diff options
Diffstat (limited to 'fs/autofs4')
| -rw-r--r-- | fs/autofs4/autofs_i.h | 2 | ||||
| -rw-r--r-- | fs/autofs4/dev-ioctl.c | 2 | ||||
| -rw-r--r-- | fs/autofs4/expire.c | 4 | ||||
| -rw-r--r-- | fs/autofs4/root.c | 44 |
4 files changed, 34 insertions, 18 deletions
diff --git a/fs/autofs4/autofs_i.h b/fs/autofs4/autofs_i.h index 9e359fb20c0a..2f1032f12d91 100644 --- a/fs/autofs4/autofs_i.h +++ b/fs/autofs4/autofs_i.h @@ -148,7 +148,7 @@ void autofs4_free_ino(struct autofs_info *); /* Expiration */ int is_autofs4_dentry(struct dentry *); -int autofs4_expire_wait(struct dentry *dentry); +int autofs4_expire_wait(struct dentry *dentry, int rcu_walk); int autofs4_expire_run(struct super_block *, struct vfsmount *, struct autofs_sb_info *, struct autofs_packet_expire __user *); diff --git a/fs/autofs4/dev-ioctl.c b/fs/autofs4/dev-ioctl.c index 5b570b6efa28..aaf96cb25452 100644 --- a/fs/autofs4/dev-ioctl.c +++ b/fs/autofs4/dev-ioctl.c @@ -450,7 +450,7 @@ static int autofs_dev_ioctl_requester(struct file *fp, ino = autofs4_dentry_ino(path.dentry); if (ino) { err = 0; - autofs4_expire_wait(path.dentry); + autofs4_expire_wait(path.dentry, 0); spin_lock(&sbi->fs_lock); param->requester.uid = from_kuid_munged(current_user_ns(), ino->uid); param->requester.gid = from_kgid_munged(current_user_ns(), ino->gid); diff --git a/fs/autofs4/expire.c b/fs/autofs4/expire.c index 8fa3895cda02..1695eda8ac18 100644 --- a/fs/autofs4/expire.c +++ b/fs/autofs4/expire.c @@ -461,7 +461,7 @@ found: return expired; } -int autofs4_expire_wait(struct dentry *dentry) +int autofs4_expire_wait(struct dentry *dentry, int rcu_walk) { struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb); struct autofs_info *ino = autofs4_dentry_ino(dentry); @@ -471,6 +471,8 @@ int autofs4_expire_wait(struct dentry *dentry) 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); diff --git a/fs/autofs4/root.c b/fs/autofs4/root.c index cdb25ebccc4c..2296c8301b66 100644 --- a/fs/autofs4/root.c +++ b/fs/autofs4/root.c @@ -210,7 +210,8 @@ next: return NULL; } -static struct dentry *autofs4_lookup_expiring(struct dentry *dentry) +static struct dentry *autofs4_lookup_expiring(struct dentry *dentry, + bool rcu_walk) { struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb); struct dentry *parent = dentry->d_parent; @@ -229,6 +230,11 @@ static struct dentry *autofs4_lookup_expiring(struct dentry *dentry) struct dentry *expiring; struct qstr *qstr; + if (rcu_walk) { + spin_unlock(&sbi->lookup_lock); + return ERR_PTR(-ECHILD); + } + ino = list_entry(p, struct autofs_info, expiring); expiring = ino->dentry; @@ -264,13 +270,15 @@ next: return NULL; } -static int autofs4_mount_wait(struct dentry *dentry) +static int autofs4_mount_wait(struct dentry *dentry, bool rcu_walk) { struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb); struct autofs_info *ino = autofs4_dentry_ino(dentry); int status = 0; if (ino->flags & AUTOFS_INF_PENDING) { + if (rcu_walk) + return -ECHILD; DPRINTK("waiting for mount name=%.*s", dentry->d_name.len, dentry->d_name.name); status = autofs4_wait(sbi, dentry, NFY_MOUNT); @@ -280,20 +288,22 @@ static int autofs4_mount_wait(struct dentry *dentry) return status; } -static int do_expire_wait(struct dentry *dentry) +static int do_expire_wait(struct dentry *dentry, bool rcu_walk) { struct dentry *expiring; - expiring = autofs4_lookup_expiring(dentry); + expiring = autofs4_lookup_expiring(dentry, rcu_walk); + if (IS_ERR(expiring)) + return PTR_ERR(expiring); if (!expiring) - return autofs4_expire_wait(dentry); + return autofs4_expire_wait(dentry, rcu_walk); else { /* * If we are racing with expire the request might not * be quite complete, but the directory has been removed * so it must have been successful, just wait for it. */ - autofs4_expire_wait(expiring); + autofs4_expire_wait(expiring, 0); autofs4_del_expiring(expiring); dput(expiring); } @@ -345,7 +355,7 @@ static struct vfsmount *autofs4_d_automount(struct path *path) * and the directory was removed, so just go ahead and try * the mount. */ - status = do_expire_wait(dentry); + status = do_expire_wait(dentry, 0); if (status && status != -EAGAIN) return NULL; @@ -353,7 +363,7 @@ static struct vfsmount *autofs4_d_automount(struct path *path) spin_lock(&sbi->fs_lock); if (ino->flags & AUTOFS_INF_PENDING) { spin_unlock(&sbi->fs_lock); - status = autofs4_mount_wait(dentry); + status = autofs4_mount_wait(dentry, 0); if (status) return ERR_PTR(status); goto done; @@ -394,7 +404,7 @@ static struct vfsmount *autofs4_d_automount(struct path *path) } ino->flags |= AUTOFS_INF_PENDING; spin_unlock(&sbi->fs_lock); - status = autofs4_mount_wait(dentry); + status = autofs4_mount_wait(dentry, 0); spin_lock(&sbi->fs_lock); ino->flags &= ~AUTOFS_INF_PENDING; if (status) { @@ -430,21 +440,25 @@ static int autofs4_d_manage(struct dentry *dentry, bool rcu_walk) return 0; } - /* We need to sleep, so we need pathwalk to be in ref-mode */ - if (rcu_walk) - return -ECHILD; - /* Wait for pending expires */ - do_expire_wait(dentry); + if (do_expire_wait(dentry, rcu_walk) == -ECHILD) + return -ECHILD; /* * This dentry may be under construction so wait on mount * completion. */ - status = autofs4_mount_wait(dentry); + status = autofs4_mount_wait(dentry, rcu_walk); if (status) return status; + if (rcu_walk) + /* it is always safe to return 0 as the worst that + * will happen is we retry in REF-walk mode. + * Better than always taking a lock. + */ + return 0; + spin_lock(&sbi->fs_lock); /* * If the dentry has been selected for expire while we slept |