From 60359741473438f66fef7297d1fa2435640dbe79 Mon Sep 17 00:00:00 2001 From: Ian Kent Date: Thu, 24 Nov 2016 08:03:42 +1100 Subject: autofs: use path_has_submounts() to fix unreliable have_submount() checks If an automount mount is clone(2)ed into a file system that is propagation private, when it later expires in the originating namespace, subsequent calls to autofs ->d_automount() for that dentry in the original namespace will return ELOOP until the mount is umounted in the cloned namespace. Now that a struct path is available where needed use path_has_submounts() instead of have_submounts() so we don't get false positives when checking if a dentry is a mount point or contains mounts in the current namespace. Link: http://lkml.kernel.org/r/20161011053423.27645.91233.stgit@pluto.themaw.net Signed-off-by: Ian Kent Cc: Al Viro Cc: Eric W. Biederman Cc: Omar Sandoval Signed-off-by: Andrew Morton Signed-off-by: Al Viro --- fs/autofs4/dev-ioctl.c | 2 +- fs/autofs4/root.c | 14 +++++++------- fs/autofs4/waitq.c | 10 +++++++--- 3 files changed, 15 insertions(+), 11 deletions(-) (limited to 'fs/autofs4') diff --git a/fs/autofs4/dev-ioctl.c b/fs/autofs4/dev-ioctl.c index 40c69f91dc0a..afacdaa8dd5a 100644 --- a/fs/autofs4/dev-ioctl.c +++ b/fs/autofs4/dev-ioctl.c @@ -575,7 +575,7 @@ static int autofs_dev_ioctl_ismountpoint(struct file *fp, devid = new_encode_dev(dev); - err = have_submounts(path.dentry); + err = path_has_submounts(&path); if (follow_down_one(&path)) magic = path.dentry->d_sb->s_magic; diff --git a/fs/autofs4/root.c b/fs/autofs4/root.c index 9355608cb495..ce4e6216a5f0 100644 --- a/fs/autofs4/root.c +++ b/fs/autofs4/root.c @@ -384,16 +384,16 @@ static struct vfsmount *autofs4_d_automount(struct path *path) /* * It's possible that user space hasn't removed directories * after umounting a rootless multi-mount, although it - * should. For v5 have_submounts() is sufficient to handle - * this because the leaves of the directory tree under the - * mount never trigger mounts themselves (they have an autofs - * trigger mount mounted on them). But v4 pseudo direct mounts - * do need the leaves to trigger mounts. In this case we - * have no choice but to use the list_empty() check and + * should. For v5 path_has_submounts() is sufficient to + * handle this because the leaves of the directory tree under + * the mount never trigger mounts themselves (they have an + * autofs trigger mount mounted on them). But v4 pseudo direct + * mounts do need the leaves to trigger mounts. In this case + * we have no choice but to use the list_empty() check and * require user space behave. */ if (sbi->version > 4) { - if (have_submounts(dentry)) { + if (path_has_submounts(path)) { spin_unlock(&sbi->fs_lock); goto done; } diff --git a/fs/autofs4/waitq.c b/fs/autofs4/waitq.c index 38ef973f80e9..1278335ce366 100644 --- a/fs/autofs4/waitq.c +++ b/fs/autofs4/waitq.c @@ -250,8 +250,9 @@ autofs4_find_wait(struct autofs_sb_info *sbi, const struct qstr *qstr) static int validate_request(struct autofs_wait_queue **wait, struct autofs_sb_info *sbi, const struct qstr *qstr, - struct dentry *dentry, enum autofs_notify notify) + const struct path *path, enum autofs_notify notify) { + struct dentry *dentry = path->dentry; struct autofs_wait_queue *wq; struct autofs_info *ino; @@ -314,6 +315,7 @@ static int validate_request(struct autofs_wait_queue **wait, */ if (notify == NFY_MOUNT) { struct dentry *new = NULL; + struct path this; int valid = 1; /* @@ -333,7 +335,9 @@ static int validate_request(struct autofs_wait_queue **wait, dentry = new; } } - if (have_submounts(dentry)) + this.mnt = path->mnt; + this.dentry = dentry; + if (path_has_submounts(&this)) valid = 0; if (new) @@ -406,7 +410,7 @@ int autofs4_wait(struct autofs_sb_info *sbi, return -EINTR; } - ret = validate_request(&wq, sbi, &qstr, dentry, notify); + ret = validate_request(&wq, sbi, &qstr, path, notify); if (ret <= 0) { if (ret != -EINTR) mutex_unlock(&sbi->wq_mutex); -- cgit v1.2.3