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Commit 9b1e3afd authored by Ian Kent's avatar Ian Kent Committed by Linus Torvalds
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[PATCH] autofs4: avoid panic on bind mount of autofs owned directory 



While this is not a solution to bind and move mounts on autofs owned
directories it is necessary to fix the trady error handling.

At least it avoids the kernel panic I observed checking out bug #4589.

Signed-off-by: default avatarIan Kent <raven@themaw.net>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 88187605

fs/autofs4/autofs_i.h

+13 −0
Original line number Diff line number Diff line
@@ -185,6 +185,19 @@ int autofs4_wait(struct autofs_sb_info *,struct dentry *, enum autofs_notify); 
int autofs4_wait_release(struct autofs_sb_info *,autofs_wqt_t,int);

void autofs4_catatonic_mode(struct autofs_sb_info *);



static inline int autofs4_follow_mount(struct vfsmount **mnt, struct dentry **dentry)

{

	int res = 0;



	while (d_mountpoint(*dentry)) {

		int followed = follow_down(mnt, dentry);

		if (!followed)

			break;

		res = 1;

	}

	return res;

}



static inline int simple_positive(struct dentry *dentry)

{

	return dentry->d_inode && !d_unhashed(dentry);

fs/autofs4/expire.c

+1 −4
Original line number Diff line number Diff line
@@ -56,12 +56,9 @@ static int autofs4_check_mount(struct vfsmount *mnt, struct dentry *dentry) 
	mntget(mnt);

	dget(dentry);



	if (!follow_down(&mnt, &dentry))

	if (!autofs4_follow_mount(&mnt, &dentry))

		goto done;



	while (d_mountpoint(dentry) && follow_down(&mnt, &dentry))

		;



	/* This is an autofs submount, we can't expire it */

	if (is_autofs4_dentry(dentry))

		goto done;

fs/autofs4/root.c

+5 −1
Original line number Diff line number Diff line
@@ -205,7 +205,11 @@ static int autofs4_dir_open(struct inode *inode, struct file *file) 
		struct vfsmount *fp_mnt = mntget(mnt);

		struct dentry *fp_dentry = dget(dentry);



		while (follow_down(&fp_mnt, &fp_dentry) && d_mountpoint(fp_dentry));

		if (!autofs4_follow_mount(&fp_mnt, &fp_dentry)) {

			dput(fp_dentry);

			mntput(fp_mnt);

			return -ENOENT;

		}



		fp = dentry_open(fp_dentry, fp_mnt, file->f_flags);

		status = PTR_ERR(fp);