From: Joel Becker Date: Tue, 6 Jul 2010 21:36:06 +0000 (-0700) Subject: ocfs2: When zero extending, do it by page. X-Git-Url: http://git.cdn.openwrt.org/?a=commitdiff_plain;h=a4bfb4cf11fd2211b788af59dc8a8b4394bca227;p=openwrt%2Fstaging%2Fblogic.git ocfs2: When zero extending, do it by page. ocfs2_zero_extend() does its zeroing block by block, but it calls a function named ocfs2_write_zero_page(). Let's have ocfs2_write_zero_page() handle the page level. From ocfs2_zero_extend()'s perspective, it is now page-at-a-time. Signed-off-by: Joel Becker Cc: stable@kernel.org --- diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c index 3623ca20cc18..9a5c931439bd 100644 --- a/fs/ocfs2/aops.c +++ b/fs/ocfs2/aops.c @@ -459,36 +459,6 @@ int walk_page_buffers( handle_t *handle, return ret; } -handle_t *ocfs2_start_walk_page_trans(struct inode *inode, - struct page *page, - unsigned from, - unsigned to) -{ - struct ocfs2_super *osb = OCFS2_SB(inode->i_sb); - handle_t *handle; - int ret = 0; - - handle = ocfs2_start_trans(osb, OCFS2_INODE_UPDATE_CREDITS); - if (IS_ERR(handle)) { - ret = -ENOMEM; - mlog_errno(ret); - goto out; - } - - if (ocfs2_should_order_data(inode)) { - ret = ocfs2_jbd2_file_inode(handle, inode); - if (ret < 0) - mlog_errno(ret); - } -out: - if (ret) { - if (!IS_ERR(handle)) - ocfs2_commit_trans(osb, handle); - handle = ERR_PTR(ret); - } - return handle; -} - static sector_t ocfs2_bmap(struct address_space *mapping, sector_t block) { sector_t status; diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c index 6a13ea64c447..4cfc976a9067 100644 --- a/fs/ocfs2/file.c +++ b/fs/ocfs2/file.c @@ -724,28 +724,55 @@ leave: return status; } +/* + * While a write will already be ordering the data, a truncate will not. + * Thus, we need to explicitly order the zeroed pages. + */ +static handle_t *ocfs2_zero_start_ordered_transaction(struct inode *inode) +{ + struct ocfs2_super *osb = OCFS2_SB(inode->i_sb); + handle_t *handle = NULL; + int ret = 0; + + if (!ocfs2_should_order_data(inode)) + goto out; + + handle = ocfs2_start_trans(osb, OCFS2_INODE_UPDATE_CREDITS); + if (IS_ERR(handle)) { + ret = -ENOMEM; + mlog_errno(ret); + goto out; + } + + ret = ocfs2_jbd2_file_inode(handle, inode); + if (ret < 0) + mlog_errno(ret); + +out: + if (ret) { + if (!IS_ERR(handle)) + ocfs2_commit_trans(osb, handle); + handle = ERR_PTR(ret); + } + return handle; +} + /* Some parts of this taken from generic_cont_expand, which turned out * to be too fragile to do exactly what we need without us having to * worry about recursive locking in ->write_begin() and ->write_end(). */ -static int ocfs2_write_zero_page(struct inode *inode, - u64 size) +static int ocfs2_write_zero_page(struct inode *inode, u64 abs_from, + u64 abs_to) { struct address_space *mapping = inode->i_mapping; struct page *page; - unsigned long index; - unsigned int offset; + unsigned long index = abs_from >> PAGE_CACHE_SHIFT; handle_t *handle = NULL; int ret; + unsigned zero_from, zero_to, block_start, block_end; - 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; + BUG_ON(abs_from >= abs_to); + BUG_ON(abs_to > (((u64)index + 1) << PAGE_CACHE_SHIFT)); + BUG_ON(abs_from & (inode->i_blkbits - 1)); page = grab_cache_page(mapping, index); if (!page) { @@ -754,31 +781,51 @@ static int ocfs2_write_zero_page(struct inode *inode, goto out; } - ret = ocfs2_prepare_write_nolock(inode, page, offset, offset); - if (ret < 0) { - mlog_errno(ret); - goto out_unlock; - } + /* Get the offsets within the page that we want to zero */ + zero_from = abs_from & (PAGE_CACHE_SIZE - 1); + zero_to = abs_to & (PAGE_CACHE_SIZE - 1); + if (!zero_to) + zero_to = PAGE_CACHE_SIZE; - if (ocfs2_should_order_data(inode)) { - handle = ocfs2_start_walk_page_trans(inode, page, offset, - offset); - if (IS_ERR(handle)) { - ret = PTR_ERR(handle); - handle = NULL; + /* We know that zero_from is block aligned */ + for (block_start = zero_from; block_start < zero_to; + block_start = block_end) { + block_end = block_start + (1 << inode->i_blkbits); + + /* + * block_start is block-aligned. Bump it by one to + * force ocfs2_{prepare,commit}_write() to zero the + * whole block. + */ + ret = ocfs2_prepare_write_nolock(inode, page, + block_start + 1, + block_start + 1); + if (ret < 0) { + mlog_errno(ret); goto out_unlock; } - } - /* must not update i_size! */ - ret = block_commit_write(page, offset, offset); - if (ret < 0) - mlog_errno(ret); - else - ret = 0; + if (!handle) { + handle = ocfs2_zero_start_ordered_transaction(inode); + if (IS_ERR(handle)) { + ret = PTR_ERR(handle); + handle = NULL; + break; + } + } + + /* must not update i_size! */ + ret = block_commit_write(page, block_start + 1, + block_start + 1); + if (ret < 0) + mlog_errno(ret); + else + ret = 0; + } if (handle) ocfs2_commit_trans(OCFS2_SB(inode->i_sb), handle); + out_unlock: unlock_page(page); page_cache_release(page); @@ -790,18 +837,21 @@ static int ocfs2_zero_extend(struct inode *inode, u64 zero_to_size) { int ret = 0; - u64 start_off; + u64 start_off, next_off; struct super_block *sb = inode->i_sb; start_off = ocfs2_align_bytes_to_blocks(sb, i_size_read(inode)); while (start_off < zero_to_size) { - ret = ocfs2_write_zero_page(inode, start_off); + next_off = (start_off & PAGE_CACHE_MASK) + PAGE_CACHE_SIZE; + if (next_off > zero_to_size) + next_off = zero_to_size; + ret = ocfs2_write_zero_page(inode, start_off, next_off); if (ret < 0) { mlog_errno(ret); goto out; } - start_off += sb->s_blocksize; + start_off = next_off; /* * Very large extends have the potential to lock up