From 744692dc059845b2a3022119871846e74d4f6e11 Mon Sep 17 00:00:00 2001 From: Jiaying Zhang Date: Thu, 4 Mar 2010 16:14:02 -0500 Subject: ext4: use ext4_get_block_write in buffer write Allocate uninitialized extent before ext4 buffer write and convert the extent to initialized after io completes. The purpose is to make sure an extent can only be marked initialized after it has been written with new data so we can safely drop the i_mutex lock in ext4 DIO read without exposing stale data. This helps to improve multi-thread DIO read performance on high-speed disks. Skip the nobh and data=journal mount cases to make things simple for now. Signed-off-by: Jiaying Zhang Signed-off-by: "Theodore Ts'o" --- fs/ext4/extents.c | 22 ++++++++++++---------- 1 file changed, 12 insertions(+), 10 deletions(-) (limited to 'fs/ext4/extents.c') diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index 90ba8d9df697..c7f166ab50eb 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -1619,7 +1619,7 @@ int ext4_ext_insert_extent(handle_t *handle, struct inode *inode, BUG_ON(path[depth].p_hdr == NULL); /* try to insert block into found extent and return */ - if (ex && (flag != EXT4_GET_BLOCKS_PRE_IO) + if (ex && !(flag & EXT4_GET_BLOCKS_PRE_IO) && ext4_can_extents_be_merged(inode, ex, newext)) { ext_debug("append [%d]%d block to %d:[%d]%d (from %llu)\n", ext4_ext_is_uninitialized(newext), @@ -1740,7 +1740,7 @@ has_space: merge: /* try to merge extents to the right */ - if (flag != EXT4_GET_BLOCKS_PRE_IO) + if (!(flag & EXT4_GET_BLOCKS_PRE_IO)) ext4_ext_try_to_merge(inode, path, nearex); /* try to merge extents to the left */ @@ -3065,7 +3065,7 @@ ext4_ext_handle_uninitialized_extents(handle_t *handle, struct inode *inode, ext4_ext_show_leaf(inode, path); /* get_block() before submit the IO, split the extent */ - if (flags == EXT4_GET_BLOCKS_PRE_IO) { + if ((flags & EXT4_GET_BLOCKS_PRE_IO)) { ret = ext4_split_unwritten_extents(handle, inode, path, iblock, max_blocks, flags); @@ -3078,10 +3078,12 @@ ext4_ext_handle_uninitialized_extents(handle_t *handle, struct inode *inode, io->flag = EXT4_IO_UNWRITTEN; else ext4_set_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN); + if (ext4_should_dioread_nolock(inode)) + set_buffer_uninit(bh_result); goto out; } /* IO end_io complete, convert the filled extent to written */ - if (flags == EXT4_GET_BLOCKS_CONVERT) { + if ((flags & EXT4_GET_BLOCKS_CONVERT)) { ret = ext4_convert_unwritten_extents_endio(handle, inode, path); if (ret >= 0) @@ -3351,21 +3353,21 @@ int ext4_ext_get_blocks(handle_t *handle, struct inode *inode, if (flags & EXT4_GET_BLOCKS_UNINIT_EXT){ ext4_ext_mark_uninitialized(&newex); /* - * io_end structure was created for every async - * direct IO write to the middle of the file. - * To avoid unecessary convertion for every aio dio rewrite - * to the mid of file, here we flag the IO that is really - * need the convertion. + * io_end structure was created for every IO write to an + * uninitialized extent. To avoid unecessary conversion, + * here we flag the IO that really needs the conversion. * For non asycn direct IO case, flag the inode state * that we need to perform convertion when IO is done. */ - if (flags == EXT4_GET_BLOCKS_PRE_IO) { + if ((flags & EXT4_GET_BLOCKS_PRE_IO)) { if (io) io->flag = EXT4_IO_UNWRITTEN; else ext4_set_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN); } + if (ext4_should_dioread_nolock(inode)) + set_buffer_uninit(bh_result); } if (unlikely(EXT4_I(inode)->i_flags & EXT4_EOFBLOCKS_FL)) { -- cgit v1.2.2