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| author | Jiaying Zhang <jiayingz@google.com> | 2011-08-13 12:17:13 -0400 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2011-08-13 12:17:13 -0400 |
| commit | 2581fdc810889fdea97689cb62481201d579c796 (patch) | |
| tree | 55d7a2244a5efa184e290446c0ee3f61b71bf264 | |
| parent | 441c850857148935babe000fc2ba1455fe54a6a9 (diff) | |
| download | linux-3.10-2581fdc810889fdea97689cb62481201d579c796.tar.gz linux-3.10-2581fdc810889fdea97689cb62481201d579c796.tar.bz2 linux-3.10-2581fdc810889fdea97689cb62481201d579c796.zip | |
ext4: call ext4_ioend_wait and ext4_flush_completed_IO in ext4_evict_inode
Flush inode's i_completed_io_list before calling ext4_io_wait to
prevent the following deadlock scenario: A page fault happens while
some process is writing inode A. During page fault,
shrink_icache_memory is called that in turn evicts another inode
B. Inode B has some pending io_end work so it calls ext4_ioend_wait()
that waits for inode B's i_ioend_count to become zero. However, inode
B's ioend work was queued behind some of inode A's ioend work on the
same cpu's ext4-dio-unwritten workqueue. As the ext4-dio-unwritten
thread on that cpu is processing inode A's ioend work, it tries to
grab inode A's i_mutex lock. Since the i_mutex lock of inode A is
still hold before the page fault happened, we enter a deadlock.
Also moves ext4_flush_completed_IO and ext4_ioend_wait from
ext4_destroy_inode() to ext4_evict_inode(). During inode deleteion,
ext4_evict_inode() is called before ext4_destroy_inode() and in
ext4_evict_inode(), we may call ext4_truncate() without holding
i_mutex lock. As a result, there is a race between flush_completed_IO
that is called from ext4_ext_truncate() and ext4_end_io_work, which
may cause corruption on an io_end structure. This change moves
ext4_flush_completed_IO and ext4_ioend_wait from ext4_destroy_inode()
to ext4_evict_inode() to resolve the race between ext4_truncate() and
ext4_end_io_work during inode deletion.
Signed-off-by: Jiaying Zhang <jiayingz@google.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: stable@kernel.org
| -rw-r--r-- | fs/ext4/inode.c | 6 | ||||
| -rw-r--r-- | fs/ext4/super.c | 1 |
2 files changed, 6 insertions, 1 deletions
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index ad3a7ca2106..7dd69810782 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -120,6 +120,12 @@ void ext4_evict_inode(struct inode *inode) int err; trace_ext4_evict_inode(inode); + + mutex_lock(&inode->i_mutex); + ext4_flush_completed_IO(inode); + mutex_unlock(&inode->i_mutex); + ext4_ioend_wait(inode); + if (inode->i_nlink) { /* * When journalling data dirty buffers are tracked only in the diff --git a/fs/ext4/super.c b/fs/ext4/super.c index 4687fea0c00..44d0c8db223 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -919,7 +919,6 @@ static void ext4_i_callback(struct rcu_head *head) static void ext4_destroy_inode(struct inode *inode) { - ext4_ioend_wait(inode); if (!list_empty(&(EXT4_I(inode)->i_orphan))) { ext4_msg(inode->i_sb, KERN_ERR, "Inode %lu (%p): orphan list check failed!", |