Merge branch 'for-linus-2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull vfs update from Al Viro:

- misc stable fixes

- trivial kernel-doc and comment fixups

- remove never-used block_page_mkwrite() wrapper function, and rename
the function that is _actually_ used to not have double underscores.

* 'for-linus-2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
fs: 9p: cache.h: Add #define of include guard
vfs: remove stale comment in inode_operations
vfs: remove unused wrapper block_page_mkwrite()
binfmt_elf: Correct `arch_check_elf's description
fs: fix writeback.c kernel-doc warnings
fs: fix inode.c kernel-doc warning
fs/pipe.c: return error code rather than 0 in pipe_write()
fs/pipe.c: preserve alloc_file() error code
binfmt_elf: Don't clobber passed executable's file header
FS-Cache: Handle a write to the page immediately beyond the EOF marker
cachefiles: perform test on s_blocksize when opening cache file.
FS-Cache: Don't override netfs's primary_index if registering failed
FS-Cache: Increase reference of parent after registering, netfs success
debugfs: fix refcount imbalance in start_creating

fs/9p/cache.h

···
  */
 
 #ifndef _9P_CACHE_H
+#define _9P_CACHE_H
 #ifdef CONFIG_9P_FSCACHE
 #include <linux/fscache.h>
 #include <linux/spinlock.h>

fs/binfmt_elf.c

···
 }
 
 /**
- * arch_check_elf() - check a PT_LOPROC..PT_HIPROC ELF program header
+ * arch_check_elf() - check an ELF executable
  * @ehdr:	The main ELF header
  * @has_interp:	True if the ELF has an interpreter, else false.
  * @state:	Architecture-specific state preserved throughout the process
···
 			 */
 			would_dump(bprm, interpreter);
 
-			retval = kernel_read(interpreter, 0, bprm->buf,
-					     BINPRM_BUF_SIZE);
-			if (retval != BINPRM_BUF_SIZE) {
+			/* Get the exec headers */
+			retval = kernel_read(interpreter, 0,
+					     (void *)&loc->interp_elf_ex,
+					     sizeof(loc->interp_elf_ex));
+			if (retval != sizeof(loc->interp_elf_ex)) {
 				if (retval >= 0)
 					retval = -EIO;
 				goto out_free_dentry;
 			}
 
-			/* Get the exec headers */
-			loc->interp_elf_ex = *((struct elfhdr *)bprm->buf);
 			break;
 		}
 		elf_ppnt++;

fs/buffer.c

···
  * unlock the page.
  *
  * Direct callers of this function should protect against filesystem freezing
- * using sb_start_write() - sb_end_write() functions.
+ * using sb_start_pagefault() - sb_end_pagefault() functions.
  */
-int __block_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf,
+int block_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf,
 			 get_block_t get_block)
 {
 	struct page *page = vmf->page;
···
 out_unlock:
 	unlock_page(page);
 	return ret;
-}
-EXPORT_SYMBOL(__block_page_mkwrite);
-
-int block_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf,
-		   get_block_t get_block)
-{
-	int ret;
-	struct super_block *sb = file_inode(vma->vm_file)->i_sb;
-
-	sb_start_pagefault(sb);
-
-	/*
-	 * Update file times before taking page lock. We may end up failing the
-	 * fault so this update may be superfluous but who really cares...
-	 */
-	file_update_time(vma->vm_file);
-
-	ret = __block_page_mkwrite(vma, vmf, get_block);
-	sb_end_pagefault(sb);
-	return block_page_mkwrite_return(ret);
 }
 EXPORT_SYMBOL(block_page_mkwrite);
 

fs/cachefiles/namei.c

···
 			aops = d_backing_inode(object->dentry)->i_mapping->a_ops;
 			if (!aops->bmap)
 				goto check_error;
+			if (object->dentry->d_sb->s_blocksize > PAGE_SIZE)
+				goto check_error;
 
 			object->backer = object->dentry;
 		} else {

fs/cachefiles/rdwr.c

···
 	ASSERT(inode->i_mapping->a_ops->readpages);
 
 	/* calculate the shift required to use bmap */
-	if (inode->i_sb->s_blocksize > PAGE_SIZE)
-		goto enobufs;
-
 	shift = PAGE_SHIFT - inode->i_sb->s_blocksize_bits;
 
 	op->op.flags &= FSCACHE_OP_KEEP_FLAGS;
···
 	ASSERT(inode->i_mapping->a_ops->readpages);
 
 	/* calculate the shift required to use bmap */
-	if (inode->i_sb->s_blocksize > PAGE_SIZE)
-		goto all_enobufs;
-
 	shift = PAGE_SHIFT - inode->i_sb->s_blocksize_bits;
 
 	pagevec_init(&pagevec, 0);
···
 	cache = container_of(object->fscache.cache,
 			     struct cachefiles_cache, cache);
 
+	pos = (loff_t)page->index << PAGE_SHIFT;
+
+	/* We mustn't write more data than we have, so we have to beware of a
+	 * partial page at EOF.
+	 */
+	eof = object->fscache.store_limit_l;
+	if (pos >= eof)
+		goto error;
+
 	/* write the page to the backing filesystem and let it store it in its
 	 * own time */
 	path.mnt = cache->mnt;
···
 	file = dentry_open(&path, O_RDWR | O_LARGEFILE, cache->cache_cred);
 	if (IS_ERR(file)) {
 		ret = PTR_ERR(file);
-	} else {
-		pos = (loff_t) page->index << PAGE_SHIFT;
+		goto error_2;
+	}
 
-		/* we mustn't write more data than we have, so we have
-		 * to beware of a partial page at EOF */
-		eof = object->fscache.store_limit_l;
-		len = PAGE_SIZE;
-		if (eof & ~PAGE_MASK) {
-			ASSERTCMP(pos, <, eof);
-			if (eof - pos < PAGE_SIZE) {
-				_debug("cut short %llx to %llx",
-				       pos, eof);
-				len = eof - pos;
-				ASSERTCMP(pos + len, ==, eof);
-			}
+	len = PAGE_SIZE;
+	if (eof & ~PAGE_MASK) {
+		if (eof - pos < PAGE_SIZE) {
+			_debug("cut short %llx to %llx",
+			       pos, eof);
+			len = eof - pos;
+			ASSERTCMP(pos + len, ==, eof);
 		}
-
-		data = kmap(page);
-		ret = __kernel_write(file, data, len, &pos);
-		kunmap(page);
-		if (ret != len)
-			ret = -EIO;
-		fput(file);
 	}
 
-	if (ret < 0) {
-		if (ret == -EIO)
-			cachefiles_io_error_obj(
-				object, "Write page to backing file failed");
-		ret = -ENOBUFS;
-	}
+	data = kmap(page);
+	ret = __kernel_write(file, data, len, &pos);
+	kunmap(page);
+	fput(file);
+	if (ret != len)
+		goto error_eio;
 
-	_leave(" = %d", ret);
-	return ret;
+	_leave(" = 0");
+	return 0;
+
+error_eio:
+	ret = -EIO;
+error_2:
+	if (ret == -EIO)
+		cachefiles_io_error_obj(object,
+					"Write page to backing file failed");
+error:
+	_leave(" = -ENOBUFS [%d]", ret);
+	return -ENOBUFS;
 }
 
 /*

fs/debugfs/inode.c

···
 		dput(dentry);
 		dentry = ERR_PTR(-EEXIST);
 	}
-	if (IS_ERR(dentry))
+
+	if (IS_ERR(dentry)) {
 		mutex_unlock(&d_inode(parent)->i_mutex);
+		simple_release_fs(&debugfs_mount, &debugfs_mount_count);
+	}
+
 	return dentry;
 }
 

fs/ext4/inode.c

···
 	    !ext4_should_journal_data(inode) &&
 	    !ext4_nonda_switch(inode->i_sb)) {
 		do {
-			ret = __block_page_mkwrite(vma, vmf,
+			ret = block_page_mkwrite(vma, vmf,
 						   ext4_da_get_block_prep);
 		} while (ret == -ENOSPC &&
 		       ext4_should_retry_alloc(inode->i_sb, &retries));
···
 		ret = VM_FAULT_SIGBUS;
 		goto out;
 	}
-	ret = __block_page_mkwrite(vma, vmf, get_block);
+	ret = block_page_mkwrite(vma, vmf, get_block);
 	if (!ret && ext4_should_journal_data(inode)) {
 		if (ext4_walk_page_buffers(handle, page_buffers(page), 0,
 			  PAGE_CACHE_SIZE, NULL, do_journal_get_write_access)) {

fs/fscache/netfs.c

···
 int __fscache_register_netfs(struct fscache_netfs *netfs)
 {
 	struct fscache_netfs *ptr;
+	struct fscache_cookie *cookie;
 	int ret;
 
 	_enter("{%s}", netfs->name);
···
 	INIT_LIST_HEAD(&netfs->link);
 
 	/* allocate a cookie for the primary index */
-	netfs->primary_index =
-		kmem_cache_zalloc(fscache_cookie_jar, GFP_KERNEL);
+	cookie = kmem_cache_zalloc(fscache_cookie_jar, GFP_KERNEL);
 
-	if (!netfs->primary_index) {
+	if (!cookie) {
 		_leave(" = -ENOMEM");
 		return -ENOMEM;
 	}
 
 	/* initialise the primary index cookie */
-	atomic_set(&netfs->primary_index->usage, 1);
-	atomic_set(&netfs->primary_index->n_children, 0);
-	atomic_set(&netfs->primary_index->n_active, 1);
+	atomic_set(&cookie->usage, 1);
+	atomic_set(&cookie->n_children, 0);
+	atomic_set(&cookie->n_active, 1);
 
-	netfs->primary_index->def		= &fscache_fsdef_netfs_def;
-	netfs->primary_index->parent		= &fscache_fsdef_index;
-	netfs->primary_index->netfs_data	= netfs;
-	netfs->primary_index->flags		= 1 << FSCACHE_COOKIE_ENABLED;
+	cookie->def		= &fscache_fsdef_netfs_def;
+	cookie->parent		= &fscache_fsdef_index;
+	cookie->netfs_data	= netfs;
+	cookie->flags		= 1 << FSCACHE_COOKIE_ENABLED;
 
-	atomic_inc(&netfs->primary_index->parent->usage);
-	atomic_inc(&netfs->primary_index->parent->n_children);
-
-	spin_lock_init(&netfs->primary_index->lock);
-	INIT_HLIST_HEAD(&netfs->primary_index->backing_objects);
+	spin_lock_init(&cookie->lock);
+	INIT_HLIST_HEAD(&cookie->backing_objects);
 
 	/* check the netfs type is not already present */
 	down_write(&fscache_addremove_sem);
···
 			goto already_registered;
 	}
 
+	atomic_inc(&cookie->parent->usage);
+	atomic_inc(&cookie->parent->n_children);
+
+	netfs->primary_index = cookie;
 	list_add(&netfs->link, &fscache_netfs_list);
 	ret = 0;
 
···
 already_registered:
 	up_write(&fscache_addremove_sem);
 
-	if (ret < 0) {
-		netfs->primary_index->parent = NULL;
-		__fscache_cookie_put(netfs->primary_index);
-		netfs->primary_index = NULL;
-	}
+	if (ret < 0)
+		kmem_cache_free(fscache_cookie_jar, cookie);
 
 	_leave(" = %d", ret);
 	return ret;

fs/fscache/page.c

···
 		goto superseded;
 	page = results[0];
 	_debug("gang %d [%lx]", n, page->index);
-	if (page->index > op->store_limit) {
+	if (page->index >= op->store_limit) {
 		fscache_stat(&fscache_n_store_pages_over_limit);
 		goto superseded;
 	}

fs/nilfs2/file.c

···
 		goto out;
 
 	file_update_time(vma->vm_file);
-	ret = __block_page_mkwrite(vma, vmf, nilfs_get_block);
+	ret = block_page_mkwrite(vma, vmf, nilfs_get_block);
 	if (ret) {
 		nilfs_transaction_abort(inode->i_sb);
 		goto out;

fs/pipe.c

···
 		int offset = buf->offset + buf->len;
 
 		if (ops->can_merge && offset + chars <= PAGE_SIZE) {
-			int error = ops->confirm(pipe, buf);
-			if (error)
+			ret = ops->confirm(pipe, buf);
+			if (ret)
 				goto out;
 
 			ret = copy_page_from_iter(buf->page, offset, chars, from);
 			if (unlikely(ret < chars)) {
-				error = -EFAULT;
+				ret = -EFAULT;
 				goto out;
 			}
 			do_wakeup = 1;
-			buf->len += chars;
-			ret = chars;
+			buf->len += ret;
 			if (!iov_iter_count(from))
 				goto out;
 		}
···
 
 	d_instantiate(path.dentry, inode);
 
-	err = -ENFILE;
 	f = alloc_file(&path, FMODE_WRITE, &pipefifo_fops);
-	if (IS_ERR(f))
+	if (IS_ERR(f)) {
+		err = PTR_ERR(f);
 		goto err_dentry;
+	}
 
 	f->f_flags = O_WRONLY | (flags & (O_NONBLOCK | O_DIRECT));
 	f->private_data = inode->i_pipe;
 
 	res[0] = alloc_file(&path, FMODE_READ, &pipefifo_fops);
-	if (IS_ERR(res[0]))
+	if (IS_ERR(res[0])) {
+		err = PTR_ERR(res[0]);
 		goto err_file;
+	}
 
 	path_get(&path);
 	res[0]->private_data = inode->i_pipe;

fs/xfs/xfs_file.c

···
 		ret = __dax_mkwrite(vma, vmf, xfs_get_blocks_direct,
 				    xfs_end_io_dax_write);
 	} else {
-		ret = __block_page_mkwrite(vma, vmf, xfs_get_blocks);
+		ret = block_page_mkwrite(vma, vmf, xfs_get_blocks);
 		ret = block_page_mkwrite_return(ret);
 	}
 

include/linux/buffer_head.h

···
 			get_block_t *, loff_t *);
 int generic_cont_expand_simple(struct inode *inode, loff_t size);
 int block_commit_write(struct page *page, unsigned from, unsigned to);
-int __block_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf,
-				get_block_t get_block);
 int block_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf,
 				get_block_t get_block);
 /* Convert errno to return value from ->page_mkwrite() call */

include/linux/fs.h

···
 			   umode_t create_mode, int *opened);
 	int (*tmpfile) (struct inode *, struct dentry *, umode_t);
 	int (*set_acl)(struct inode *, struct posix_acl *, int);
-
-	/* WARNING: probably going away soon, do not use! */
 } ____cacheline_aligned;
 
 ssize_t rw_copy_check_uvector(int type, const struct iovec __user * uvector,