>From 2ca99501fa5422e84f18333918a503433449e2b5 Mon Sep 17 00:00:00 2001
From: Steven Whitehouse <[EMAIL PROTECTED]>
Date: Wed, 8 Nov 2006 10:26:54 -0500
Subject: [PATCH] [GFS2] Fix page lock/glock deadlock
This fixes a race between the glock and the page lock encountered
during truncate in gfs2_readpage and gfs2_prepare_write. The gfs2_readpages
function doesn't need the same fix since it only uses a try lock anyway, so
it will fail back to gfs2_readpage in the case of a potential deadlock.
This bug was spotted by Russell Cattelan.
Cc: Russell Cattelan <[EMAIL PROTECTED]>
Signed-off-by: Steven Whitehouse <[EMAIL PROTECTED]>
---
fs/gfs2/glock.h | 1 -
fs/gfs2/ops_address.c | 13 +++++++++----
2 files changed, 9 insertions(+), 5 deletions(-)
diff --git a/fs/gfs2/glock.h b/fs/gfs2/glock.h
index b985627..a331bf8 100644
--- a/fs/gfs2/glock.h
+++ b/fs/gfs2/glock.h
@@ -27,7 +27,6 @@ #define GL_SKIP 0x00000100
#define GL_ATIME 0x00000200
#define GL_NOCACHE 0x00000400
#define GL_NOCANCEL 0x00001000
-#define GL_AOP 0x00004000
#define GLR_TRYFAILED 13
#define GLR_CANCELED 14
diff --git a/fs/gfs2/ops_address.c b/fs/gfs2/ops_address.c
index 5c3962c..3822189 100644
--- a/fs/gfs2/ops_address.c
+++ b/fs/gfs2/ops_address.c
@@ -230,7 +230,7 @@ static int gfs2_readpage(struct file *fi
/* gfs2_sharewrite_nopage has grabbed the
ip->i_gl already */
goto skip_lock;
}
- gfs2_holder_init(ip->i_gl, LM_ST_SHARED, GL_ATIME|GL_AOP, &gh);
+ gfs2_holder_init(ip->i_gl, LM_ST_SHARED,
GL_ATIME|LM_FLAG_TRY_1CB, &gh);
do_unlock = 1;
error = gfs2_glock_nq_m_atime(1, &gh);
if (unlikely(error))
@@ -254,6 +254,8 @@ skip_lock:
out:
return error;
out_unlock:
+ if (error == GLR_TRYFAILED)
+ error = AOP_TRUNCATED_PAGE;
unlock_page(page);
if (do_unlock)
gfs2_holder_uninit(&gh);
@@ -293,7 +295,7 @@ static int gfs2_readpages(struct file *f
goto skip_lock;
}
gfs2_holder_init(ip->i_gl, LM_ST_SHARED,
- LM_FLAG_TRY_1CB|GL_ATIME|GL_AOP, &gh);
+ LM_FLAG_TRY_1CB|GL_ATIME, &gh);
do_unlock = 1;
ret = gfs2_glock_nq_m_atime(1, &gh);
if (ret == GLR_TRYFAILED)
@@ -366,10 +368,13 @@ static int gfs2_prepare_write(struct fil
unsigned int write_len = to - from;
- gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, GL_ATIME|GL_AOP, &ip->i_gh);
+ gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, GL_ATIME|LM_FLAG_TRY_1CB,
&ip->i_gh);
error = gfs2_glock_nq_m_atime(1, &ip->i_gh);
- if (error)
+ if (unlikely(error)) {
+ if (error == GLR_TRYFAILED)
+ error = AOP_TRUNCATED_PAGE;
goto out_uninit;
+ }
gfs2_write_calc_reserv(ip, write_len, &data_blocks, &ind_blocks);
--
1.4.1
-
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