From 2f8e0a7c6c89f850ebd5d6c0b9a08317030d1b89 Mon Sep 17 00:00:00 2001 From: Zheng Liu Date: Tue, 25 Nov 2014 11:44:37 -0500 Subject: ext4: cache extent hole in extent status tree for ext4_da_map_blocks() Currently extent status tree doesn't cache extent hole when a write looks up in extent tree to make sure whether a block has been allocated or not. In this case, we don't put extent hole in extent cache because later this extent might be removed and a new delayed extent might be added back. But it will cause a defect when we do a lot of writes. If we don't put extent hole in extent cache, the following writes also need to access extent tree to look at whether or not a block has been allocated. It brings a cache miss. This commit fixes this defect. Also if the inode doesn't have any extent, this extent hole will be cached as well. Cc: Andreas Dilger Signed-off-by: Zheng Liu Signed-off-by: Jan Kara Signed-off-by: Theodore Ts'o --- fs/ext4/ext4.h | 4 +--- fs/ext4/extents.c | 31 ++++++++++++++++--------------- fs/ext4/inode.c | 6 ++---- 3 files changed, 19 insertions(+), 22 deletions(-) (limited to 'fs/ext4') diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index 7b3f3b1decff..98da4cda9d18 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -556,10 +556,8 @@ enum { #define EXT4_GET_BLOCKS_KEEP_SIZE 0x0080 /* Do not take i_data_sem locking in ext4_map_blocks */ #define EXT4_GET_BLOCKS_NO_LOCK 0x0100 - /* Do not put hole in extent cache */ -#define EXT4_GET_BLOCKS_NO_PUT_HOLE 0x0200 /* Convert written extents to unwritten */ -#define EXT4_GET_BLOCKS_CONVERT_UNWRITTEN 0x0400 +#define EXT4_GET_BLOCKS_CONVERT_UNWRITTEN 0x0200 /* * The bit position of these flags must not overlap with any of the diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index 7ef2f11aca56..1ee24d74270f 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -2306,16 +2306,16 @@ ext4_ext_put_gap_in_cache(struct inode *inode, struct ext4_ext_path *path, ext4_lblk_t block) { int depth = ext_depth(inode); - unsigned long len = 0; - ext4_lblk_t lblock = 0; + ext4_lblk_t len; + ext4_lblk_t lblock; struct ext4_extent *ex; + struct extent_status es; ex = path[depth].p_ext; if (ex == NULL) { - /* - * there is no extent yet, so gap is [0;-] and we - * don't cache it - */ + /* there is no extent yet, so gap is [0;-] */ + lblock = 0; + len = EXT_MAX_BLOCKS; ext_debug("cache gap(whole file):"); } else if (block < le32_to_cpu(ex->ee_block)) { lblock = block; @@ -2324,9 +2324,6 @@ ext4_ext_put_gap_in_cache(struct inode *inode, struct ext4_ext_path *path, block, le32_to_cpu(ex->ee_block), ext4_ext_get_actual_len(ex)); - if (!ext4_find_delalloc_range(inode, lblock, lblock + len - 1)) - ext4_es_insert_extent(inode, lblock, len, ~0, - EXTENT_STATUS_HOLE); } else if (block >= le32_to_cpu(ex->ee_block) + ext4_ext_get_actual_len(ex)) { ext4_lblk_t next; @@ -2340,14 +2337,19 @@ ext4_ext_put_gap_in_cache(struct inode *inode, struct ext4_ext_path *path, block); BUG_ON(next == lblock); len = next - lblock; - if (!ext4_find_delalloc_range(inode, lblock, lblock + len - 1)) - ext4_es_insert_extent(inode, lblock, len, ~0, - EXTENT_STATUS_HOLE); } else { BUG(); } - ext_debug(" -> %u:%lu\n", lblock, len); + ext4_es_find_delayed_extent_range(inode, lblock, lblock + len - 1, &es); + if (es.es_len) { + /* There's delayed extent containing lblock? */ + if (es.es_lblk <= lblock) + return; + len = min(es.es_lblk - lblock, len); + } + ext_debug(" -> %u:%u\n", lblock, len); + ext4_es_insert_extent(inode, lblock, len, ~0, EXTENT_STATUS_HOLE); } /* @@ -4368,8 +4370,7 @@ int ext4_ext_map_blocks(handle_t *handle, struct inode *inode, * put just found gap into cache to speed up * subsequent requests */ - if ((flags & EXT4_GET_BLOCKS_NO_PUT_HOLE) == 0) - ext4_ext_put_gap_in_cache(inode, path, map->m_lblk); + ext4_ext_put_gap_in_cache(inode, path, map->m_lblk); goto out2; } diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 2315e45161ee..d5a46a8df70b 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -1432,11 +1432,9 @@ static int ext4_da_map_blocks(struct inode *inode, sector_t iblock, if (ext4_has_inline_data(inode)) retval = 0; else if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) - retval = ext4_ext_map_blocks(NULL, inode, map, - EXT4_GET_BLOCKS_NO_PUT_HOLE); + retval = ext4_ext_map_blocks(NULL, inode, map, 0); else - retval = ext4_ind_map_blocks(NULL, inode, map, - EXT4_GET_BLOCKS_NO_PUT_HOLE); + retval = ext4_ind_map_blocks(NULL, inode, map, 0); add_delayed: if (retval == 0) { -- cgit v1.2.3