From: Jan Kara <jack@suse.cz>
To: linux-fsdevel@vger.kernel.org
Cc: LKML <linux-kernel@vger.kernel.org>,
Al Viro <viro@ZenIV.linux.org.uk>,
Christoph Hellwig <hch@infradead.org>,
dchinner@redhat.com, Wu Fengguang <fengguang.wu@intel.com>,
Jan Kara <jack@suse.cz>
Subject: [PATCH 7/9] vfs: Move waiting for inode writeback from end_writeback() to evict_inode()
Date: Thu, 3 May 2012 14:48:01 +0200 [thread overview]
Message-ID: <1336049283-5859-8-git-send-email-jack@suse.cz> (raw)
In-Reply-To: <1336049283-5859-1-git-send-email-jack@suse.cz>
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>
---
fs/inode.c | 3 ++-
1 files changed, 2 insertions(+), 1 deletions(-)
diff --git a/fs/inode.c b/fs/inode.c
index 9f4f5fe..501fc5d 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 {
--
1.7.1
next prev parent reply other threads:[~2012-05-03 12:50 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-03 12:47 [PATCH 0/7 v3] writeback: Avoid iput() from flusher thread Jan Kara
2012-05-03 12:47 ` [PATCH 1/9] writeback: Move clearing of I_SYNC into inode_sync_complete() Jan Kara
2012-05-03 12:47 ` [PATCH 2/9] writeback: Move requeueing when I_SYNC set to writeback_sb_inodes() Jan Kara
2012-05-03 12:47 ` [PATCH 3/9] writeback: Move I_DIRTY_PAGES handling Jan Kara
2012-05-03 12:47 ` [PATCH 4/9] writeback: Separate inode requeueing after writeback Jan Kara
2012-05-03 12:47 ` [PATCH 5/9] writeback: Remove wb->list_lock from writeback_single_inode() Jan Kara
2012-05-03 12:48 ` [PATCH 6/9] writeback: Refactor writeback_single_inode() Jan Kara
2012-05-03 12:48 ` Jan Kara [this message]
2012-05-03 12:48 ` [PATCH 8/9] vfs: Rename end_writeback() to clear_inode() Jan Kara
2012-05-03 12:48 ` [PATCH 9/9] writeback: Avoid iput() from flusher thread Jan Kara
2012-05-07 2:57 ` [PATCH 0/7 v3] " Fengguang Wu
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