ovl: Revert changes in 4.1.5-1 due to regression (Reopens: #786925)

In particular, "fix a braino in ovl_d_select_inode()" introduced a
type error and potential crash because we still have ovl_dentry_open()
not ovl_d_select_inode().  Doing this properly requires an ABI change.

5 files changed, 1 insertions, 308 deletions

diff --git a/debian/changelog b/debian/changelog
index 4315a596bfc8..1870577eda4b 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -53,6 +53,7 @@ linux (4.1.6-1) UNRELEASED; urgency=medium
   * [i386] udeb: Make gpio_keys_polled and leds-gpio optional in input-modules
     as they are not built for the 686-pae flavour (fixes FTBFS)
   * perf: Fix AUX buffer refcounting
+  * ovl: Revert changes in 4.1.5-1 due to regression (Reopens: #786925)
 
  -- Aurelien Jarno <aurel32@debian.org>  Tue, 18 Aug 2015 11:35:05 +0200
 
diff --git a/debian/patches/bugfix/all/-ovl-don-t-traverse-automount-points.patch b/debian/patches/bugfix/all/-ovl-don-t-traverse-automount-points.patch
deleted file mode 100644
index 84a92514f3ba..000000000000
--- a/debian/patches/bugfix/all/-ovl-don-t-traverse-automount-points.patch
+++ /dev/null
@@ -1,50 +0,0 @@
-From: Miklos Szeredi <mszeredi@suse.cz>
-Date: Mon, 22 Jun 2015 13:53:48 +0200
-Subject: ovl: don't traverse automount points
-Origin: https://git.kernel.org/linus/a6f15d9a756571babbb2b2cd4fdd1b64a5de232b
-Bug-Debian: https://bugs.debian.org/786925
-
-NFS and other distributed filesystems may place automount points in the
-tree.  Previoulsy overlayfs refused to mount such filesystems types (based
-on the existence of the .d_automount callback), even if the actual export
-didn't have any automount points.
-
-It cannot be determined in advance whether the filesystem has automount
-points or not.  The solution is to allow fs with .d_automount but refuse to
-traverse any automount points encountered.
-
-Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
----
- fs/overlayfs/super.c | 8 ++++++--
- 1 file changed, 6 insertions(+), 2 deletions(-)
-
-diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
-index bf8537c..de9d2ee 100644
---- a/fs/overlayfs/super.c
-+++ b/fs/overlayfs/super.c
-@@ -303,6 +303,10 @@ static inline struct dentry *ovl_lookup_real(struct dentry *dir,
- 	} else if (!dentry->d_inode) {
- 		dput(dentry);
- 		dentry = NULL;
-+	} else if (dentry->d_flags & DCACHE_MANAGED_DENTRY) {
-+		dput(dentry);
-+		/* Don't support traversing automounts */
-+		dentry = ERR_PTR(-EREMOTE);
- 	}
- 	return dentry;
- }
-@@ -700,12 +704,12 @@ static bool ovl_is_allowed_fs_type(struct dentry *root)
- 
- 	/*
- 	 * We don't support:
--	 *  - automount filesystems
-+	 *  - autofs
- 	 *  - filesystems with revalidate (FIXME for lower layer)
- 	 *  - filesystems with case insensitive names
- 	 */
- 	if (dop &&
--	    (dop->d_manage || dop->d_automount ||
-+	    (dop->d_manage ||
- 	     dop->d_revalidate || dop->d_weak_revalidate ||
- 	     dop->d_compare || dop->d_hash)) {
- 		return false;
diff --git a/debian/patches/bugfix/all/fix-a-braino-in-ovl_d_select_inode.patch b/debian/patches/bugfix/all/fix-a-braino-in-ovl_d_select_inode.patch
deleted file mode 100644
index 903118e94e53..000000000000
--- a/debian/patches/bugfix/all/fix-a-braino-in-ovl_d_select_inode.patch
+++ /dev/null
@@ -1,28 +0,0 @@
-From: Al Viro <viro@zeniv.linux.org.uk>
-Date: Sun, 12 Jul 2015 10:39:45 -0400
-Subject: fix a braino in ovl_d_select_inode()
-Origin: https://git.kernel.org/linus/9391dd00d13c853ab4f2a85435288ae2202e0e43
-Bug-Debian: https://bugs.debian.org/786925
-
-when opening a directory we want the overlayfs inode, not one from
-the topmost layer.
-
-Reported-By: Andrey Jr. Melnikov <temnota.am@gmail.com>
-Tested-By: Andrey Jr. Melnikov <temnota.am@gmail.com>
-Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
----
- fs/overlayfs/inode.c | 3 +++
- 1 file changed, 3 insertions(+)
-
---- a/fs/overlayfs/inode.c
-+++ b/fs/overlayfs/inode.c
-@@ -344,6 +344,9 @@ static int ovl_dentry_open(struct dentry
- 	enum ovl_path_type type;
- 	bool want_write = false;
- 
-+	if (d_is_dir(dentry))
-+		return d_backing_inode(dentry);
-+
- 	type = ovl_path_real(dentry, &realpath);
- 	if (ovl_open_need_copy_up(file->f_flags, type, realpath.dentry)) {
- 		want_write = true;
diff --git a/debian/patches/bugfix/all/ovl-allow-distributed-fs-as-lower-layer.patch b/debian/patches/bugfix/all/ovl-allow-distributed-fs-as-lower-layer.patch
deleted file mode 100644
index 66976e29280f..000000000000
--- a/debian/patches/bugfix/all/ovl-allow-distributed-fs-as-lower-layer.patch
+++ /dev/null
@@ -1,227 +0,0 @@
-From: Miklos Szeredi <mszeredi@suse.cz>
-Date: Mon, 22 Jun 2015 13:53:48 +0200
-Subject: ovl: allow distributed fs as lower layer
-Origin: https://git.kernel.org/linus/7c03b5d45b8eebf0111125053d8fe887cc262ba6
-Bug-Debian: https://bugs.debian.org/786925
-
-Allow filesystems with .d_revalidate as lower layer(s), but not as upper
-layer.
-
-For local filesystems the rule was that modifications on the layers
-directly while being part of the overlay results in undefined behavior.
-
-This can easily be extended to distributed filesystems: we assume the tree
-used as lower layer is static, which means ->d_revalidate() should always
-return "1".  If that is not the case, return -ESTALE, don't try to work
-around the modification.
-
-Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
----
- fs/overlayfs/super.c | 113 +++++++++++++++++++++++++++++++++++++++------------
- 1 file changed, 88 insertions(+), 25 deletions(-)
-
-diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
-index de9d2ee..8a08c58 100644
---- a/fs/overlayfs/super.c
-+++ b/fs/overlayfs/super.c
-@@ -273,10 +273,57 @@ static void ovl_dentry_release(struct dentry *dentry)
- 	}
- }
- 
-+static int ovl_dentry_revalidate(struct dentry *dentry, unsigned int flags)
-+{
-+	struct ovl_entry *oe = dentry->d_fsdata;
-+	unsigned int i;
-+	int ret = 1;
-+
-+	for (i = 0; i < oe->numlower; i++) {
-+		struct dentry *d = oe->lowerstack[i].dentry;
-+
-+		if (d->d_flags & DCACHE_OP_REVALIDATE) {
-+			ret = d->d_op->d_revalidate(d, flags);
-+			if (ret < 0)
-+				return ret;
-+			if (!ret) {
-+				if (!(flags & LOOKUP_RCU))
-+					d_invalidate(d);
-+				return -ESTALE;
-+			}
-+		}
-+	}
-+	return 1;
-+}
-+
-+static int ovl_dentry_weak_revalidate(struct dentry *dentry, unsigned int flags)
-+{
-+	struct ovl_entry *oe = dentry->d_fsdata;
-+	unsigned int i;
-+	int ret = 1;
-+
-+	for (i = 0; i < oe->numlower; i++) {
-+		struct dentry *d = oe->lowerstack[i].dentry;
-+
-+		if (d->d_flags & DCACHE_OP_WEAK_REVALIDATE) {
-+			ret = d->d_op->d_weak_revalidate(d, flags);
-+			if (ret <= 0)
-+				break;
-+		}
-+	}
-+	return ret;
-+}
-+
- static const struct dentry_operations ovl_dentry_operations = {
- 	.d_release = ovl_dentry_release,
- };
- 
-+static const struct dentry_operations ovl_reval_dentry_operations = {
-+	.d_release = ovl_dentry_release,
-+	.d_revalidate = ovl_dentry_revalidate,
-+	.d_weak_revalidate = ovl_dentry_weak_revalidate,
-+};
-+
- static struct ovl_entry *ovl_alloc_entry(unsigned int numlower)
- {
- 	size_t size = offsetof(struct ovl_entry, lowerstack[numlower]);
-@@ -288,6 +335,20 @@ static struct ovl_entry *ovl_alloc_entry(unsigned int numlower)
- 	return oe;
- }
- 
-+static bool ovl_dentry_remote(struct dentry *dentry)
-+{
-+	return dentry->d_flags &
-+		(DCACHE_OP_REVALIDATE | DCACHE_OP_WEAK_REVALIDATE);
-+}
-+
-+static bool ovl_dentry_weird(struct dentry *dentry)
-+{
-+	return dentry->d_flags & (DCACHE_NEED_AUTOMOUNT |
-+				  DCACHE_MANAGE_TRANSIT |
-+				  DCACHE_OP_HASH |
-+				  DCACHE_OP_COMPARE);
-+}
-+
- static inline struct dentry *ovl_lookup_real(struct dentry *dir,
- 					     struct qstr *name)
- {
-@@ -303,9 +364,9 @@ static inline struct dentry *ovl_lookup_real(struct dentry *dir,
- 	} else if (!dentry->d_inode) {
- 		dput(dentry);
- 		dentry = NULL;
--	} else if (dentry->d_flags & DCACHE_MANAGED_DENTRY) {
-+	} else if (ovl_dentry_weird(dentry)) {
- 		dput(dentry);
--		/* Don't support traversing automounts */
-+		/* Don't support traversing automounts and other weirdness */
- 		dentry = ERR_PTR(-EREMOTE);
- 	}
- 	return dentry;
-@@ -354,6 +415,11 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
- 			goto out;
- 
- 		if (this) {
-+			if (unlikely(ovl_dentry_remote(this))) {
-+				dput(this);
-+				err = -EREMOTE;
-+				goto out;
-+			}
- 			if (ovl_is_whiteout(this)) {
- 				dput(this);
- 				this = NULL;
-@@ -698,25 +764,6 @@ static void ovl_unescape(char *s)
- 	}
- }
- 
--static bool ovl_is_allowed_fs_type(struct dentry *root)
--{
--	const struct dentry_operations *dop = root->d_op;
--
--	/*
--	 * We don't support:
--	 *  - autofs
--	 *  - filesystems with revalidate (FIXME for lower layer)
--	 *  - filesystems with case insensitive names
--	 */
--	if (dop &&
--	    (dop->d_manage ||
--	     dop->d_revalidate || dop->d_weak_revalidate ||
--	     dop->d_compare || dop->d_hash)) {
--		return false;
--	}
--	return true;
--}
--
- static int ovl_mount_dir_noesc(const char *name, struct path *path)
- {
- 	int err = -EINVAL;
-@@ -731,7 +778,7 @@ static int ovl_mount_dir_noesc(const char *name, struct path *path)
- 		goto out;
- 	}
- 	err = -EINVAL;
--	if (!ovl_is_allowed_fs_type(path->dentry)) {
-+	if (ovl_dentry_weird(path->dentry)) {
- 		pr_err("overlayfs: filesystem on '%s' not supported\n", name);
- 		goto out_put;
- 	}
-@@ -755,13 +802,21 @@ static int ovl_mount_dir(const char *name, struct path *path)
- 	if (tmp) {
- 		ovl_unescape(tmp);
- 		err = ovl_mount_dir_noesc(tmp, path);
-+
-+		if (!err)
-+			if (ovl_dentry_remote(path->dentry)) {
-+				pr_err("overlayfs: filesystem on '%s' not supported as upperdir\n",
-+				       tmp);
-+				path_put(path);
-+				err = -EINVAL;
-+			}
- 		kfree(tmp);
- 	}
- 	return err;
- }
- 
- static int ovl_lower_dir(const char *name, struct path *path, long *namelen,
--			 int *stack_depth)
-+			 int *stack_depth, bool *remote)
- {
- 	int err;
- 	struct kstatfs statfs;
-@@ -778,6 +833,9 @@ static int ovl_lower_dir(const char *name, struct path *path, long *namelen,
- 	*namelen = max(*namelen, statfs.f_namelen);
- 	*stack_depth = max(*stack_depth, path->mnt->mnt_sb->s_stack_depth);
- 
-+	if (ovl_dentry_remote(path->dentry))
-+		*remote = true;
-+
- 	return 0;
- 
- out_put:
-@@ -831,6 +889,7 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
- 	unsigned int numlower;
- 	unsigned int stacklen = 0;
- 	unsigned int i;
-+	bool remote = false;
- 	int err;
- 
- 	err = -ENOMEM;
-@@ -904,7 +963,8 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
- 	lower = lowertmp;
- 	for (numlower = 0; numlower < stacklen; numlower++) {
- 		err = ovl_lower_dir(lower, &stack[numlower],
--				    &ufs->lower_namelen, &sb->s_stack_depth);
-+				    &ufs->lower_namelen, &sb->s_stack_depth,
-+				    &remote);
- 		if (err)
- 			goto out_put_lowerpath;
- 
-@@ -962,7 +1022,10 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
- 	if (!ufs->upper_mnt)
- 		sb->s_flags |= MS_RDONLY;
- 
--	sb->s_d_op = &ovl_dentry_operations;
-+	if (remote)
-+		sb->s_d_op = &ovl_reval_dentry_operations;
-+	else
-+		sb->s_d_op = &ovl_dentry_operations;
- 
- 	err = -ENOMEM;
- 	oe = ovl_alloc_entry(numlower);
diff --git a/debian/patches/series b/debian/patches/series
index e54bbb606c82..eea0a6b99069 100644
--- a/debian/patches/series
+++ b/debian/patches/series
@@ -87,8 +87,5 @@ features/all/grsecurity/grsecurity-kconfig.patch
 #features/all/grsecurity/grsecurity-kbuild.patch
 features/all/grsecurity/grkernsec_perf_harden.patch
 bugfix/all/virtio-net-drop-netif_f_fraglist.patch
-bugfix/all/-ovl-don-t-traverse-automount-points.patch
-bugfix/all/ovl-allow-distributed-fs-as-lower-layer.patch
-bugfix/all/fix-a-braino-in-ovl_d_select_inode.patch
 bugfix/all/perf-fix-aux-buffer-refcounting.patch
 bugfix/all/perf-fix-double-free-of-the-aux-buffer.patch