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| author | Wu Fengguang <fengguang.wu@intel.com> | 2009-04-02 16:56:34 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-04-02 19:04:48 -0700 |
| commit | b6fac63cc1f52ec27f29fe6c6c8494a2ffac33fd (patch) | |
| tree | 78b4da8231fb80ea05fffc65c4647957b5a858fb /fs/drop_caches.c | |
| parent | 33e5d76979cf01e3834814fe0aea569d1d602c1a (diff) | |
| download | linux-exynos-b6fac63cc1f52ec27f29fe6c6c8494a2ffac33fd.tar.gz linux-exynos-b6fac63cc1f52ec27f29fe6c6c8494a2ffac33fd.tar.bz2 linux-exynos-b6fac63cc1f52ec27f29fe6c6c8494a2ffac33fd.zip | |
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/drop_caches.c')
| -rw-r--r-- | fs/drop_caches.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/drop_caches.c b/fs/drop_caches.c index 44d725f612cf..b6a719a909f8 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; |