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authorFengguang Wu <wfg@mail.ustc.edu.cn>2007-07-19 01:48:04 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-07-19 10:04:44 -0700
commitdc7868fcb9a73990e6f30371c1be465c436a7a7f (patch)
tree21dfd3e625bb4a9f78a7795f0a5b110c3dd8843e /fs/ext4
parenta08a166fe77d9f9ad88ed6d06b97e73453661f89 (diff)
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readahead: convert ext3/ext4 invocations
Convert ext3/ext4 dir reads to use on-demand readahead. Readahead for dirs operates _not_ on file level, but on blockdev level. This makes a difference when the data blocks are not continuous. And the read routine is somehow opaque: there's no handy info about the status of current page. So a simplified call scheme is employed: to call into readahead whenever the current page falls out of readahead windows. Signed-off-by: Fengguang Wu <wfg@mail.ustc.edu.cn> Cc: Steven Pratt <slpratt@austin.ibm.com> Cc: Ram Pai <linuxram@us.ibm.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/ext4')
-rw-r--r--fs/ext4/dir.c14
1 files changed, 8 insertions, 6 deletions
diff --git a/fs/ext4/dir.c b/fs/ext4/dir.c
index e8ad06e2831..0a872a09fed 100644
--- a/fs/ext4/dir.c
+++ b/fs/ext4/dir.c
@@ -135,12 +135,14 @@ static int ext4_readdir(struct file * filp,
map_bh.b_state = 0;
err = ext4_get_blocks_wrap(NULL, inode, blk, 1, &map_bh, 0, 0);
if (err > 0) {
- page_cache_readahead(sb->s_bdev->bd_inode->i_mapping,
- &filp->f_ra,
- filp,
- map_bh.b_blocknr >>
- (PAGE_CACHE_SHIFT - inode->i_blkbits),
- 1);
+ pgoff_t index = map_bh.b_blocknr >>
+ (PAGE_CACHE_SHIFT - inode->i_blkbits);
+ if (!ra_has_index(&filp->f_ra, index))
+ page_cache_readahead_ondemand(
+ sb->s_bdev->bd_inode->i_mapping,
+ &filp->f_ra, filp,
+ NULL, index, 1);
+ filp->f_ra.prev_index = index;
bh = ext4_bread(NULL, inode, blk, 0, &err);
}