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...
I've just gone the very-safe route and used the dcache helper to find this,
and done the full refcounting/locking thing. Also just moved it to its
own function to reduce clutter a bit.
Is my thinking correct?
Thanks,
Nick
---
fs/fs-writeback.c | 41 ++++++++++++++++++++++++-----------------
1 file changed, 24 insertions(+), 17 deletions(-)
Index: linux-2.6/fs/fs-writeback.c
===================================================================
--- linux-2.6.orig/fs/fs-writeback.c
+++ linux-2.6/fs/fs-writeback.c
@@ -64,6 +64,28 @@ static void writeback_release(struct bac
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 *in
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) {
--
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