From: Miklos Szeredi Subject: Re: ext4_file_open: Inconsistent encryption contexts (commit ff978b09f973) breaking Docker Date: Mon, 14 Mar 2016 11:27:35 +0100 Message-ID: <20160314102735.GM8655@tucsk> References: <87io0t3ks9.fsf@gamma.ozlabs.ibm.com> <20160311021506.GA32214@thunk.org> <20160311153403.GJ8655@tucsk> <87ziu1eetp.fsf@gamma.ozlabs.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Theodore Ts'o , linux-kernel@vger.kernel.org, linux-ext4@vger.kernel.org, viro@zeniv.linux.org.uk, linux-unionfs@vger.kernel.org To: Daniel Axtens Return-path: Content-Disposition: inline In-Reply-To: <87ziu1eetp.fsf@gamma.ozlabs.ibm.com> Sender: linux-unionfs-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org On Mon, Mar 14, 2016 at 05:47:14PM +1100, Daniel Axtens wrote: > Hi all, > > To make sure I wasn't crazy, I installed a mainline kernel on my x86 laptop. > > It also doesn't work there, but I do get a far more detailed set of > backtraces, which I've added below. It also means it's not powerpc > specific, which should help in debugging it. Hi Daniel, Could you please try the below patch? It's actually three patches rolled into one: 1) ext4: use dget_parent() in ext4_file_open() Even with dget_parent() we don't hold i_mutex on directory and so the file could be moved in the mean time. Not sure if it's a problem. Ted? 2) vfs: add file_dentry() Posted here: http://marc.info/?l=linux-fsdevel&m=145745197615687&w=2 3) ext4: use file_dentry() s/\([a-z_]*\)->f_path\.dentry/file_dentry(\1)/ Thanks, Miklos diff --git a/fs/ext4/file.c b/fs/ext4/file.c index 4cd318f31cbe..38847f38b34a 100644 --- a/fs/ext4/file.c +++ b/fs/ext4/file.c @@ -335,7 +335,7 @@ static int ext4_file_open(struct inode * inode, struct file * filp) struct super_block *sb = inode->i_sb; struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); struct vfsmount *mnt = filp->f_path.mnt; - struct inode *dir = filp->f_path.dentry->d_parent->d_inode; + struct dentry *dir; struct path path; char buf[64], *cp; int ret; @@ -379,14 +379,18 @@ static int ext4_file_open(struct inode * inode, struct file * filp) if (ext4_encryption_info(inode) == NULL) return -ENOKEY; } - if (ext4_encrypted_inode(dir) && - !ext4_is_child_context_consistent_with_parent(dir, inode)) { + + dir = dget_parent(file_dentry(filp)); + if (ext4_encrypted_inode(d_inode(dir)) && + !ext4_is_child_context_consistent_with_parent(d_inode(dir), inode)) { ext4_warning(inode->i_sb, "Inconsistent encryption contexts: %lu/%lu\n", - (unsigned long) dir->i_ino, + (unsigned long) d_inode(dir)->i_ino, (unsigned long) inode->i_ino); + dput(dir); return -EPERM; } + dput(dir); /* * Set up the jbd2_inode if we are opening the inode for * writing and the journal is present diff --git a/fs/open.c b/fs/open.c index 55bdc75e2172..6326c11eda78 100644 --- a/fs/open.c +++ b/fs/open.c @@ -831,6 +831,17 @@ char *file_path(struct file *filp, char *buf, int buflen) } EXPORT_SYMBOL(file_path); +struct dentry *file_dentry(const struct file *file) +{ + struct dentry *dentry = file->f_path.dentry; + + if (likely(d_inode(dentry) == file_inode(file))) + return dentry; + else + return dentry->d_op->d_native_dentry(dentry, file_inode(file)); +} +EXPORT_SYMBOL(file_dentry); + /** * vfs_open - open the file at the given path * @path: path to open diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c index 619ad4b016d2..5142aa2034c4 100644 --- a/fs/overlayfs/super.c +++ b/fs/overlayfs/super.c @@ -336,14 +336,30 @@ static int ovl_dentry_weak_revalidate(struct dentry *dentry, unsigned int flags) return ret; } +static struct dentry *ovl_d_native_dentry(struct dentry *dentry, + struct inode *inode) +{ + struct ovl_entry *oe = dentry->d_fsdata; + struct dentry *realentry = ovl_upperdentry_dereference(oe); + + if (realentry && inode == d_inode(realentry)) + return realentry; + realentry = __ovl_dentry_lower(oe); + if (realentry && inode == d_inode(realentry)) + return realentry; + BUG(); +} + static const struct dentry_operations ovl_dentry_operations = { .d_release = ovl_dentry_release, .d_select_inode = ovl_d_select_inode, + .d_native_dentry = ovl_d_native_dentry, }; static const struct dentry_operations ovl_reval_dentry_operations = { .d_release = ovl_dentry_release, .d_select_inode = ovl_d_select_inode, + .d_native_dentry = ovl_d_native_dentry, .d_revalidate = ovl_dentry_revalidate, .d_weak_revalidate = ovl_dentry_weak_revalidate, }; diff --git a/include/linux/dcache.h b/include/linux/dcache.h index c4b5f4b3f8f8..99ecb6de636c 100644 --- a/include/linux/dcache.h +++ b/include/linux/dcache.h @@ -161,6 +161,7 @@ struct dentry_operations { struct vfsmount *(*d_automount)(struct path *); int (*d_manage)(struct dentry *, bool); struct inode *(*d_select_inode)(struct dentry *, unsigned); + struct dentry *(*d_native_dentry)(struct dentry *, struct inode *); } ____cacheline_aligned; /* diff --git a/include/linux/fs.h b/include/linux/fs.h index ae681002100a..1091d9f43271 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1234,6 +1234,8 @@ static inline struct inode *file_inode(const struct file *f) return f->f_inode; } +extern struct dentry *file_dentry(const struct file *file); + static inline int locks_lock_file_wait(struct file *filp, struct file_lock *fl) { return locks_lock_inode_wait(file_inode(filp), fl);