - req->inode = NULL; - req->inode2 = NULL; - req->file = NULL; - if (!list_empty(&req->bg_entry)) - fuse_remove_background(fc, req); spin_unlock(&fc->lock); - + down_read(&fc->sbput_sem); + if (fc->mounted) + fuse_release_background(fc, req); + up_read(&fc->sbput_sem); if (end) end(fc, req); else fuse_put_request(fc, req); - - if (file) - fput(file); - iput(inode); - iput(inode2); } } diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h index 59661c481d9d..0474202cb5dc 100644 --- a/fs/fuse/fuse_i.h +++ b/fs/fuse/fuse_i.h @@ -258,9 +258,15 @@ struct fuse_conn { /** waitq for blocked connection */ wait_queue_head_t blocked_waitq; + /** RW semaphore for exclusion with fuse_put_super() */ + struct rw_semaphore sbput_sem; + /** The next unique request id */ u64 reqctr; + /** Mount is active */ + unsigned mounted; + /** Connection established, cleared on umount, connection abort and device release */ unsigned connected; @@ -471,11 +477,11 @@ void request_send_noreply(struct fuse_conn *fc, struct fuse_req *req); void request_send_background(struct fuse_conn *fc, struct fuse_req *req); /** - * Remove request from the the background list + * Release inodes and file associated with background request */ -void fuse_remove_background(struct fuse_conn *fc, struct fuse_req *req); +void fuse_release_background(struct fuse_conn *fc, struct fuse_req *req); -/** Abort all requests */ +/* Abort all requests */ void fuse_abort_conn(struct fuse_conn *fc); /** diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c index 43a6fc0db8a7..fd34037b0588 100644 --- a/fs/fuse/inode.c +++ b/fs/fuse/inode.c @@ -204,26 +204,17 @@ static void fuse_put_super(struct super_block *sb) { struct fuse_conn *fc = get_fuse_conn_super(sb); + down_write(&fc->sbput_sem); + while (!list_empty(&fc->background)) + fuse_release_background(fc, + list_entry(fc->background.next, + struct fuse_req, bg_entry)); + spin_lock(&fc->lock); + fc->mounted = 0; fc->connected = 0; - while (!list_empty(&fc->background)) { - struct fuse_req *req = list_entry(fc->background.next, - struct fuse_req, bg_entry); - struct inode *inode = req->inode; - struct inode *inode2 = req->inode2; - - /* File would hold a reference to vfsmount */ - BUG_ON(req->file); - req->inode = NULL; - req->inode2 = NULL; - fuse_remove_background(fc, req); - - spin_unlock(&fc->lock); - iput(inode); - iput(inode2); - spin_lock(&fc->lock); - } spin_unlock(&fc->lock); + up_write(&fc->sbput_sem); /* Flush all readers on this fs */ kill_fasync(&fc->fasync, SIGIO, POLL_IN); wake_up_all(&fc->waitq); @@ -395,6 +386,7 @@ static struct fuse_conn *new_conn(void) INIT_LIST_HEAD(&fc->processing); INIT_LIST_HEAD(&fc->io); INIT_LIST_HEAD(&fc->background); + init_rwsem(&fc->sbput_sem); kobj_set_kset_s(fc, connections_subsys); kobject_init(&fc->kobj); atomic_set(&fc->num_waiting, 0); @@ -549,6 +541,7 @@ static int fuse_fill_super(struct super_block *sb, void *data, int silent) goto err_free_req; sb->s_root = root_dentry; + fc->mounted = 1; fc->connected = 1; kobject_get(&fc->kobj); file->private_data = fc; -- cgit v1.2.3