diff options
| -rw-r--r-- | fs/autofs4/autofs_i.h | 4 | ||||
| -rw-r--r-- | fs/autofs4/expire.c | 46 |
2 files changed, 42 insertions, 8 deletions
diff --git a/fs/autofs4/autofs_i.h b/fs/autofs4/autofs_i.h index 2f1032f12d91..8e98cf954bab 100644 --- a/fs/autofs4/autofs_i.h +++ b/fs/autofs4/autofs_i.h @@ -79,6 +79,10 @@ struct autofs_info { }; #define AUTOFS_INF_EXPIRING (1<<0) /* dentry is in the process of expiring */ +#define AUTOFS_INF_NO_RCU (1<<1) /* the dentry is being considered + * for expiry, so RCU_walk is + * not permitted + */ #define AUTOFS_INF_PENDING (1<<2) /* dentry pending mount */ struct autofs_wait_queue { diff --git a/fs/autofs4/expire.c b/fs/autofs4/expire.c index af141fc8cfe6..683a5b9ce22a 100644 --- a/fs/autofs4/expire.c +++ b/fs/autofs4/expire.c @@ -321,10 +321,19 @@ struct dentry *autofs4_expire_direct(struct super_block *sb, if (ino->flags & AUTOFS_INF_PENDING) goto out; if (!autofs4_direct_busy(mnt, root, timeout, do_now)) { - ino->flags |= AUTOFS_INF_EXPIRING; - init_completion(&ino->expire_complete); + ino->flags |= AUTOFS_INF_NO_RCU; spin_unlock(&sbi->fs_lock); - return root; + synchronize_rcu(); + spin_lock(&sbi->fs_lock); + if (!autofs4_direct_busy(mnt, root, timeout, do_now)) { + ino->flags |= AUTOFS_INF_EXPIRING; + smp_mb(); + ino->flags &= ~AUTOFS_INF_NO_RCU; + init_completion(&ino->expire_complete); + spin_unlock(&sbi->fs_lock); + return root; + } + ino->flags &= ~AUTOFS_INF_NO_RCU; } out: spin_unlock(&sbi->fs_lock); @@ -442,12 +451,29 @@ struct dentry *autofs4_expire_indirect(struct super_block *sb, dentry = NULL; while ((dentry = get_next_positive_subdir(dentry, root))) { spin_lock(&sbi->fs_lock); - expired = should_expire(dentry, mnt, timeout, how); - if (expired) { + ino = autofs4_dentry_ino(dentry); + if (ino->flags & AUTOFS_INF_NO_RCU) + expired = NULL; + else + expired = should_expire(dentry, mnt, timeout, how); + if (!expired) { + spin_unlock(&sbi->fs_lock); + continue; + } + ino = autofs4_dentry_ino(expired); + ino->flags |= AUTOFS_INF_NO_RCU; + spin_unlock(&sbi->fs_lock); + synchronize_rcu(); + spin_lock(&sbi->fs_lock); + if (should_expire(expired, mnt, timeout, how)) { if (expired != dentry) dput(dentry); goto found; } + + ino->flags &= ~AUTOFS_INF_NO_RCU; + if (expired != dentry) + dput(expired); spin_unlock(&sbi->fs_lock); } return NULL; @@ -455,8 +481,9 @@ struct dentry *autofs4_expire_indirect(struct super_block *sb, found: DPRINTK("returning %p %.*s", expired, (int)expired->d_name.len, expired->d_name.name); - ino = autofs4_dentry_ino(expired); ino->flags |= AUTOFS_INF_EXPIRING; + smp_mb(); + ino->flags &= ~AUTOFS_INF_NO_RCU; init_completion(&ino->expire_complete); spin_unlock(&sbi->fs_lock); spin_lock(&sbi->lookup_lock); @@ -476,11 +503,14 @@ int autofs4_expire_wait(struct dentry *dentry, int rcu_walk) int status; /* Block on any pending expire */ + if (!(ino->flags & (AUTOFS_INF_EXPIRING | AUTOFS_INF_NO_RCU))) + return 0; + if (rcu_walk) + return -ECHILD; + spin_lock(&sbi->fs_lock); if (ino->flags & AUTOFS_INF_EXPIRING) { spin_unlock(&sbi->fs_lock); - if (rcu_walk) - return -ECHILD; DPRINTK("waiting for expire %p name=%.*s", dentry, dentry->d_name.len, dentry->d_name.name); |