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authorJan Kara <jack@suse.cz>2012-05-03 14:48:01 +0200
committerFengguang Wu <fengguang.wu@intel.com>2012-05-06 13:43:40 +0800
commit7994e6f7254354e03028a11f98a27bd67dace9f1 (patch)
treeb93db15bf5e4cd890670db0fd36575b5efce2366
parent4f8ad655dbc82cf05d2edc11e66b78a42d38bf93 (diff)
vfs: Move waiting for inode writeback from end_writeback() to evict_inode()
Currently, I_SYNC can never be set when evict_inode() (and thus end_writeback()) is called because flusher thread holds inode reference while inode is under writeback. As a result inode_sync_wait() in those places currently does nothing. However that is going to change and unveils problems with calling inode_sync_wait() from end_writeback(). Several filesystems call end_writeback() after they have deleted the inode (btrfs, gfs2, ...) and other filesystems (ext3, ext4, reiserfs, ...) can deadlock when waiting for I_SYNC because they call end_writeback() from within a transaction. To avoid these issues, we move inode_sync_wait() into evict_inode() before calling ->evict_inode(). That way we preserve the current property that ->evict_inode() and writeback never run in parallel and all filesystems are safe. Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
-rw-r--r--fs/inode.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/fs/inode.c b/fs/inode.c
index 9f4f5fecc096..501fc5daf6f4 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -500,7 +500,6 @@ void end_writeback(struct inode *inode)
BUG_ON(!list_empty(&inode->i_data.private_list));
BUG_ON(!(inode->i_state & I_FREEING));
BUG_ON(inode->i_state & I_CLEAR);
- inode_sync_wait(inode);
/* don't need i_lock here, no concurrent mods to i_state */
inode->i_state = I_FREEING | I_CLEAR;
}
@@ -531,6 +530,8 @@ static void evict(struct inode *inode)
inode_sb_list_del(inode);
+ inode_sync_wait(inode);
+
if (op->evict_inode) {
op->evict_inode(inode);
} else {