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autofs4 - fix get_next_positive_dentry()

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The initialization condition in fs/autofs4/expire.c:get_next_positive_dentry()
appears to be incorrect. If prev == NULL I believe that root should be
returned.

Further down, at the current dentry check for it being simple_positive()
it looks like the d_lock for dentry p should be dropped instead of dentry
ret, otherwise when p is assinged to ret we end up with no lock on p and
a lost lock on ret, which leads to a deadlock.

Signed-off-by: Ian Kent <raven@themaw.net>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Ian Kent
2011-01-18 12:06:04 +08:00
committed by Al Viro
parent 6845a44a31
commit c14cc63a63
1 changed files with 2 additions and 2 deletions
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4
fs/autofs4/expire.c
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@@ -96,7 +96,7 @@ static struct dentry *get_next_positive_dentry(struct dentry *prev,
struct dentry *p, *ret; struct dentry *p, *ret;
if (prev == NULL) if (prev == NULL)
return dget(prev); return dget(root);
spin_lock(&autofs4_lock); spin_lock(&autofs4_lock);
relock: relock:
@@ -133,7 +133,7 @@ again:
spin_lock_nested(&ret->d_lock, DENTRY_D_LOCK_NESTED); spin_lock_nested(&ret->d_lock, DENTRY_D_LOCK_NESTED);
/* Negative dentry - try next */ /* Negative dentry - try next */
if (!simple_positive(ret)) { if (!simple_positive(ret)) {
spin_unlock(&ret->d_lock); spin_unlock(&p->d_lock);
p = ret; p = ret;
goto again; goto again;
} }