From: Mingming Cao Subject: [PATCH 3/6 ]Ext4: journal credits reservation fixes for DIO, fallocate Date: Tue, 12 Aug 2008 09:29:50 -0700 Message-ID: <1218558590.6766.47.camel@mingming-laptop> References: <48841077.500@cse.unsw.edu.au> <20080721082010.GC8788@skywalker> <1216774311.6505.4.camel@mingming-laptop> <20080723074226.GA15091@skywalker> <1217032947.6394.2.camel@mingming-laptop> <1218558190.6766.37.camel@mingming-laptop> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Cc: linux-ext4@vger.kernel.org, "Aneesh Kumar K.V" , Andreas Dilger To: tytso Return-path: Received: from e36.co.us.ibm.com ([32.97.110.154]:58396 "EHLO e36.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750899AbYHLQaM (ORCPT ); Tue, 12 Aug 2008 12:30:12 -0400 Received: from d03relay02.boulder.ibm.com (d03relay02.boulder.ibm.com [9.17.195.227]) by e36.co.us.ibm.com (8.13.8/8.13.8) with ESMTP id m7CGUC8T017619 for ; Tue, 12 Aug 2008 12:30:12 -0400 Received: from d03av02.boulder.ibm.com (d03av02.boulder.ibm.com [9.17.195.168]) by d03relay02.boulder.ibm.com (8.13.8/8.13.8/NCO v9.0) with ESMTP id m7CGUBak158334 for ; Tue, 12 Aug 2008 10:30:11 -0600 Received: from d03av02.boulder.ibm.com (loopback [127.0.0.1]) by d03av02.boulder.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id m7CGUARt028464 for ; Tue, 12 Aug 2008 10:30:11 -0600 In-Reply-To: <1218558190.6766.37.camel@mingming-laptop> Sender: linux-ext4-owner@vger.kernel.org List-ID: Ext4: journal credits reservation fixes for DIO, fallocate From: Mingming Cao DIO and fallocate credit calculation is different than writepage, as they do start a new journal right for each call to ext4_get_blocks_wrap(). This patch uses the helper function in DIO and fallocate case, passing a flag indicating that the modified data are contiguous thus could account less indirect/index blocks. This patch also fixed the journal credit reservation for direct I/O (DIO). Previously the estimated credits for DIO only was calculated for non-extent files, which was not enough if the file is extent-based. Also fixed was fallocate double-counting credits for modifying the the superblock. Signed-off-by: Mingming Cao --- --- fs/ext4/ext4.h | 1 + fs/ext4/extents.c | 7 +++---- fs/ext4/inode.c | 49 ++++++++++++++++++++++++++++--------------------- 3 files changed, 32 insertions(+), 25 deletions(-) =================================================================== Index: linux-2.6.27-rc1/fs/ext4/extents.c =================================================================== --- linux-2.6.27-rc1.orig/fs/ext4/extents.c 2008-08-11 22:25:39.000000000 -0700 +++ linux-2.6.27-rc1/fs/ext4/extents.c 2008-08-11 22:25:55.000000000 -0700 @@ -2799,7 +2799,7 @@ void ext4_ext_truncate(struct inode *ino /* * probably first extent we're gonna free will be last in block */ - err = ext4_writepage_trans_blocks(inode) + 3; + err = ext4_writepage_trans_blocks(inode); handle = ext4_journal_start(inode, err); if (IS_ERR(handle)) return; @@ -2951,10 +2951,9 @@ long ext4_fallocate(struct inode *inode, max_blocks = (EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits) - block; /* - * credits to insert 1 extent into extent tree + buffers to be able to - * modify 1 super block, 1 block bitmap and 1 group descriptor. + * credits to insert 1 extent into extent tree */ - credits = EXT4_DATA_TRANS_BLOCKS(inode->i_sb) + 3; + credits = ext4_data_trans_blocks(inode, max_blocks); mutex_lock(&inode->i_mutex); retry: while (ret >= 0 && ret < max_blocks) { Index: linux-2.6.27-rc1/fs/ext4/inode.c =================================================================== --- linux-2.6.27-rc1.orig/fs/ext4/inode.c 2008-08-11 22:18:31.000000000 -0700 +++ linux-2.6.27-rc1/fs/ext4/inode.c 2008-08-11 22:25:55.000000000 -0700 @@ -1041,18 +1041,6 @@ static void ext4_da_update_reserve_space spin_unlock(&EXT4_I(inode)->i_block_reservation_lock); } -/* Maximum number of blocks we map for direct IO at once. */ -#define DIO_MAX_BLOCKS 4096 -/* - * Number of credits we need for writing DIO_MAX_BLOCKS: - * We need sb + group descriptor + bitmap + inode -> 4 - * For B blocks with A block pointers per block we need: - * 1 (triple ind.) + (B/A/A + 2) (doubly ind.) + (B/A + 2) (indirect). - * If we plug in 4096 for B and 256 for A (for 1KB block size), we get 25. - */ -#define DIO_CREDITS 25 - - /* * The ext4_get_blocks_wrap() function try to look up the requested blocks, * and returns if the blocks are already mapped. @@ -1164,19 +1152,23 @@ int ext4_get_blocks_wrap(handle_t *handl return retval; } +/* Maximum number of blocks we map for direct IO at once. */ +#define DIO_MAX_BLOCKS 4096 + static int ext4_get_block(struct inode *inode, sector_t iblock, struct buffer_head *bh_result, int create) { handle_t *handle = ext4_journal_current_handle(); int ret = 0, started = 0; unsigned max_blocks = bh_result->b_size >> inode->i_blkbits; + int dio_credits; if (create && !handle) { /* Direct IO write... */ if (max_blocks > DIO_MAX_BLOCKS) max_blocks = DIO_MAX_BLOCKS; - handle = ext4_journal_start(inode, DIO_CREDITS + - 2 * EXT4_QUOTA_TRANS_BLOCKS(inode->i_sb)); + dio_credits = ext4_data_trans_blocks(inode, max_blocks); + handle = ext4_journal_start(inode, dio_credits); if (IS_ERR(handle)) { ret = PTR_ERR(handle); goto out; @@ -2222,7 +2214,7 @@ static int ext4_da_writepage(struct page * for DIO, writepages, and truncate */ #define EXT4_MAX_WRITEBACK_PAGES DIO_MAX_BLOCKS -#define EXT4_MAX_WRITEBACK_CREDITS DIO_CREDITS +#define EXT4_MAX_WRITEBACK_CREDITS 25 static int ext4_da_writepages(struct address_space *mapping, struct writeback_control *wbc) @@ -4429,7 +4421,8 @@ static int ext4_writeblocks_trans_credit /* * Calulate the total number of credits to reserve to fit - * the modification of a single pages into a single transaction + * the modification of a single pages into a single transaction, + * which may include multile chunk of block allocations. * * This could be called via ext4_write_begin() or later * ext4_da_writepages() in delalyed allocation case. @@ -4437,11 +4430,6 @@ static int ext4_writeblocks_trans_credit * In both case it's possible that we could allocating multiple * chunks of blocks. We need to consider the worse case, when * one new block per extent. - * - * For Direct IO and fallocate, the journal credits reservation - * is based on one single extent allocation, so they could use - * EXT4_DATA_TRANS_BLOCKS to get the needed credit to log a single - * chunk of allocation needs. */ int ext4_writepage_trans_blocks(struct inode *inode) { @@ -4451,6 +4439,25 @@ int ext4_writepage_trans_blocks(struct i return ext4_writeblocks_trans_credits_old(inode, bpp, 0); return ext4_ext_writepage_trans_blocks(inode, bpp, 0); } + +/* + * Calculate the journal credits for a chunk of data modification. + * + * For Direct IO and fallocate, the journal credits reservation + * is based on one single extent allocation, so they could use + * this function to get the needed credit to log a single + * chunk of allocation needs. + * + * This is called from DIO, fallocate or whoever calling + * ext4_get_blocks_wrap() to map/allocate a chunk of contigous disk blocks + */ +int ext4_data_trans_blocks(struct inode *inode, int nrblocks) +{ + if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)) + return ext4_writeblocks_trans_credits_old(inode, nrblocks, 1); + return ext4_ext_writepage_trans_blocks(inode, nrblocks, 1); +} + /* * The caller must have previously called ext4_reserve_inode_write(). * Give this, we know that the caller already has write access to iloc->bh. Index: linux-2.6.27-rc1/fs/ext4/ext4.h =================================================================== --- linux-2.6.27-rc1.orig/fs/ext4/ext4.h 2008-08-11 22:18:31.000000000 -0700 +++ linux-2.6.27-rc1/fs/ext4/ext4.h 2008-08-11 22:25:55.000000000 -0700 @@ -1073,6 +1073,7 @@ extern void ext4_get_inode_flags(struct extern void ext4_set_aops(struct inode *inode); extern int ext4_writepage_trans_blocks(struct inode *); extern int ext4_meta_trans_blocks(struct inode *, int nrblocks, int idxblocks); +extern int ext4_data_trans_blocks(struct inode *, int nrblocks); extern int ext4_block_truncate_page(handle_t *handle, struct address_space *mapping, loff_t from); extern int ext4_page_mkwrite(struct vm_area_struct *vma, struct page *page);