From 0cd1eb9a4160a96e0ec9b93b2e7b489f449bf22d Mon Sep 17 00:00:00 2001 From: Vivek Goyal Date: Wed, 6 Mar 2019 16:51:40 -0500 Subject: fuse: separate fuse device allocation and installation in fuse_conn As of now fuse_dev_alloc() both allocates a fuse device and installs it in fuse_conn list. fuse_dev_alloc() can fail if fuse_device allocation fails. virtio-fs needs to initialize multiple fuse devices (one per virtio queue). It initializes one fuse device as part of call to fuse_fill_super_common() and rest of the devices are allocated and installed after that. But, we can't afford to fail after calling fuse_fill_super_common() as we don't have a way to undo all the actions done by fuse_fill_super_common(). So to avoid failures after the call to fuse_fill_super_common(), pre-allocate all fuse devices early and install them into fuse connection later. This patch provides two separate helpers for fuse device allocation and fuse device installation in fuse_conn. Signed-off-by: Vivek Goyal Signed-off-by: Miklos Szeredi --- fs/fuse/inode.c | 25 +++++++++++++++++++++---- 1 file changed, 21 insertions(+), 4 deletions(-) (limited to 'fs/fuse/inode.c') diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c index 734fdd597c3e..6a0f31faaeaa 100644 --- a/fs/fuse/inode.c +++ b/fs/fuse/inode.c @@ -1045,7 +1045,7 @@ static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb) return 0; } -struct fuse_dev *fuse_dev_alloc(struct fuse_conn *fc) +struct fuse_dev *fuse_dev_alloc(void) { struct fuse_dev *fud; struct list_head *pq; @@ -1061,16 +1061,33 @@ struct fuse_dev *fuse_dev_alloc(struct fuse_conn *fc) } fud->pq.processing = pq; - fud->fc = fuse_conn_get(fc); fuse_pqueue_init(&fud->pq); + return fud; +} +EXPORT_SYMBOL_GPL(fuse_dev_alloc); + +void fuse_dev_install(struct fuse_dev *fud, struct fuse_conn *fc) +{ + fud->fc = fuse_conn_get(fc); spin_lock(&fc->lock); list_add_tail(&fud->entry, &fc->devices); spin_unlock(&fc->lock); +} +EXPORT_SYMBOL_GPL(fuse_dev_install); +struct fuse_dev *fuse_dev_alloc_install(struct fuse_conn *fc) +{ + struct fuse_dev *fud; + + fud = fuse_dev_alloc(); + if (!fud) + return NULL; + + fuse_dev_install(fud, fc); return fud; } -EXPORT_SYMBOL_GPL(fuse_dev_alloc); +EXPORT_SYMBOL_GPL(fuse_dev_alloc_install); void fuse_dev_free(struct fuse_dev *fud) { @@ -1132,7 +1149,7 @@ int fuse_fill_super_common(struct super_block *sb, struct fuse_fs_context *ctx) if (sb->s_user_ns != &init_user_ns) sb->s_xattr = fuse_no_acl_xattr_handlers; - fud = fuse_dev_alloc(fc); + fud = fuse_dev_alloc_install(fc); if (!fud) goto err; -- cgit v1.2.3