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https://github.com/joel16/android_kernel_sony_msm8994.git
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Revert "[fuse] fix deadlock between fuse_put_super() and request_end()"
This reverts 73ce8355c2
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 <miklos@szeredi.hu>
This commit is contained in:
parent
4d5c34ec7b
commit
5a5fb1ea74
@ -128,14 +128,20 @@ void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req)
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}
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}
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void fuse_remove_background(struct fuse_conn *fc, struct fuse_req *req)
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void fuse_release_background(struct fuse_conn *fc, struct fuse_req *req)
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{
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list_del_init(&req->bg_entry);
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iput(req->inode);
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iput(req->inode2);
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if (req->file)
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fput(req->file);
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spin_lock(&fc->lock);
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list_del(&req->bg_entry);
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if (fc->num_background == FUSE_MAX_BACKGROUND) {
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fc->blocked = 0;
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wake_up_all(&fc->blocked_waitq);
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}
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fc->num_background--;
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spin_unlock(&fc->lock);
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}
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/*
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@ -165,27 +171,17 @@ static void request_end(struct fuse_conn *fc, struct fuse_req *req)
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wake_up(&req->waitq);
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fuse_put_request(fc, req);
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} else {
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struct inode *inode = req->inode;
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struct inode *inode2 = req->inode2;
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struct file *file = req->file;
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void (*end) (struct fuse_conn *, struct fuse_req *) = req->end;
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req->end = NULL;
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req->inode = NULL;
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req->inode2 = NULL;
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req->file = NULL;
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if (!list_empty(&req->bg_entry))
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fuse_remove_background(fc, req);
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spin_unlock(&fc->lock);
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down_read(&fc->sbput_sem);
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if (fc->mounted)
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fuse_release_background(fc, req);
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up_read(&fc->sbput_sem);
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if (end)
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end(fc, req);
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else
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fuse_put_request(fc, req);
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if (file)
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fput(file);
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iput(inode);
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iput(inode2);
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}
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}
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@ -258,9 +258,15 @@ struct fuse_conn {
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/** waitq for blocked connection */
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wait_queue_head_t blocked_waitq;
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/** RW semaphore for exclusion with fuse_put_super() */
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struct rw_semaphore sbput_sem;
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/** The next unique request id */
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u64 reqctr;
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/** Mount is active */
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unsigned mounted;
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/** Connection established, cleared on umount, connection
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abort and device release */
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unsigned connected;
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@ -471,11 +477,11 @@ void request_send_noreply(struct fuse_conn *fc, struct fuse_req *req);
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void request_send_background(struct fuse_conn *fc, struct fuse_req *req);
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/**
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* Remove request from the the background list
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* Release inodes and file associated with background request
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*/
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void fuse_remove_background(struct fuse_conn *fc, struct fuse_req *req);
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void fuse_release_background(struct fuse_conn *fc, struct fuse_req *req);
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/** Abort all requests */
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/* Abort all requests */
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void fuse_abort_conn(struct fuse_conn *fc);
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/**
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@ -204,26 +204,17 @@ static void fuse_put_super(struct super_block *sb)
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{
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struct fuse_conn *fc = get_fuse_conn_super(sb);
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down_write(&fc->sbput_sem);
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while (!list_empty(&fc->background))
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fuse_release_background(fc,
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list_entry(fc->background.next,
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struct fuse_req, bg_entry));
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spin_lock(&fc->lock);
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fc->mounted = 0;
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fc->connected = 0;
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while (!list_empty(&fc->background)) {
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struct fuse_req *req = list_entry(fc->background.next,
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struct fuse_req, bg_entry);
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struct inode *inode = req->inode;
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struct inode *inode2 = req->inode2;
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/* File would hold a reference to vfsmount */
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BUG_ON(req->file);
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req->inode = NULL;
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req->inode2 = NULL;
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fuse_remove_background(fc, req);
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spin_unlock(&fc->lock);
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iput(inode);
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iput(inode2);
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spin_lock(&fc->lock);
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}
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spin_unlock(&fc->lock);
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up_write(&fc->sbput_sem);
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/* Flush all readers on this fs */
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kill_fasync(&fc->fasync, SIGIO, POLL_IN);
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wake_up_all(&fc->waitq);
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@ -395,6 +386,7 @@ static struct fuse_conn *new_conn(void)
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INIT_LIST_HEAD(&fc->processing);
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INIT_LIST_HEAD(&fc->io);
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INIT_LIST_HEAD(&fc->background);
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init_rwsem(&fc->sbput_sem);
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kobj_set_kset_s(fc, connections_subsys);
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kobject_init(&fc->kobj);
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atomic_set(&fc->num_waiting, 0);
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@ -549,6 +541,7 @@ static int fuse_fill_super(struct super_block *sb, void *data, int silent)
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goto err_free_req;
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sb->s_root = root_dentry;
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fc->mounted = 1;
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fc->connected = 1;
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kobject_get(&fc->kobj);
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file->private_data = fc;
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