linux-kernel - [GFS2] Put back semaphore to avoid umount proble

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <1170686824.11001.371.camel@quoit.chygwyn.com>
Date:	Mon, 05 Feb 2007 14:47:04 +0000
From:	Steven Whitehouse <swhiteho@...hat.com>
To:	linux-kernel@...r.kernel.org
Cc:	David Teigland <teigland@...hat.com>, cluster-devel@...hat.com
Subject: [GFS2] Put back semaphore to avoid umount proble

>>From eeca71338ea3b4b3bcd829b998b35c015316b134 Mon Sep 17 00:00:00 2001
From: Steven Whitehouse <swhiteho@...hat.com>
Date: Mon, 29 Jan 2007 11:51:45 +0000
Subject: [PATCH] [GFS2] Put back semaphore to avoid umount problem

Dave Teigland fixed this bug a while back, but I managed to mistakenly
remove the semaphore during later development. It is required to avoid
the list of inodes changing during an invalidate_inodes call. I have
made it an rwsem since the read side will be taken frequently during
normal filesystem operation. The write site will only happen during
umount of the file system.

Also the bug only triggers when using the DLM lock manager and only then
under certain conditions as its timing related.

Signed-off-by: Steven Whitehouse <swhiteho@...hat.com>
Cc: David Teigland <teigland@...hat.com>

diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
index c070ede..6618c11 100644
--- a/fs/gfs2/glock.c
+++ b/fs/gfs2/glock.c
@@ -20,6 +20,7 @@
 #include <linux/list.h>
 #include <linux/lm_interface.h>
 #include <linux/wait.h>
+#include <linux/rwsem.h>
 #include <asm/uaccess.h>
 
 #include "gfs2.h"
@@ -45,6 +46,7 @@ static int dump_glock(struct gfs2_glock *gl);
 static int dump_inode(struct gfs2_inode *ip);
 static void gfs2_glock_xmote_th(struct gfs2_holder *gh);
 static void gfs2_glock_drop_th(struct gfs2_glock *gl);
+static DECLARE_RWSEM(gfs2_umount_flush_sem);
 
 #define GFS2_GL_HASH_SHIFT      15
 #define GFS2_GL_HASH_SIZE       (1 << GFS2_GL_HASH_SHIFT)
@@ -1578,12 +1580,14 @@ void gfs2_glock_cb(void *cb_data, unsigned int type, void *data)
 		struct lm_async_cb *async = data;
 		struct gfs2_glock *gl;
 
+		down_read(&gfs2_umount_flush_sem);
 		gl = gfs2_glock_find(sdp, &async->lc_name);
 		if (gfs2_assert_warn(sdp, gl))
 			return;
 		if (!gfs2_assert_warn(sdp, gl->gl_req_bh))
 			gl->gl_req_bh(gl, async->lc_ret);
 		gfs2_glock_put(gl);
+		up_read(&gfs2_umount_flush_sem);
 		return;
 	}
 
@@ -1828,7 +1832,9 @@ void gfs2_gl_hash_clear(struct gfs2_sbd *sdp, int wait)
 			t = jiffies;
 		}
 
+		down_write(&gfs2_umount_flush_sem);
 		invalidate_inodes(sdp->sd_vfs);
+		up_write(&gfs2_umount_flush_sem);
 		msleep(10);
 	}
 }
-- 
1.4.4.2



-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/