From: Jan Kara Subject: [PATCH 1/3] fs: Create __block_page_mkwrite() helper passing error values back Date: Wed, 18 May 2011 17:18:00 +0200 Message-ID: <1305731882-8334-2-git-send-email-jack@suse.cz> References: <1305731882-8334-1-git-send-email-jack@suse.cz> Cc: linux-ext4@vger.kernel.org, Al Viro , tytso@mit.edu, Christoph Hellwig , Jan Kara To: linux-fsdevel@vger.kernel.org Return-path: In-Reply-To: <1305731882-8334-1-git-send-email-jack@suse.cz> Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org Create __block_page_mkwrite() helper which does all what block_page_mkwrite() does except that it passes back errors from __block_write_begin / block_commit_write calls. Signed-off-by: Jan Kara --- fs/buffer.c | 28 +++++++++++++++------------- include/linux/buffer_head.h | 14 ++++++++++++++ 2 files changed, 29 insertions(+), 13 deletions(-) diff --git a/fs/buffer.c b/fs/buffer.c index a08bb8e..9c5dd88 100644 --- a/fs/buffer.c +++ b/fs/buffer.c @@ -2332,21 +2332,21 @@ EXPORT_SYMBOL(block_commit_write); * beyond EOF, then the page is guaranteed safe against truncation until we * unlock the page. */ -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) { struct page *page = vmf->page; struct inode *inode = vma->vm_file->f_path.dentry->d_inode; unsigned long end; loff_t size; - int ret = VM_FAULT_NOPAGE; /* make the VM retry the fault */ + int ret = 0; lock_page(page); size = i_size_read(inode); if ((page->mapping != inode->i_mapping) || (page_offset(page) > size)) { - /* page got truncated out from underneath us */ + /* We overload EFAULT to mean page got truncated */ + ret = -EFAULT; unlock_page(page); goto out; } @@ -2361,18 +2361,20 @@ block_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf, if (!ret) ret = block_commit_write(page, 0, end); - if (unlikely(ret)) { + if (unlikely(ret < 0)) unlock_page(page); - if (ret == -ENOMEM) - ret = VM_FAULT_OOM; - else /* -ENOSPC, -EIO, etc */ - ret = VM_FAULT_SIGBUS; - } else - ret = VM_FAULT_LOCKED; - out: 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 = __block_page_mkwrite(vma, vmf, get_block); + + return block_page_mkwrite_return(ret); +} EXPORT_SYMBOL(block_page_mkwrite); /* diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h index f5df235..2bf6a91 100644 --- a/include/linux/buffer_head.h +++ b/include/linux/buffer_head.h @@ -217,8 +217,22 @@ 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 */ +static inline int block_page_mkwrite_return(int err) +{ + if (err == 0) + return VM_FAULT_LOCKED; + if (err == -EFAULT) + return VM_FAULT_NOPAGE; + if (err == -ENOMEM) + return VM_FAULT_OOM; + /* -ENOSPC, -EDQUOT, -EIO ... */ + return VM_FAULT_SIGBUS; +} sector_t generic_block_bmap(struct address_space *, sector_t, get_block_t *); int block_truncate_page(struct address_space *, loff_t, get_block_t *); int nobh_write_begin(struct address_space *, loff_t, unsigned, unsigned, -- 1.7.1