From: "Amit K. Arora" Subject: [RFC][Patch 1/1] Persistent preallocation in ext4 Date: Tue, 5 Dec 2006 19:13:38 +0530 Message-ID: <20061205134338.GA1894@amitarora.in.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from e35.co.us.ibm.com ([32.97.110.153]:60304 "EHLO e35.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S968194AbWLENnm (ORCPT ); Tue, 5 Dec 2006 08:43:42 -0500 Received: from westrelay02.boulder.ibm.com (westrelay02.boulder.ibm.com [9.17.195.11]) by e35.co.us.ibm.com (8.13.8/8.12.11) with ESMTP id kB5DhaTq007697 for ; Tue, 5 Dec 2006 08:43:36 -0500 Received: from d03av02.boulder.ibm.com (d03av02.boulder.ibm.com [9.17.195.168]) by westrelay02.boulder.ibm.com (8.13.6/8.13.6/NCO v8.1.1) with ESMTP id kB5DhaTc486868 for ; Tue, 5 Dec 2006 06:43:36 -0700 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 kB5DharY004326 for ; Tue, 5 Dec 2006 06:43:36 -0700 Received: from amitarora.in.ibm.com (amitarora.in.ibm.com [9.124.31.160]) by d03av02.boulder.ibm.com (8.12.11.20060308/8.12.11) with ESMTP id kB5DhYa1004217 for ; Tue, 5 Dec 2006 06:43:35 -0700 Received: from amitarora.in.ibm.com (localhost.localdomain [127.0.0.1]) by amitarora.in.ibm.com (Postfix) with ESMTP id 48F302A041E for ; Tue, 5 Dec 2006 19:13:38 +0530 (IST) Received: (from amit@localhost) by amitarora.in.ibm.com (8.13.1/8.13.1/Submit) id kB5Dhccb002989 for linux-ext4@vger.kernel.org; Tue, 5 Dec 2006 19:13:38 +0530 To: linux-ext4@vger.kernel.org Content-Disposition: inline Sender: linux-ext4-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org This patch implements persistent preallocation using ioctl. Other options under consideration are posix_fallocate and ftruncate. The code can be ported to other approach, if ioctl is not the favored one. The patch takes care of marking/checking uninitialized extents. Signed-off-by: Amit Arora --- fs/ext4/extents.c | 120 ++++++++++++++++++++++++++++++++---------------- fs/ext4/ioctl.c | 41 ++++++++++++++++ include/linux/ext4_fs.h | 21 ++++++++ 3 files changed, 144 insertions(+), 38 deletions(-) Index: linux-2.6.19/fs/ext4/extents.c =================================================================== --- linux-2.6.19.orig/fs/ext4/extents.c 2006-12-05 16:03:40.000000000 +0530 +++ linux-2.6.19/fs/ext4/extents.c 2006-12-05 16:03:53.000000000 +0530 @@ -282,7 +282,7 @@ } else if (path->p_ext) { ext_debug(" %d:%d:%llu ", le32_to_cpu(path->p_ext->ee_block), - le16_to_cpu(path->p_ext->ee_len), + ext4_ext_get_actual_len(path->p_ext), ext_pblock(path->p_ext)); } else ext_debug(" []"); @@ -305,7 +305,7 @@ for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ex++) { ext_debug("%d:%d:%llu ", le32_to_cpu(ex->ee_block), - le16_to_cpu(ex->ee_len), ext_pblock(ex)); + ext4_ext_get_actual_len(ex), ext_pblock(ex)); } ext_debug("\n"); } @@ -425,7 +425,7 @@ ext_debug(" -> %d:%llu:%d ", le32_to_cpu(path->p_ext->ee_block), ext_pblock(path->p_ext), - le16_to_cpu(path->p_ext->ee_len)); + ext4_ext_get_actual_len(path->p_ext)); #ifdef CHECK_BINSEARCH { @@ -686,7 +686,7 @@ ext_debug("move %d:%llu:%d in new leaf %llu\n", le32_to_cpu(path[depth].p_ext->ee_block), ext_pblock(path[depth].p_ext), - le16_to_cpu(path[depth].p_ext->ee_len), + ext4_ext_get_actual_len(path[depth].p_ext), newblock); /*memmove(ex++, path[depth].p_ext++, sizeof(struct ext4_extent)); @@ -1097,7 +1097,23 @@ ext4_can_extents_be_merged(struct inode *inode, struct ext4_extent *ex1, struct ext4_extent *ex2) { - if (le32_to_cpu(ex1->ee_block) + le16_to_cpu(ex1->ee_len) != + unsigned short ext1_ee_len, ext2_ee_len; + + + /* + * Make sure that either both extents are uninitialized, or + * both are _not_. + */ + if ((ext4_ext_is_uninitialized(ex1) + && !ext4_ext_is_uninitialized(ex2)) + || (!ext4_ext_is_uninitialized(ex1) + && ext4_ext_is_uninitialized(ex2))) + return 0; + + ext1_ee_len = ext4_ext_get_actual_len(ex1); + ext2_ee_len = ext4_ext_get_actual_len(ex2); + + if (le32_to_cpu(ex1->ee_block) + ext1_ee_len != le32_to_cpu(ex2->ee_block)) return 0; @@ -1106,14 +1122,14 @@ * as an RO_COMPAT feature, refuse to merge to extents if * this can result in the top bit of ee_len being set. */ - if (le16_to_cpu(ex1->ee_len) + le16_to_cpu(ex2->ee_len) > EXT_MAX_LEN) + if (ext1_ee_len + ext2_ee_len > EXT_MAX_LEN) return 0; #ifdef AGRESSIVE_TEST if (le16_to_cpu(ex1->ee_len) >= 4) return 0; #endif - if (ext_pblock(ex1) + le16_to_cpu(ex1->ee_len) == ext_pblock(ex2)) + if (ext_pblock(ex1) + ext1_ee_len == ext_pblock(ex2)) return 1; return 0; } @@ -1132,9 +1148,9 @@ struct ext4_extent *ex, *fex; struct ext4_extent *nearex; /* nearest extent */ struct ext4_ext_path *npath = NULL; - int depth, len, err, next; + int depth, len, err, next, uninitialized = 0; - BUG_ON(newext->ee_len == 0); + BUG_ON(ext4_ext_get_actual_len(newext) == 0); depth = ext_depth(inode); ex = path[depth].p_ext; BUG_ON(path[depth].p_hdr == NULL); @@ -1142,13 +1158,22 @@ /* try to insert block into found extent and return */ if (ex && ext4_can_extents_be_merged(inode, ex, newext)) { ext_debug("append %d block to %d:%d (from %llu)\n", - le16_to_cpu(newext->ee_len), + ext4_ext_get_actual_len(newext), le32_to_cpu(ex->ee_block), - le16_to_cpu(ex->ee_len), ext_pblock(ex)); + ext4_ext_get_actual_len(ex), ext_pblock(ex)); if ((err = ext4_ext_get_access(handle, inode, path + depth))) return err; - ex->ee_len = cpu_to_le16(le16_to_cpu(ex->ee_len) - + le16_to_cpu(newext->ee_len)); + + /* ext4_can_extents_be_merged should have checked that either + * both extents are uninitialized, or both aren't. Thus we + * need to check any of them here. + */ + if (ext4_ext_is_uninitialized(ex)) + uninitialized = 1; + ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex) + + ext4_ext_get_actual_len(newext)); + if(uninitialized) + ext4_mark_uninitialized_ext(ex); eh = path[depth].p_hdr; nearex = ex; goto merge; @@ -1203,7 +1228,7 @@ ext_debug("first extent in the leaf: %d:%llu:%d\n", le32_to_cpu(newext->ee_block), ext_pblock(newext), - le16_to_cpu(newext->ee_len)); + ext4_mark_uninitialized_ext(newext)); path[depth].p_ext = EXT_FIRST_EXTENT(eh); } else if (le32_to_cpu(newext->ee_block) > le32_to_cpu(nearex->ee_block)) { @@ -1216,7 +1241,7 @@ "move %d from 0x%p to 0x%p\n", le32_to_cpu(newext->ee_block), ext_pblock(newext), - le16_to_cpu(newext->ee_len), + ext4_mark_uninitialized_ext(newext), nearex, len, nearex + 1, nearex + 2); memmove(nearex + 2, nearex + 1, len); } @@ -1229,7 +1254,7 @@ "move %d from 0x%p to 0x%p\n", le32_to_cpu(newext->ee_block), ext_pblock(newext), - le16_to_cpu(newext->ee_len), + ext4_ext_get_actual_len(newext), nearex, len, nearex + 1, nearex + 2); memmove(nearex + 1, nearex, len); path[depth].p_ext = nearex; @@ -1248,8 +1273,13 @@ if (!ext4_can_extents_be_merged(inode, nearex, nearex + 1)) break; /* merge with next extent! */ - nearex->ee_len = cpu_to_le16(le16_to_cpu(nearex->ee_len) - + le16_to_cpu(nearex[1].ee_len)); + if (ext4_ext_is_uninitialized(nearex)) + uninitialized = 1; + nearex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(nearex) + + ext4_ext_get_actual_len(nearex + 1)); + if(uninitialized) + ext4_mark_uninitialized_ext(nearex); + if (nearex + 1 < EXT_LAST_EXTENT(eh)) { len = (EXT_LAST_EXTENT(eh) - nearex - 1) * sizeof(struct ext4_extent); @@ -1319,8 +1349,8 @@ end = le32_to_cpu(ex->ee_block); if (block + num < end) end = block + num; - } else if (block >= - le32_to_cpu(ex->ee_block) + le16_to_cpu(ex->ee_len)) { + } else if (block >= le32_to_cpu(ex->ee_block) + + ext4_ext_get_actual_len(ex)) { /* need to allocate space after found extent */ start = block; end = block + num; @@ -1332,7 +1362,8 @@ * by found extent */ start = block; - end = le32_to_cpu(ex->ee_block) + le16_to_cpu(ex->ee_len); + end = le32_to_cpu(ex->ee_block) + + ext4_ext_get_actual_len(ex); if (block + num < end) end = block + num; exists = 1; @@ -1348,7 +1379,7 @@ cbex.ec_type = EXT4_EXT_CACHE_GAP; } else { cbex.ec_block = le32_to_cpu(ex->ee_block); - cbex.ec_len = le16_to_cpu(ex->ee_len); + cbex.ec_len = ext4_ext_get_actual_len(ex); cbex.ec_start = ext_pblock(ex); cbex.ec_type = EXT4_EXT_CACHE_EXTENT; } @@ -1556,12 +1587,12 @@ unsigned long from, unsigned long to) { struct buffer_head *bh; + unsigned short ee_len = ext4_ext_get_actual_len(ex); int i; #ifdef EXTENTS_STATS { struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); - unsigned short ee_len = le16_to_cpu(ex->ee_len); spin_lock(&sbi->s_ext_stats_lock); sbi->s_ext_blocks += ee_len; sbi->s_ext_extents++; @@ -1575,12 +1606,12 @@ } #endif if (from >= le32_to_cpu(ex->ee_block) - && to == le32_to_cpu(ex->ee_block) + le16_to_cpu(ex->ee_len) - 1) { + && to == le32_to_cpu(ex->ee_block) + ee_len - 1) { /* tail removal */ unsigned long num; ext4_fsblk_t start; - num = le32_to_cpu(ex->ee_block) + le16_to_cpu(ex->ee_len) - from; - start = ext_pblock(ex) + le16_to_cpu(ex->ee_len) - num; + num = le32_to_cpu(ex->ee_block) + ee_len - from; + start = ext_pblock(ex) + ee_len - num; ext_debug("free last %lu blocks starting %llu\n", num, start); for (i = 0; i < num; i++) { bh = sb_find_get_block(inode->i_sb, start + i); @@ -1588,12 +1619,12 @@ } ext4_free_blocks(handle, inode, start, num); } else if (from == le32_to_cpu(ex->ee_block) - && to <= le32_to_cpu(ex->ee_block) + le16_to_cpu(ex->ee_len) - 1) { + && to <= le32_to_cpu(ex->ee_block) + ee_len - 1) { printk("strange request: removal %lu-%lu from %u:%u\n", - from, to, le32_to_cpu(ex->ee_block), le16_to_cpu(ex->ee_len)); + from, to, le32_to_cpu(ex->ee_block), ee_len); } else { printk("strange request: removal(2) %lu-%lu from %u:%u\n", - from, to, le32_to_cpu(ex->ee_block), le16_to_cpu(ex->ee_len)); + from, to, le32_to_cpu(ex->ee_block), ee_len); } return 0; } @@ -1607,7 +1638,7 @@ struct ext4_extent_header *eh; unsigned a, b, block, num; unsigned long ex_ee_block; - unsigned short ex_ee_len; + unsigned short ex_ee_len, uninitialized = 0; struct ext4_extent *ex; ext_debug("truncate since %lu in leaf\n", start); @@ -1622,7 +1653,9 @@ ex = EXT_LAST_EXTENT(eh); ex_ee_block = le32_to_cpu(ex->ee_block); - ex_ee_len = le16_to_cpu(ex->ee_len); + if(ext4_ext_is_uninitialized(ex)) + uninitialized = 1; + ex_ee_len = ext4_ext_get_actual_len(ex); while (ex >= EXT_FIRST_EXTENT(eh) && ex_ee_block + ex_ee_len > start) { @@ -1690,6 +1723,8 @@ ex->ee_block = cpu_to_le32(block); ex->ee_len = cpu_to_le16(num); + if(uninitialized) + ext4_mark_uninitialized_ext(ex); err = ext4_ext_dirty(handle, inode, path + depth); if (err) @@ -1699,7 +1734,7 @@ ext_pblock(ex)); ex--; ex_ee_block = le32_to_cpu(ex->ee_block); - ex_ee_len = le16_to_cpu(ex->ee_len); + ex_ee_len = ext4_ext_get_actual_len(ex); } if (correct_index && eh->eh_entries) @@ -1974,7 +2009,7 @@ if ((ex = path[depth].p_ext)) { unsigned long ee_block = le32_to_cpu(ex->ee_block); ext4_fsblk_t ee_start = ext_pblock(ex); - unsigned short ee_len = le16_to_cpu(ex->ee_len); + unsigned short ee_len; /* * Allow future support for preallocated extents to be added @@ -1982,8 +2017,11 @@ * Uninitialized extents are treated as holes, except that * we avoid (fail) allocating new blocks during a write. */ - if (ee_len > EXT_MAX_LEN) + if (le16_to_cpu(ex->ee_len) > EXT_MAX_LEN + && create != EXT4_CREATE_UNINITIALIZED_EXT) goto out2; + + ee_len = ext4_ext_get_actual_len(ex); /* if found extent covers block, simply return it */ if (iblock >= ee_block && iblock < ee_block + ee_len) { newblock = iblock - ee_block + ee_start; @@ -1991,8 +2029,10 @@ allocated = ee_len - (iblock - ee_block); ext_debug("%d fit into %lu:%d -> %llu\n", (int) iblock, ee_block, ee_len, newblock); - ext4_ext_put_in_cache(inode, ee_block, ee_len, - ee_start, EXT4_EXT_CACHE_EXTENT); + /* Do not put uninitialized extent in the cache */ + if(!ext4_ext_is_uninitialized(ex)) + ext4_ext_put_in_cache(inode, ee_block, ee_len, + ee_start, EXT4_EXT_CACHE_EXTENT); goto out; } } @@ -2027,6 +2067,8 @@ newex.ee_block = cpu_to_le32(iblock); ext4_ext_store_pblock(&newex, newblock); newex.ee_len = cpu_to_le16(allocated); + if(create == EXT4_CREATE_UNINITIALIZED_EXT) /* Mark uninitialized */ + ext4_mark_uninitialized_ext(&newex); err = ext4_ext_insert_extent(handle, inode, path, &newex); if (err) goto out2; @@ -2038,8 +2080,10 @@ newblock = ext_pblock(&newex); __set_bit(BH_New, &bh_result->b_state); - ext4_ext_put_in_cache(inode, iblock, allocated, newblock, - EXT4_EXT_CACHE_EXTENT); + /* Cache only when it is _not_ an uninitialized extent */ + if(create!=EXT4_CREATE_UNINITIALIZED_EXT) + ext4_ext_put_in_cache(inode, iblock, allocated, newblock, + EXT4_EXT_CACHE_EXTENT); out: if (allocated > max_blocks) allocated = max_blocks; Index: linux-2.6.19/fs/ext4/ioctl.c =================================================================== --- linux-2.6.19.orig/fs/ext4/ioctl.c 2006-12-05 16:03:40.000000000 +0530 +++ linux-2.6.19/fs/ext4/ioctl.c 2006-12-05 16:03:43.000000000 +0530 @@ -248,6 +248,47 @@ return err; } + case EXT4_IOC_PREALLOCATE: { + struct ext4_falloc_input input; + handle_t *handle; + ext4_fsblk_t block, max_blocks; + int ret = 0; + struct buffer_head map_bh; + unsigned int blkbits = inode->i_blkbits; + + if (IS_RDONLY(inode)) + return -EROFS; + + if (copy_from_user(&input, + (struct ext4_falloc_input __user *) arg, sizeof(input))) + return -EFAULT; + + if (input.len == 0) + return -EINVAL; + + if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)) + return -ENOTTY; + + block = EXT4_BLOCK_ALIGN(input.offset, blkbits) >> blkbits; + max_blocks = EXT4_BLOCK_ALIGN(input.len, blkbits) >> blkbits; + handle=ext4_journal_start(inode, + EXT4_DATA_TRANS_BLOCKS(inode->i_sb)+max_blocks); + if (IS_ERR(handle)) + return PTR_ERR(handle); + while(ret>=0 && ret0?0:ret; + } + default: return -ENOTTY; } Index: linux-2.6.19/include/linux/ext4_fs.h =================================================================== --- linux-2.6.19.orig/include/linux/ext4_fs.h 2006-12-05 16:03:40.000000000 +0530 +++ linux-2.6.19/include/linux/ext4_fs.h 2006-12-05 16:03:53.000000000 +0530 @@ -102,6 +102,8 @@ EXT4_GOOD_OLD_FIRST_INO : \ (s)->s_first_ino) #endif +#define EXT4_BLOCK_ALIGN(size, blkbits) (((size)+(1 << blkbits)-1) & \ + (~((1 << blkbits)-1))) /* * Macro-instructions used to manage fragments @@ -118,6 +120,19 @@ #endif /* + * Macro-instructions used to handle (mark/unmark/check/create) unitialized + * extents. Applications can issue an IOCTL for preallocation, which results + * in assigning unitialized extents to the file + */ +#define EXT4_CREATE_UNINITIALIZED_EXT 2 +#define ext4_mark_uninitialized_ext(ext) ((ext)->ee_len |= \ + cpu_to_le16(0x8000)) +#define ext4_ext_is_uninitialized(ext) ((le16_to_cpu((ext)->ee_len))& \ + 0x8000) +#define ext4_ext_get_actual_len(ext) ((le16_to_cpu((ext)->ee_len))& \ + 0x7FFF) + +/* * Structure of a blocks group descriptor */ struct ext4_group_desc @@ -225,6 +240,11 @@ __u32 free_blocks_count; }; +/* The struct ext4_falloc_input in kernel, for EXT4_IOC_PREALLOCATE */ +struct ext4_falloc_input { + __u64 offset; + __u64 len; +}; /* * ioctl commands @@ -242,6 +262,7 @@ #endif #define EXT4_IOC_GETRSVSZ _IOR('f', 5, long) #define EXT4_IOC_SETRSVSZ _IOW('f', 6, long) +#define EXT4_IOC_PREALLOCATE _IOW('f', 9, struct ext4_falloc_input) /* * ioctl commands in 32 bit emulation