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

14 files changed, 86 insertions, 102 deletions

diff --git a/fs/9p/cache.h b/fs/9p/cache.h
index 2f9675491095..247e47e54bcc 100644
--- a/fs/9p/cache.h
+++ b/fs/9p/cache.h
@@ -21,6 +21,7 @@
  */
 
 #ifndef _9P_CACHE_H
+#define _9P_CACHE_H
 #ifdef CONFIG_9P_FSCACHE
 #include <linux/fscache.h>
 #include <linux/spinlock.h>
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index 5f399ea1d20a..3a93755e880f 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -488,7 +488,7 @@ static inline int arch_elf_pt_proc(struct elfhdr *ehdr,
 }
 
 /**
- * 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
@@ -760,16 +760,16 @@ static int load_elf_binary(struct linux_binprm *bprm)
                          */
                         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++;
diff --git a/fs/buffer.c b/fs/buffer.c
index 51aff0296ce2..4f4cd959da7c 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -2420,9 +2420,9 @@ EXPORT_SYMBOL(block_commit_write);
  * 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;
@@ -2459,26 +2459,6 @@ 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);
 
 /*
diff --git a/fs/cachefiles/namei.c b/fs/cachefiles/namei.c
index fc1056f5c96a..c4b893453e0e 100644
--- a/fs/cachefiles/namei.c
+++ b/fs/cachefiles/namei.c
@@ -655,6 +655,8 @@ lookup_again:
                         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 {
diff --git a/fs/cachefiles/rdwr.c b/fs/cachefiles/rdwr.c
index 3cbb0e834694..7a6b02f72787 100644
--- a/fs/cachefiles/rdwr.c
+++ b/fs/cachefiles/rdwr.c
@@ -414,9 +414,6 @@ int cachefiles_read_or_alloc_page(struct fscache_retrieval *op,
         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;
@@ -711,9 +708,6 @@ int cachefiles_read_or_alloc_pages(struct fscache_retrieval *op,
         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);
@@ -905,6 +899,15 @@ int cachefiles_write_page(struct fscache_storage *op, struct page *page)
         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;
@@ -912,40 +915,38 @@ int cachefiles_write_page(struct fscache_storage *op, struct page *page)
         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;
-
-                /* 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);
-                        }
-                }
-
-                data = kmap(page);
-                ret = __kernel_write(file, data, len, &pos);
-                kunmap(page);
-                if (ret != len)
-                        ret = -EIO;
-                fput(file);
+                goto error_2;
         }
 
-        if (ret < 0) {
-                if (ret == -EIO)
-                        cachefiles_io_error_obj(
-                                object, "Write page to backing file failed");
-                ret = -ENOBUFS;
+        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);
+                }
         }
 
-        _leave(" = %d", ret);
-        return ret;
+        data = kmap(page);
+        ret = __kernel_write(file, data, len, &pos);
+        kunmap(page);
+        fput(file);
+        if (ret != len)
+                goto error_eio;
+
+        _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;
 }
 
 /*
diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c
index 5d8f35f1382a..b7fcc0de0b2f 100644
--- a/fs/debugfs/inode.c
+++ b/fs/debugfs/inode.c
@@ -271,8 +271,12 @@ static struct dentry *start_creating(const char *name, struct dentry *parent)
                 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;
 }
 
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 7d1aad1d9313..ea433a7f4bca 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -5283,7 +5283,7 @@ int ext4_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
             !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));
@@ -5330,7 +5330,7 @@ retry_alloc:
                 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)) {
diff --git a/fs/fscache/netfs.c b/fs/fscache/netfs.c
index 6d941f56faf4..9b28649df3a1 100644
--- a/fs/fscache/netfs.c
+++ b/fs/fscache/netfs.c
@@ -22,6 +22,7 @@ static LIST_HEAD(fscache_netfs_list);
 int __fscache_register_netfs(struct fscache_netfs *netfs)
 {
         struct fscache_netfs *ptr;
+        struct fscache_cookie *cookie;
         int ret;
 
         _enter("{%s}", netfs->name);
@@ -29,29 +30,25 @@ int __fscache_register_netfs(struct fscache_netfs *netfs)
         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);
@@ -62,6 +59,10 @@ int __fscache_register_netfs(struct fscache_netfs *netfs)
                         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;
 
@@ -70,11 +71,8 @@ int __fscache_register_netfs(struct fscache_netfs *netfs)
 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;
diff --git a/fs/fscache/page.c b/fs/fscache/page.c
index 79483b3d8c6f..6b35fc4860a0 100644
--- a/fs/fscache/page.c
+++ b/fs/fscache/page.c
@@ -816,7 +816,7 @@ static void fscache_write_op(struct fscache_operation *_op)
                 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;
         }
diff --git a/fs/nilfs2/file.c b/fs/nilfs2/file.c
index 54575e3cc1a2..088ba001c6ef 100644
--- a/fs/nilfs2/file.c
+++ b/fs/nilfs2/file.c
@@ -109,7 +109,7 @@ static int nilfs_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
                 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;
diff --git a/fs/pipe.c b/fs/pipe.c
index 8865f7963700..42cf8ddf0e55 100644
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -366,18 +366,17 @@ pipe_write(struct kiocb *iocb, struct iov_iter *from)
                 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;
                 }
@@ -693,17 +692,20 @@ int create_pipe_files(struct file **res, int flags)
 
         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;
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index e78feb400e22..f80e90f95ad8 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -1506,7 +1506,7 @@ xfs_filemap_page_mkwrite(
                 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);
         }
 
diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h
index e6797ded700e..89d9aa9e79bf 100644
--- a/include/linux/buffer_head.h
+++ b/include/linux/buffer_head.h
@@ -227,8 +227,6 @@ int cont_write_begin(struct file *, struct address_space *, loff_t,
                         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 */
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 6230eb2a9cca..3aa514254161 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1665,8 +1665,6 @@ struct inode_operations {
                            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,