autofs: use path_is_mountpoint() to fix unreliable d_mountpoint() 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_is_mountpoint() instead of d_mountpoint() so we don't get false positives when checking if a dentry is a mount point in the current namespace. Link: http://lkml.kernel.org/r/20161011053418.27645.15241.stgit@pluto.themaw.net Signed-off-by: Ian Kent <raven@themaw.net> Cc: Al Viro <viro@ZenIV.linux.org.uk> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Omar Sandoval <osandov@osandov.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>zero-colors
parent
dd36a882e7
commit
cfaf86ab6c
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@ -123,7 +123,7 @@ static int autofs4_dir_open(struct inode *inode, struct file *file)
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* it.
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* it.
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*/
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*/
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spin_lock(&sbi->lookup_lock);
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spin_lock(&sbi->lookup_lock);
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if (!d_mountpoint(dentry) && simple_empty(dentry)) {
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if (!path_is_mountpoint(&file->f_path) && simple_empty(dentry)) {
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spin_unlock(&sbi->lookup_lock);
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spin_unlock(&sbi->lookup_lock);
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return -ENOENT;
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return -ENOENT;
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}
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}
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@ -372,15 +372,15 @@ static struct vfsmount *autofs4_d_automount(struct path *path)
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/*
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/*
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* If the dentry is a symlink it's equivalent to a directory
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* If the dentry is a symlink it's equivalent to a directory
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* having d_mountpoint() true, so there's no need to call back
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* having path_is_mountpoint() true, so there's no need to call
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* to the daemon.
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* back to the daemon.
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*/
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*/
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if (d_really_is_positive(dentry) && d_is_symlink(dentry)) {
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if (d_really_is_positive(dentry) && d_is_symlink(dentry)) {
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spin_unlock(&sbi->fs_lock);
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spin_unlock(&sbi->fs_lock);
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goto done;
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goto done;
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}
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}
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if (!d_mountpoint(dentry)) {
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if (!path_is_mountpoint(path)) {
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/*
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/*
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* It's possible that user space hasn't removed directories
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* It's possible that user space hasn't removed directories
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* after umounting a rootless multi-mount, although it
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* after umounting a rootless multi-mount, although it
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@ -434,7 +434,7 @@ static int autofs4_d_manage(const struct path *path, bool rcu_walk)
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/* The daemon never waits. */
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/* The daemon never waits. */
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if (autofs4_oz_mode(sbi)) {
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if (autofs4_oz_mode(sbi)) {
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if (!d_mountpoint(dentry))
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if (!path_is_mountpoint(path))
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return -EISDIR;
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return -EISDIR;
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return 0;
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return 0;
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}
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}
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@ -463,7 +463,7 @@ static int autofs4_d_manage(const struct path *path, bool rcu_walk)
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if (ino->flags & AUTOFS_INF_WANT_EXPIRE)
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if (ino->flags & AUTOFS_INF_WANT_EXPIRE)
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return 0;
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return 0;
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if (d_mountpoint(dentry))
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if (path_is_mountpoint(path))
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return 0;
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return 0;
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inode = d_inode_rcu(dentry);
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inode = d_inode_rcu(dentry);
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if (inode && S_ISLNK(inode->i_mode))
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if (inode && S_ISLNK(inode->i_mode))
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@ -490,7 +490,7 @@ static int autofs4_d_manage(const struct path *path, bool rcu_walk)
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* we can avoid needless calls ->d_automount() and avoid
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* we can avoid needless calls ->d_automount() and avoid
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* an incorrect ELOOP error return.
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* an incorrect ELOOP error return.
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*/
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*/
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if ((!d_mountpoint(dentry) && !simple_empty(dentry)) ||
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if ((!path_is_mountpoint(path) && !simple_empty(dentry)) ||
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(d_really_is_positive(dentry) && d_is_symlink(dentry)))
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(d_really_is_positive(dentry) && d_is_symlink(dentry)))
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status = -EISDIR;
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status = -EISDIR;
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}
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}
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