From e9dfc0b2bc42761410e8db6c252c6c5889e178b8 Mon Sep 17 00:00:00 2001
From: Mark Fasheh <mark.fasheh@oracle.com>
Date: Mon, 14 May 2007 11:38:51 -0700
Subject: [PATCH] ocfs2: trylock in ocfs2_readpage()
Similarly to the page lock / cluster lock inversion in ocfs2_readpage, we
can deadlock on ip_alloc_sem. We can down_read_trylock() instead and just
return AOP_TRUNCATED_PAGE if the operation fails.
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
---
fs/ocfs2/aops.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c
index 8e7cafb5fc6c..30306707b2ca 100644
--- a/fs/ocfs2/aops.c
+++ b/fs/ocfs2/aops.c
@@ -222,7 +222,10 @@ static int ocfs2_readpage(struct file *file, struct page *page)
goto out;
}
- down_read(&OCFS2_I(inode)->ip_alloc_sem);
+ if (down_read_trylock(&OCFS2_I(inode)->ip_alloc_sem) == 0) {
+ ret = AOP_TRUNCATED_PAGE;
+ goto out_meta_unlock;
+ }
/*
* i_size might have just been updated as we grabed the meta lock. We
@@ -258,6 +261,7 @@ static int ocfs2_readpage(struct file *file, struct page *page)
ocfs2_data_unlock(inode, 0);
out_alloc:
up_read(&OCFS2_I(inode)->ip_alloc_sem);
+out_meta_unlock:
ocfs2_meta_unlock(inode, 0);
out:
if (unlock)
--
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