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authorWu Fengguang <fengguang.wu@intel.com>2009-04-02 16:56:34 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2009-04-02 19:04:48 -0700
commitb6fac63cc1f52ec27f29fe6c6c8494a2ffac33fd (patch)
tree78b4da8231fb80ea05fffc65c4647957b5a858fb /fs
parent33e5d76979cf01e3834814fe0aea569d1d602c1a (diff)
downloadlinux-b6fac63cc1f52ec27f29fe6c6c8494a2ffac33fd.tar.gz
vfs: skip I_CLEAR state inodes
clear_inode() will switch inode state from I_FREEING to I_CLEAR, and do so _outside_ of inode_lock. So any I_FREEING testing is incomplete without a coupled testing of I_CLEAR. So add I_CLEAR tests to drop_pagecache_sb(), generic_sync_sb_inodes() and add_dquot_ref(). Masayoshi MIZUMA discovered the bug in drop_pagecache_sb() and Jan Kara reminds fixing the other two cases. Masayoshi MIZUMA has a nice panic flow: ===================================================================== [process A] | [process B] | | | prune_icache() | drop_pagecache() | spin_lock(&inode_lock) | drop_pagecache_sb() | inode->i_state |= I_FREEING; | | | spin_unlock(&inode_lock) | V | | | spin_lock(&inode_lock) | V | | | dispose_list() | | | list_del() | | | clear_inode() | | | inode->i_state = I_CLEAR | | | | | V | | | if (inode->i_state & (I_FREEING|I_WILL_FREE)) | | | continue; <==== NOT MATCH | | | | | | (DANGER from here on! Accessing disposing inode!) | | | | | | __iget() | | | list_move() <===== PANIC on poisoned list !! V V | (time) ===================================================================== Reported-by: Masayoshi MIZUMA <m.mizuma@jp.fujitsu.com> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs')
-rw-r--r--fs/drop_caches.c2
-rw-r--r--fs/fs-writeback.c3
-rw-r--r--fs/quota/dquot.c2
3 files changed, 4 insertions, 3 deletions
diff --git a/fs/drop_caches.c b/fs/drop_caches.c
index 44d725f612c..b6a719a909f 100644
--- a/fs/drop_caches.c
+++ b/fs/drop_caches.c
@@ -18,7 +18,7 @@ static void drop_pagecache_sb(struct super_block *sb)
spin_lock(&inode_lock);
list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
- if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW))
+ if (inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE|I_NEW))
continue;
if (inode->i_mapping->nrpages == 0)
continue;
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index e3fe9918faa..f81f9e71871 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -538,7 +538,8 @@ void generic_sync_sb_inodes(struct super_block *sb,
list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
struct address_space *mapping;
- if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW))
+ if (inode->i_state &
+ (I_FREEING|I_CLEAR|I_WILL_FREE|I_NEW))
continue;
mapping = inode->i_mapping;
if (mapping->nrpages == 0)
diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c
index 2ca967a5ef7..607c579e5ec 100644
--- a/fs/quota/dquot.c
+++ b/fs/quota/dquot.c
@@ -823,7 +823,7 @@ static void add_dquot_ref(struct super_block *sb, int type)
spin_lock(&inode_lock);
list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
- if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW))
+ if (inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE|I_NEW))
continue;
if (!atomic_read(&inode->i_writecount))
continue;