From 47376ceba54600cec4dd9e7c4fe8b98e4269633a Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Wed, 16 Dec 2009 23:25:50 +0100 Subject: [PATCH] reiserfs: Fix reiserfs lock <-> inode mutex dependency inversion The reiserfs lock -> inode mutex dependency gets inverted when we relax the lock while walking to the tree. To fix this, use a specialized version of reiserfs_mutex_lock_safe that takes care of mutex subclasses. Then we can grab the inode mutex with I_MUTEX_XATTR subclass without any reiserfs lock dependency. This fixes the following report: [ INFO: possible circular locking dependency detected ] 2.6.32-06793-gf405425-dirty #2 ------------------------------------------------------- mv/18566 is trying to acquire lock: (&REISERFS_SB(s)->lock){+.+.+.}, at: [] reiserfs_write_lock+0x28= /0x40 but task is already holding lock: (&sb->s_type->i_mutex_key#5/3){+.+.+.}, at: [] reiserfs_for_each_xattr+0x10c/0x380 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&sb->s_type->i_mutex_key#5/3){+.+.+.}: [] validate_chain+0xa23/0xf70 [] __lock_acquire+0x4e5/0xa70 [] lock_acquire+0x7a/0xa0 [] mutex_lock_nested+0x5f/0x2b0 [] reiserfs_for_each_xattr+0x84/0x380 [] reiserfs_delete_xattrs+0x15/0x50 [] reiserfs_delete_inode+0x8f/0x140 [] generic_delete_inode+0x9c/0x150 [] generic_drop_inode+0x3d/0x60 [] iput+0x47/0x50 [] do_unlinkat+0xdb/0x160 [] sys_unlink+0x10/0x20 [] sysenter_do_call+0x12/0x36 -> #0 (&REISERFS_SB(s)->lock){+.+.+.}: [] validate_chain+0xf68/0xf70 [] __lock_acquire+0x4e5/0xa70 [] lock_acquire+0x7a/0xa0 [] mutex_lock_nested+0x5f/0x2b0 [] reiserfs_write_lock+0x28/0x40 [] search_by_key+0x1f7b/0x21b0 [] search_by_entry_key+0x1f/0x3b0 [] reiserfs_find_entry+0x77/0x400 [] reiserfs_lookup+0x85/0x130 [] __lookup_hash+0xb4/0x110 [] lookup_one_len+0xb3/0x100 [] reiserfs_for_each_xattr+0x120/0x380 [] reiserfs_delete_xattrs+0x15/0x50 [] reiserfs_delete_inode+0x8f/0x140 [] generic_delete_inode+0x9c/0x150 [] generic_drop_inode+0x3d/0x60 [] iput+0x47/0x50 [] dentry_iput+0x6f/0xf0 [] d_kill+0x24/0x50 [] dput+0x5b/0x120 [] sys_renameat+0x1b9/0x230 [] sys_rename+0x28/0x30 [] sysenter_do_call+0x12/0x36 other info that might help us debug this: 2 locks held by mv/18566: #0: (&sb->s_type->i_mutex_key#5/1){+.+.+.}, at: [] lock_rename+0xcc/0xd0 #1: (&sb->s_type->i_mutex_key#5/3){+.+.+.}, at: [] reiserfs_for_each_xattr+0x10c/0x380 stack backtrace: Pid: 18566, comm: mv Tainted: G C 2.6.32-06793-gf405425-dirty #2 Call Trace: [] ? printk+0x18/0x1e [] print_circular_bug+0xc0/0xd0 [] validate_chain+0xf68/0xf70 [] ? trace_hardirqs_off+0xb/0x10 [] __lock_acquire+0x4e5/0xa70 [] lock_acquire+0x7a/0xa0 [] ? reiserfs_write_lock+0x28/0x40 [] mutex_lock_nested+0x5f/0x2b0 [] ? reiserfs_write_lock+0x28/0x40 [] ? reiserfs_write_lock+0x28/0x40 [] ? schedule+0x27a/0x440 [] reiserfs_write_lock+0x28/0x40 [] search_by_key+0x1f7b/0x21b0 [] ? __lock_acquire+0x506/0xa70 [] ? lock_release_non_nested+0x1e7/0x340 [] ? reiserfs_write_lock+0x28/0x40 [] ? trace_hardirqs_on_caller+0x124/0x170 [] ? trace_hardirqs_on+0xb/0x10 [] ? T.316+0x15/0x1a0 [] ? sched_clock_cpu+0x9d/0x100 [] search_by_entry_key+0x1f/0x3b0 [] ? __mutex_unlock_slowpath+0x9a/0x120 [] ? trace_hardirqs_on_caller+0x124/0x170 [] reiserfs_find_entry+0x77/0x400 [] reiserfs_lookup+0x85/0x130 [] ? sched_clock_cpu+0x9d/0x100 [] __lookup_hash+0xb4/0x110 [] lookup_one_len+0xb3/0x100 [] reiserfs_for_each_xattr+0x120/0x380 [] ? delete_one_xattr+0x0/0x1c0 [] ? math_error+0x22/0x150 [] ? reiserfs_write_lock+0x28/0x40 [] reiserfs_delete_xattrs+0x15/0x50 [] ? reiserfs_write_lock+0x28/0x40 [] reiserfs_delete_inode+0x8f/0x140 [] ? generic_delete_inode+0x5f/0x150 [] ? reiserfs_delete_inode+0x0/0x140 [] generic_delete_inode+0x9c/0x150 [] generic_drop_inode+0x3d/0x60 [] iput+0x47/0x50 [] dentry_iput+0x6f/0xf0 [] d_kill+0x24/0x50 [] dput+0x5b/0x120 [] sys_renameat+0x1b9/0x230 [] ? sched_clock_cpu+0x9d/0x100 [] ? trace_hardirqs_off+0xb/0x10 [] ? cpu_clock+0x4e/0x60 [] ? do_page_fault+0x155/0x370 [] ? up_read+0x16/0x30 [] ? do_page_fault+0x155/0x370 [] sys_rename+0x28/0x30 [] sysenter_do_call+0x12/0x36 Reported-by: Alexander Beregalov Signed-off-by: Frederic Weisbecker Cc: Chris Mason Cc: Ingo Molnar Cc: Thomas Gleixner --- fs/reiserfs/xattr.c | 3 ++- include/linux/reiserfs_fs.h | 9 +++++++++ 2 files changed, 11 insertions(+), 1 deletion(-) diff --git a/fs/reiserfs/xattr.c b/fs/reiserfs/xattr.c index 58aa8e75f7f5..8891cd88a3f4 100644 --- a/fs/reiserfs/xattr.c +++ b/fs/reiserfs/xattr.c @@ -243,7 +243,8 @@ static int reiserfs_for_each_xattr(struct inode *inode, goto out_dir; } - mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_XATTR); + reiserfs_mutex_lock_nested_safe(&dir->d_inode->i_mutex, I_MUTEX_XATTR, + inode->i_sb); buf.xadir = dir; err = reiserfs_readdir_dentry(dir, &buf, fill_with_dentries, &pos); while ((err == 0 || err == -ENOSPC) && buf.count) { diff --git a/include/linux/reiserfs_fs.h b/include/linux/reiserfs_fs.h index a05b4a20768d..4351b49e2b1e 100644 --- a/include/linux/reiserfs_fs.h +++ b/include/linux/reiserfs_fs.h @@ -97,6 +97,15 @@ static inline void reiserfs_mutex_lock_safe(struct mutex *m, reiserfs_write_lock(s); } +static inline void +reiserfs_mutex_lock_nested_safe(struct mutex *m, unsigned int subclass, + struct super_block *s) +{ + reiserfs_write_unlock(s); + mutex_lock_nested(m, subclass); + reiserfs_write_lock(s); +} + /* * When we schedule, we usually want to also release the write lock, * according to the previous bkl based locking scheme of reiserfs. -- 2.30.2