From 5c672ab3f0ee0f78f7acad183f34db0f8781a200 Mon Sep 17 00:00:00 2001 From: Miklos Szeredi Date: Thu, 30 Jun 2016 13:10:49 +0200 Subject: fuse: serialize dirops by default Negotiate with userspace filesystems whether they support parallel readdir and lookup. Disable parallelism by default for fear of breaking fuse filesystems. Signed-off-by: Miklos Szeredi Fixes: 9902af79c01a ("parallel lookups: actual switch to rwsem") Fixes: d9b3dbdcfd62 ("fuse: switch to ->iterate_shared()") diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c index ccd4971..264f07c 100644 --- a/fs/fuse/dir.c +++ b/fs/fuse/dir.c @@ -341,8 +341,10 @@ static struct dentry *fuse_lookup(struct inode *dir, struct dentry *entry, struct dentry *newent; bool outarg_valid = true; + fuse_lock_inode(dir); err = fuse_lookup_name(dir->i_sb, get_node_id(dir), &entry->d_name, &outarg, &inode); + fuse_unlock_inode(dir); if (err == -ENOENT) { outarg_valid = false; err = 0; @@ -1341,7 +1343,9 @@ static int fuse_readdir(struct file *file, struct dir_context *ctx) fuse_read_fill(req, file, ctx->pos, PAGE_SIZE, FUSE_READDIR); } + fuse_lock_inode(inode); fuse_request_send(fc, req); + fuse_unlock_inode(inode); nbytes = req->out.args[0].size; err = req->out.h.error; fuse_put_request(fc, req); diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h index eddbe02..929c383 100644 --- a/fs/fuse/fuse_i.h +++ b/fs/fuse/fuse_i.h @@ -110,6 +110,9 @@ struct fuse_inode { /** Miscellaneous bits describing inode state */ unsigned long state; + + /** Lock for serializing lookup and readdir for back compatibility*/ + struct mutex mutex; }; /** FUSE inode state bits */ @@ -540,6 +543,9 @@ struct fuse_conn { /** write-back cache policy (default is write-through) */ unsigned writeback_cache:1; + /** allow parallel lookups and readdir (default is serialized) */ + unsigned parallel_dirops:1; + /* * The following bitfields are only for optimization purposes * and hence races in setting them will not cause malfunction @@ -956,4 +962,7 @@ int fuse_do_setattr(struct inode *inode, struct iattr *attr, void fuse_set_initialized(struct fuse_conn *fc); +void fuse_unlock_inode(struct inode *inode); +void fuse_lock_inode(struct inode *inode); + #endif /* _FS_FUSE_I_H */ diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c index 1ce6766..9961d843 100644 --- a/fs/fuse/inode.c +++ b/fs/fuse/inode.c @@ -97,6 +97,7 @@ static struct inode *fuse_alloc_inode(struct super_block *sb) INIT_LIST_HEAD(&fi->queued_writes); INIT_LIST_HEAD(&fi->writepages); init_waitqueue_head(&fi->page_waitq); + mutex_init(&fi->mutex); fi->forget = fuse_alloc_forget(); if (!fi->forget) { kmem_cache_free(fuse_inode_cachep, inode); @@ -117,6 +118,7 @@ static void fuse_destroy_inode(struct inode *inode) struct fuse_inode *fi = get_fuse_inode(inode); BUG_ON(!list_empty(&fi->write_files)); BUG_ON(!list_empty(&fi->queued_writes)); + mutex_destroy(&fi->mutex); kfree(fi->forget); call_rcu(&inode->i_rcu, fuse_i_callback); } @@ -351,6 +353,18 @@ int fuse_reverse_inval_inode(struct super_block *sb, u64 nodeid, return 0; } +void fuse_lock_inode(struct inode *inode) +{ + if (!get_fuse_conn(inode)->parallel_dirops) + mutex_lock(&get_fuse_inode(inode)->mutex); +} + +void fuse_unlock_inode(struct inode *inode) +{ + if (!get_fuse_conn(inode)->parallel_dirops) + mutex_unlock(&get_fuse_inode(inode)->mutex); +} + static void fuse_umount_begin(struct super_block *sb) { fuse_abort_conn(get_fuse_conn_super(sb)); @@ -898,6 +912,8 @@ static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req) fc->async_dio = 1; if (arg->flags & FUSE_WRITEBACK_CACHE) fc->writeback_cache = 1; + if (arg->flags & FUSE_PARALLEL_DIROPS) + fc->parallel_dirops = 1; if (arg->time_gran && arg->time_gran <= 1000000000) fc->sb->s_time_gran = arg->time_gran; } else { @@ -928,7 +944,8 @@ static void fuse_send_init(struct fuse_conn *fc, struct fuse_req *req) FUSE_SPLICE_WRITE | FUSE_SPLICE_MOVE | FUSE_SPLICE_READ | FUSE_FLOCK_LOCKS | FUSE_IOCTL_DIR | FUSE_AUTO_INVAL_DATA | FUSE_DO_READDIRPLUS | FUSE_READDIRPLUS_AUTO | FUSE_ASYNC_DIO | - FUSE_WRITEBACK_CACHE | FUSE_NO_OPEN_SUPPORT; + FUSE_WRITEBACK_CACHE | FUSE_NO_OPEN_SUPPORT | + FUSE_PARALLEL_DIROPS; req->in.h.opcode = FUSE_INIT; req->in.numargs = 1; req->in.args[0].size = sizeof(*arg); diff --git a/include/uapi/linux/fuse.h b/include/uapi/linux/fuse.h index 5974fae..27e1736 100644 --- a/include/uapi/linux/fuse.h +++ b/include/uapi/linux/fuse.h @@ -105,6 +105,9 @@ * * 7.24 * - add FUSE_LSEEK for SEEK_HOLE and SEEK_DATA support + * + * 7.25 + * - add FUSE_PARALLEL_DIROPS */ #ifndef _LINUX_FUSE_H @@ -140,7 +143,7 @@ #define FUSE_KERNEL_VERSION 7 /** Minor version number of this interface */ -#define FUSE_KERNEL_MINOR_VERSION 24 +#define FUSE_KERNEL_MINOR_VERSION 25 /** The node ID of the root inode */ #define FUSE_ROOT_ID 1 @@ -234,6 +237,7 @@ struct fuse_file_lock { * FUSE_ASYNC_DIO: asynchronous direct I/O submission * FUSE_WRITEBACK_CACHE: use writeback cache for buffered writes * FUSE_NO_OPEN_SUPPORT: kernel supports zero-message opens + * FUSE_PARALLEL_DIROPS: allow parallel lookups and readdir */ #define FUSE_ASYNC_READ (1 << 0) #define FUSE_POSIX_LOCKS (1 << 1) @@ -253,6 +257,7 @@ struct fuse_file_lock { #define FUSE_ASYNC_DIO (1 << 15) #define FUSE_WRITEBACK_CACHE (1 << 16) #define FUSE_NO_OPEN_SUPPORT (1 << 17) +#define FUSE_PARALLEL_DIROPS (1 << 18) /** * CUSE INIT request/reply flags -- cgit v0.10.2