On Sun, 2012-04-15 at 14:05 -0700, Jan Sanislo wrote:
> We are seeing occasional (approx. weekly) automount/kernel crashes using
> kernel version 3.1.7 and autofs version 5.0.5-39. The log files show
> the following traceback:
Could you give this patch a try please.
autofs4 - fix get_next_positive_subdir()
From: Ian Kent <ikent@xxxxxxxxxx>
The function get_next_positive_subdir() was not using the correct
d_subdirs list locking.
Signed-off-by: Ian Kent <ikent@xxxxxxxxxx>
---
fs/autofs4/expire.c | 15 +++++++--------
1 files changed, 7 insertions(+), 8 deletions(-)
diff --git a/fs/autofs4/expire.c b/fs/autofs4/expire.c
index 450f529..bc87da4 100644
--- a/fs/autofs4/expire.c
+++ b/fs/autofs4/expire.c
@@ -97,9 +97,9 @@ static struct dentry *get_next_positive_subdir(struct dentry *prev,
struct dentry *p, *q;
spin_lock(&sbi->lookup_lock);
+ spin_lock(&root->d_lock);
if (prev == NULL) {
- spin_lock(&root->d_lock);
prev = dget_dlock(root);
next = prev->d_subdirs.next;
p = prev;
@@ -107,12 +107,11 @@ static struct dentry *get_next_positive_subdir(struct dentry *prev,
}
p = prev;
- spin_lock(&p->d_lock);
-again:
+next:
next = p->d_u.d_child.next;
start:
if (next == &root->d_subdirs) {
- spin_unlock(&p->d_lock);
+ spin_unlock(&root->d_lock);
spin_unlock(&sbi->lookup_lock);
dput(prev);
return NULL;
@@ -122,14 +121,14 @@ start:
spin_lock_nested(&q->d_lock, DENTRY_D_LOCK_NESTED);
/* Negative dentry - try next */
- if (!simple_positive(q)) {
- spin_unlock(&p->d_lock);
+ if (q->d_count == 0 || !simple_positive(q)) {
+ spin_unlock(&q->d_lock);
p = q;
- goto again;
+ goto next;
}
dget_dlock(q);
spin_unlock(&q->d_lock);
- spin_unlock(&p->d_lock);
+ spin_unlock(&root->d_lock);
spin_unlock(&sbi->lookup_lock);
dput(prev);
--
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