Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964971AbVKHUkp (ORCPT ); Tue, 8 Nov 2005 15:40:45 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S965094AbVKHUkp (ORCPT ); Tue, 8 Nov 2005 15:40:45 -0500 Received: from mail.parknet.co.jp ([210.171.160.6]:64527 "EHLO mail.parknet.co.jp") by vger.kernel.org with ESMTP id S964971AbVKHUko (ORCPT ); Tue, 8 Nov 2005 15:40:44 -0500 To: Andrew Morton Cc: linux-kernel@vger.kernel.org Subject: Re: [PATCH 7/6] fat: Support a truncate() for expanding size References: <87hdaotlci.fsf@devron.myhome.or.jp> <87d5lctl5y.fsf@devron.myhome.or.jp> <878xw0tl3r.fsf_-_@devron.myhome.or.jp> <874q6otl0q.fsf_-_@devron.myhome.or.jp> <87zmogs6cs.fsf_-_@devron.myhome.or.jp> <87vez4s6b7.fsf_-_@devron.myhome.or.jp> <87r79ss658.fsf_-_@devron.myhome.or.jp> <20051107170626.4d08e8d6.akpm@osdl.org> <87ek5rx1ur.fsf@devron.myhome.or.jp> <20051107201934.4c01a472.akpm@osdl.org> <874q6nww63.fsf@devron.myhome.or.jp> From: OGAWA Hirofumi Date: Wed, 09 Nov 2005 05:40:32 +0900 In-Reply-To: <874q6nww63.fsf@devron.myhome.or.jp> (OGAWA Hirofumi's message of "Tue, 08 Nov 2005 14:22:44 +0900") Message-ID: <87oe4una9r.fsf@devron.myhome.or.jp> User-Agent: Gnus/5.11 (Gnus v5.11) Emacs/22.0.50 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 8033 Lines: 239 OGAWA Hirofumi writes: >> -int generic_cont_expand(struct inode *inode, loff_t size) >> +static int __generic_cont_expand(struct inode *inode, loff_t size, int dont_do_that) >> { >> struct address_space *mapping = inode->i_mapping; >> struct page *page; >> @@ -2182,9 +2182,8 @@ int generic_cont_expand(struct inode *in >> ** skip the prepare. make sure we never send an offset for the start >> ** of a block >> */ >> - if ((offset & (inode->i_sb->s_blocksize - 1)) == 0) { >> + if (!dont_do_that && (offset & (inode->i_sb->s_blocksize - 1)) == 0) >> offset++; > > Yes. But, if size is the page boundary, index is different. > > Probably something like the below. And I'd like to do vmtruncate() > if ->prepare_write() returns a error. The sync_page_range_nolock() > can do by caller, so not necessary. > > Hmm, I'll rethink this at tonight (10 hours later), the result may be > same after all though. How about this patch? If ok, please replace fat-support-a-truncate-for-expanding-size.patch with this. Thanks. -- OGAWA Hirofumi [PATCH] fat: Support a truncate() for expanding size (generic_cont_expand) This patch changes generic_cont_expand(), in order to share the code with fatfs. - Use vmtruncate() if ->prepare_write() returns a error. Even if ->prepare_write() returns an error, it may already have added some blocks. So, this truncates blocks outside of ->i_size by vmtruncate(). - Add generic_cont_expand_simple(). The generic_cont_expand_simple() assumes that ->prepare_write() can handle the block boundary. With this, we don't need to care the extra byte. And for expanding a file size by truncate(), fatfs uses the added generic_cont_expand_simple(). Signed-off-by: OGAWA Hirofumi --- fs/buffer.c | 60 +++++++++++++++++++++++++++++++++----------- fs/fat/file.c | 31 ++++++++++++++++++++-- include/linux/buffer_head.h | 3 +- 3 files changed, 76 insertions(+), 18 deletions(-) diff -puN fs/fat/file.c~fat_support-expand-truncate fs/fat/file.c --- linux-2.6.14/fs/fat/file.c~fat_support-expand-truncate 2005-11-07 23:03:02.000000000 +0900 +++ linux-2.6.14-hirofumi/fs/fat/file.c 2005-11-09 04:00:53.000000000 +0900 @@ -11,6 +11,7 @@ #include #include #include +#include int fat_generic_ioctl(struct inode *inode, struct file *filp, unsigned int cmd, unsigned long arg) @@ -124,6 +125,24 @@ struct file_operations fat_file_operatio .sendfile = generic_file_sendfile, }; +static int fat_cont_expand(struct inode *inode, loff_t size) +{ + struct address_space *mapping = inode->i_mapping; + loff_t start = inode->i_size, count = size - inode->i_size; + int err; + + err = generic_cont_expand_simple(inode, size); + if (err) + goto out; + + inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC; + mark_inode_dirty(inode); + if (IS_SYNC(inode)) + err = sync_page_range_nolock(inode, mapping, start, count); +out: + return err; +} + int fat_notify_change(struct dentry *dentry, struct iattr *attr) { struct msdos_sb_info *sbi = MSDOS_SB(dentry->d_sb); @@ -132,11 +151,17 @@ int fat_notify_change(struct dentry *den lock_kernel(); - /* FAT cannot truncate to a longer file */ + /* + * Expand the file. Since inode_setattr() updates ->i_size + * before calling the ->truncate(), but FAT needs to fill the + * hole before it. + */ if (attr->ia_valid & ATTR_SIZE) { if (attr->ia_size > inode->i_size) { - error = -EPERM; - goto out; + error = fat_cont_expand(inode, attr->ia_size); + if (error || attr->ia_valid == ATTR_SIZE) + goto out; + attr->ia_valid &= ~ATTR_SIZE; } } diff -puN fs/buffer.c~fat_support-expand-truncate fs/buffer.c --- linux-2.6.14/fs/buffer.c~fat_support-expand-truncate 2005-11-09 03:35:10.000000000 +0900 +++ linux-2.6.14-hirofumi/fs/buffer.c 2005-11-09 04:33:29.000000000 +0900 @@ -2160,11 +2160,12 @@ int block_read_full_page(struct page *pa * truncates. Uses prepare/commit_write to allow the filesystem to * deal with the hole. */ -int generic_cont_expand(struct inode *inode, loff_t size) +static int __generic_cont_expand(struct inode *inode, loff_t size, + pgoff_t index, unsigned int offset) { struct address_space *mapping = inode->i_mapping; struct page *page; - unsigned long index, offset, limit; + unsigned long limit; int err; err = -EFBIG; @@ -2176,24 +2177,24 @@ int generic_cont_expand(struct inode *in if (size > inode->i_sb->s_maxbytes) goto out; - offset = (size & (PAGE_CACHE_SIZE-1)); /* Within page */ - - /* ugh. in prepare/commit_write, if from==to==start of block, we - ** skip the prepare. make sure we never send an offset for the start - ** of a block - */ - if ((offset & (inode->i_sb->s_blocksize - 1)) == 0) { - offset++; - } - index = size >> PAGE_CACHE_SHIFT; err = -ENOMEM; page = grab_cache_page(mapping, index); if (!page) goto out; err = mapping->a_ops->prepare_write(NULL, page, offset, offset); - if (!err) { - err = mapping->a_ops->commit_write(NULL, page, offset, offset); + if (err) { + /* + * ->prepare_write() may have instantiated a few blocks + * outside i_size. Trim these off again. + */ + unlock_page(page); + page_cache_release(page); + vmtruncate(inode, inode->i_size); + goto out; } + + err = mapping->a_ops->commit_write(NULL, page, offset, offset); + unlock_page(page); page_cache_release(page); if (err > 0) @@ -2202,6 +2203,36 @@ out: return err; } +int generic_cont_expand(struct inode *inode, loff_t size) +{ + pgoff_t index; + unsigned int offset; + + offset = (size & (PAGE_CACHE_SIZE - 1)); /* Within page */ + + /* ugh. in prepare/commit_write, if from==to==start of block, we + ** skip the prepare. make sure we never send an offset for the start + ** of a block + */ + if ((offset & (inode->i_sb->s_blocksize - 1)) == 0) { + /* caller must handle this extra byte. */ + offset++; + } + index = size >> PAGE_CACHE_SHIFT; + + return __generic_cont_expand(inode, size, index, offset); +} + +int generic_cont_expand_simple(struct inode *inode, loff_t size) +{ + loff_t pos = size - 1; + pgoff_t index = pos >> PAGE_CACHE_SHIFT; + unsigned int offset = (pos & (PAGE_CACHE_SIZE - 1)) + 1; + + /* prepare/commit_write can handle even if from==to==start of block. */ + return __generic_cont_expand(inode, size, index, offset); +} + /* * For moronic filesystems that do not allow holes in file. * We may have to extend the file. @@ -3145,6 +3176,7 @@ EXPORT_SYMBOL(fsync_bdev); EXPORT_SYMBOL(generic_block_bmap); EXPORT_SYMBOL(generic_commit_write); EXPORT_SYMBOL(generic_cont_expand); +EXPORT_SYMBOL(generic_cont_expand_simple); EXPORT_SYMBOL(init_buffer); EXPORT_SYMBOL(invalidate_bdev); EXPORT_SYMBOL(ll_rw_block); diff -puN include/linux/buffer_head.h~fat_support-expand-truncate include/linux/buffer_head.h --- linux-2.6.14/include/linux/buffer_head.h~fat_support-expand-truncate 2005-11-09 03:37:26.000000000 +0900 +++ linux-2.6.14-hirofumi/include/linux/buffer_head.h 2005-11-09 03:37:36.000000000 +0900 @@ -197,7 +197,8 @@ int block_read_full_page(struct page*, g int block_prepare_write(struct page*, unsigned, unsigned, get_block_t*); int cont_prepare_write(struct page*, unsigned, unsigned, get_block_t*, loff_t *); -int generic_cont_expand(struct inode *inode, loff_t size) ; +int generic_cont_expand(struct inode *inode, loff_t size); +int generic_cont_expand_simple(struct inode *inode, loff_t size); int block_commit_write(struct page *page, unsigned from, unsigned to); int block_sync_page(struct page *); sector_t generic_block_bmap(struct address_space *, sector_t, get_block_t *); _ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/