[PATCH] autofs4: tree race fix
For tree mount maps, a call to chdir or chroot, to a directory above the
moint point directories at a certain time during the expire results in the
expire incorrectly thinking the tree is not busy. This patch adds a check
to see if the filesystem above the tree mount points is busy and also locks
the filesystem during the tree mount expire to prevent the race.
Signed-off-by: Ian Kent <raven@themaw.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/fs/autofs4/autofs_i.h b/fs/autofs4/autofs_i.h
index 9789877..c7b2b88 100644
--- a/fs/autofs4/autofs_i.h
+++ b/fs/autofs4/autofs_i.h
@@ -102,6 +102,7 @@
int needs_reghost;
struct super_block *sb;
struct semaphore wq_sem;
+ spinlock_t fs_lock;
struct autofs_wait_queue *queues; /* Wait queue pointer */
};
@@ -127,9 +128,18 @@
static inline int autofs4_ispending(struct dentry *dentry)
{
struct autofs_info *inf = autofs4_dentry_ino(dentry);
+ int pending = 0;
- return (dentry->d_flags & DCACHE_AUTOFS_PENDING) ||
- (inf != NULL && inf->flags & AUTOFS_INF_EXPIRING);
+ if (dentry->d_flags & DCACHE_AUTOFS_PENDING)
+ return 1;
+
+ if (inf) {
+ spin_lock(&inf->sbi->fs_lock);
+ pending = inf->flags & AUTOFS_INF_EXPIRING;
+ spin_unlock(&inf->sbi->fs_lock);
+ }
+
+ return pending;
}
static inline void autofs4_copy_atime(struct file *src, struct file *dst)