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Linux: osi_TryEvictVCache: Don’t skip the first dentry if D_ALIAS_IS_HLIST

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An hlist doesn’t begin with a sentinel like a list does, so the old
code would skip the first dentry or crash with a NULL dereference if
there wasn’t one.  Use the kernel’s list_for_each_entry or
hlist_for_each_entry macros instead of trying to do it manually.

Should fix a crash observed by Alex Chernyakhovsky on kernel 3.6 and
newer.

Change-Id: I6d7bd190013a0250ca896af8d5182df55a3376b0
Signed-off-by: Anders Kaseorg <andersk@mit.edu>
Reviewed-on: http://gerrit.openafs.org/9857
Reviewed-by: Alex Chernyakhovsky <achernya@mit.edu>
Tested-by: Alex Chernyakhovsky <achernya@mit.edu>
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Marc Dionne <marc.c.dionne@gmail.com>
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>
This commit is contained in:
Anders Kaseorg 2013-05-07 00:27:33 -04:00 committed by Jeffrey Altman
parent 13a3ba7ba2
commit ad6e31d5fe
1 changed files with 9 additions and 21 deletions
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30
src/afs/LINUX/osi_vcache.c
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@ -19,10 +19,8 @@ osi_TryEvictVCache(struct vcache *avc, int *slept, int defersleep) {
struct dentry *dentry;
struct inode *inode = AFSTOV(avc);
#if defined(D_ALIAS_IS_HLIST)
struct hlist_node *cur, *head, *list_end;
#else
struct list_head *cur, *head, *list_end;
#if defined(D_ALIAS_IS_HLIST) && !defined(HLIST_ITERATOR_NO_NODE)
struct hlist_node *p;
#endif
/* First, see if we can evict the inode from the dcache */
@ -33,13 +31,9 @@ osi_TryEvictVCache(struct vcache *avc, int *slept, int defersleep) {
#if defined(HAVE_DCACHE_LOCK)
spin_lock(&dcache_lock);
head = &inode->i_dentry;
restart:
cur = head;
while ((cur = cur->next) != head) {
dentry = list_entry(cur, struct dentry, d_alias);
list_for_each_entry(dentry, &inode->i_dentry, d_alias) {
if (d_unhashed(dentry))
continue;
dget_locked(dentry);
@ -57,23 +51,17 @@ restart:
spin_unlock(&dcache_lock);
#else /* HAVE_DCACHE_LOCK */
spin_lock(&inode->i_lock);
#if defined(D_ALIAS_IS_HLIST)
head = inode->i_dentry.first;
list_end = NULL;
#else
head = &inode->i_dentry;
list_end = head;
#endif
restart:
cur = head;
while ((cur = cur->next) != list_end) {
#if defined(D_ALIAS_IS_HLIST)
dentry = hlist_entry(cur, struct dentry, d_alias);
# if defined(HLIST_ITERATOR_NO_NODE)
hlist_for_each_entry(dentry, &inode->i_dentry, d_alias) {
# else
hlist_for_each_entry(dentry, p, &inode->i_dentry, d_alias) {
# endif
#else
dentry = list_entry(cur, struct dentry, d_alias);
list_for_each_entry(dentry, &inode->i_dentry, d_alias) {
#endif
spin_lock(&dentry->d_lock);
if (d_unhashed(dentry)) {
spin_unlock(&dentry->d_lock);