From 4195f73d1329e49727bcceb028e58cb38376c2b0 Mon Sep 17 00:00:00 2001 From: Nick Piggin Date: Thu, 28 May 2009 09:01:15 +0200 Subject: [PATCH] fs: block_dump missing dentry locking I think the block_dump output in __mark_inode_dirty is missing dentry locking. Surely the i_dentry list can change any time, so we may not even *get* a dentry there. If we do get one by chance, then it would appear to be able to go away or get renamed at any time... Signed-off-by: Al Viro --- fs/fs-writeback.c | 41 ++++++++++++++++++++++++----------------- 1 file changed, 24 insertions(+), 17 deletions(-) diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index efcedb6d9cbc..40308e98c6a4 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -64,6 +64,28 @@ static void writeback_release(struct backing_dev_info *bdi) clear_bit(BDI_pdflush, &bdi->state); } +static noinline void block_dump___mark_inode_dirty(struct inode *inode) +{ + if (inode->i_ino || strcmp(inode->i_sb->s_id, "bdev")) { + struct dentry *dentry; + const char *name = "?"; + + dentry = d_find_alias(inode); + if (dentry) { + spin_lock(&dentry->d_lock); + name = (const char *) dentry->d_name.name; + } + printk(KERN_DEBUG + "%s(%d): dirtied inode %lu (%s) on %s\n", + current->comm, task_pid_nr(current), inode->i_ino, + name, inode->i_sb->s_id); + if (dentry) { + spin_unlock(&dentry->d_lock); + dput(dentry); + } + } +} + /** * __mark_inode_dirty - internal function * @inode: inode to mark @@ -114,23 +136,8 @@ void __mark_inode_dirty(struct inode *inode, int flags) if ((inode->i_state & flags) == flags) return; - if (unlikely(block_dump)) { - struct dentry *dentry = NULL; - const char *name = "?"; - - if (!list_empty(&inode->i_dentry)) { - dentry = list_entry(inode->i_dentry.next, - struct dentry, d_alias); - if (dentry && dentry->d_name.name) - name = (const char *) dentry->d_name.name; - } - - if (inode->i_ino || strcmp(inode->i_sb->s_id, "bdev")) - printk(KERN_DEBUG - "%s(%d): dirtied inode %lu (%s) on %s\n", - current->comm, task_pid_nr(current), inode->i_ino, - name, inode->i_sb->s_id); - } + if (unlikely(block_dump)) + block_dump___mark_inode_dirty(inode); spin_lock(&inode_lock); if ((inode->i_state & flags) != flags) {