Commit-ID: 7b61cf54a2445ad21df9dd44f0c8bb90154ddea8
Gitweb: http://git.kernel.org/tip/7b61cf54a2445ad21df9dd44f0c8bb90154ddea8
Author: Tao Ma <tao.ma@xxxxxxxxxx>
AuthorDate: Thu, 17 Jun 2010 14:14:36 +0800
Committer: Tao Ma <tao.ma@xxxxxxxxxx>
CommitDate: Thu, 12 Aug 2010 10:40:01 +0800
ocfs2: Add readahead support for CoW.
Add a new function ocfs2_readahead_for_cow so that
we start readahead before we start our CoW.
Signed-off-by: Tao Ma <tao.ma@xxxxxxxxxx>
---
fs/ocfs2/refcounttree.c | 24 ++++++++++++++++++++++++
1 files changed, 24 insertions(+), 0 deletions(-)
diff --git a/fs/ocfs2/refcounttree.c b/fs/ocfs2/refcounttree.c
index 66dab3c..ad08c11 100644
--- a/fs/ocfs2/refcounttree.c
+++ b/fs/ocfs2/refcounttree.c
@@ -3398,6 +3398,28 @@ static int ocfs2_replace_cow(struct ocfs2_cow_context *context)
return ret;
}
+static void ocfs2_readahead_for_cow(struct inode *inode,
+ struct file *file,
+ u32 start, u32 len)
+{
+ struct address_space *mapping;
+ pgoff_t index;
+ unsigned long num_pages;
+ int cs_bits = OCFS2_SB(inode->i_sb)->s_clustersize_bits;
+
+ if (!file)
+ return;
+
+ mapping = file->f_mapping;
+ num_pages = (len << cs_bits) >> PAGE_CACHE_SHIFT;
+ if (!num_pages)
+ num_pages = 1;
+
+ index = ((loff_t)start << cs_bits) >> PAGE_CACHE_SHIFT;
+ page_cache_sync_readahead(mapping, &file->f_ra, file,
+ index, num_pages);
+}
+
/*
* Starting at cpos, try to CoW write_len clusters. Don't CoW
* past max_cpos. This will stop when it runs into a hole or an
@@ -3433,6 +3455,8 @@ static int ocfs2_refcount_cow_hunk(struct inode *inode,
BUG_ON(cow_len == 0);
+ ocfs2_readahead_for_cow(inode, file, cow_start, cow_len);
+
context = kzalloc(sizeof(struct ocfs2_cow_context), GFP_NOFS);
if (!context) {
ret = -ENOMEM;
--
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