android-5.4/ANDROID-vfs-Add-setattr2-for-filesystems-with-per-mount-permissions.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Daniel Rosenberg <drosen@google.com>
Date: Wed, 26 Oct 2016 16:33:11 -0700
Subject: ANDROID: vfs: Add setattr2 for filesystems with per mount permissions

This allows filesystems to use their mount private data to
influence the permssions they use in setattr2. It has
been separated into a new call to avoid disrupting current
setattr users.

Test: HiKey/X15 + Pie + android-mainline,
      and HiKey + AOSP Maser + android-mainline,
      directories under /sdcard created,
      output of mount is right,
      CTS test collecting device infor works

Change-Id: I19959038309284448f1b7f232d579674ef546385
Signed-off-by: Daniel Rosenberg <drosen@google.com>
Signed-off-by: Yongqin Liu <yongqin.liu@linaro.org>
---
 fs/attr.c          | 12 ++++++++++--
 fs/coredump.c      |  2 +-
 fs/inode.c         |  6 +++---
 fs/namei.c         |  2 +-
 fs/open.c          | 23 ++++++++++++++++-------
 fs/utimes.c        |  2 +-
 include/linux/fs.h |  6 +++++-
 7 files changed, 37 insertions(+), 16 deletions(-)

diff --git a/fs/attr.c b/fs/attr.c
index df28035aa23e..0a7f9d67bb35 100644
--- a/fs/attr.c
+++ b/fs/attr.c
@@ -226,7 +226,7 @@ EXPORT_SYMBOL(setattr_copy);
  * the file open for write, as there can be no conflicting delegation in
  * that case.
  */
-int notify_change(struct dentry * dentry, struct iattr * attr, struct inode **delegated_inode)
+int notify_change2(struct vfsmount *mnt, struct dentry * dentry, struct iattr * attr, struct inode **delegated_inode)
 {
 	struct inode *inode = dentry->d_inode;
 	umode_t mode = inode->i_mode;
@@ -333,7 +333,9 @@ int notify_change(struct dentry * dentry, struct iattr * attr, struct inode **de
 	if (error)
 		return error;
 
-	if (inode->i_op->setattr)
+	if (mnt && inode->i_op->setattr2)
+		error = inode->i_op->setattr2(mnt, dentry, attr);
+	else if (inode->i_op->setattr)
 		error = inode->i_op->setattr(dentry, attr);
 	else
 		error = simple_setattr(dentry, attr);
@@ -346,4 +348,10 @@ int notify_change(struct dentry * dentry, struct iattr * attr, struct inode **de
 
 	return error;
 }
+EXPORT_SYMBOL(notify_change2);
+
+int notify_change(struct dentry * dentry, struct iattr * attr, struct inode **delegated_inode)
+{
+	return notify_change2(NULL, dentry, attr, delegated_inode);
+}
 EXPORT_SYMBOL(notify_change);
diff --git a/fs/coredump.c b/fs/coredump.c
index b1ea7dfbd149..a6b542bb4d85 100644
--- a/fs/coredump.c
+++ b/fs/coredump.c
@@ -775,7 +775,7 @@ void do_coredump(const kernel_siginfo_t *siginfo)
 			goto close_fail;
 		if (!(cprm.file->f_mode & FMODE_CAN_WRITE))
 			goto close_fail;
-		if (do_truncate(cprm.file->f_path.dentry, 0, 0, cprm.file))
+		if (do_truncate2(cprm.file->f_path.mnt, cprm.file->f_path.dentry, 0, 0, cprm.file))
 			goto close_fail;
 	}
 
diff --git a/fs/inode.c b/fs/inode.c
index 96d62d97694e..d3c34236ef99 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -1817,7 +1817,7 @@ int dentry_needs_remove_privs(struct dentry *dentry)
 	return mask;
 }
 
-static int __remove_privs(struct dentry *dentry, int kill)
+static int __remove_privs(struct vfsmount *mnt, struct dentry *dentry, int kill)
 {
 	struct iattr newattrs;
 
@@ -1826,7 +1826,7 @@ static int __remove_privs(struct dentry *dentry, int kill)
 	 * Note we call this on write, so notify_change will not
 	 * encounter any conflicting delegations:
 	 */
-	return notify_change(dentry, &newattrs, NULL);
+	return notify_change2(mnt, dentry, &newattrs, NULL);
 }
 
 /*
@@ -1853,7 +1853,7 @@ int file_remove_privs(struct file *file)
 	if (kill < 0)
 		return kill;
 	if (kill)
-		error = __remove_privs(dentry, kill);
+		error = __remove_privs(file->f_path.mnt, dentry, kill);
 	if (!error)
 		inode_has_no_xattr(inode);
 
diff --git a/fs/namei.c b/fs/namei.c
index 671c3c1a3425..8a77269e644f 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2995,7 +2995,7 @@ static int handle_truncate(struct file *filp)
 	if (!error)
 		error = security_path_truncate(path);
 	if (!error) {
-		error = do_truncate(path->dentry, 0,
+		error = do_truncate2(path->mnt, path->dentry, 0,
 				    ATTR_MTIME|ATTR_CTIME|ATTR_OPEN,
 				    filp);
 	}
diff --git a/fs/open.c b/fs/open.c
index b62f5c0923a8..a189284464a0 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -35,8 +35,8 @@
 
 #include "internal.h"
 
-int do_truncate(struct dentry *dentry, loff_t length, unsigned int time_attrs,
-	struct file *filp)
+int do_truncate2(struct vfsmount *mnt, struct dentry *dentry, loff_t length,
+		unsigned int time_attrs, struct file *filp)
 {
 	int ret;
 	struct iattr newattrs;
@@ -61,17 +61,24 @@ int do_truncate(struct dentry *dentry, loff_t length, unsigned int time_attrs,
 
 	inode_lock(dentry->d_inode);
 	/* Note any delegations or leases have already been broken: */
-	ret = notify_change(dentry, &newattrs, NULL);
+	ret = notify_change2(mnt, dentry, &newattrs, NULL);
 	inode_unlock(dentry->d_inode);
 	return ret;
 }
+int do_truncate(struct dentry *dentry, loff_t length, unsigned int time_attrs,
+	struct file *filp)
+{
+	return do_truncate2(NULL, dentry, length, time_attrs, filp);
+}
 
 long vfs_truncate(const struct path *path, loff_t length)
 {
 	struct inode *inode;
+	struct vfsmount *mnt;
 	long error;
 
 	inode = path->dentry->d_inode;
+	mnt = path->mnt;
 
 	/* For directories it's -EISDIR, for other non-regulars - -EINVAL */
 	if (S_ISDIR(inode->i_mode))
@@ -107,7 +114,7 @@ long vfs_truncate(const struct path *path, loff_t length)
 	if (!error)
 		error = security_path_truncate(path);
 	if (!error)
-		error = do_truncate(path->dentry, length, 0, NULL);
+		error = do_truncate2(mnt, path->dentry, length, 0, NULL);
 
 put_write_and_out:
 	put_write_access(inode);
@@ -156,6 +163,7 @@ long do_sys_ftruncate(unsigned int fd, loff_t length, int small)
 {
 	struct inode *inode;
 	struct dentry *dentry;
+	struct vfsmount *mnt;
 	struct fd f;
 	int error;
 
@@ -172,6 +180,7 @@ long do_sys_ftruncate(unsigned int fd, loff_t length, int small)
 		small = 0;
 
 	dentry = f.file->f_path.dentry;
+	mnt = f.file->f_path.mnt;
 	inode = dentry->d_inode;
 	error = -EINVAL;
 	if (!S_ISREG(inode->i_mode) || !(f.file->f_mode & FMODE_WRITE))
@@ -192,7 +201,7 @@ long do_sys_ftruncate(unsigned int fd, loff_t length, int small)
 	if (!error)
 		error = security_path_truncate(&f.file->f_path);
 	if (!error)
-		error = do_truncate(dentry, length, ATTR_MTIME|ATTR_CTIME, f.file);
+		error = do_truncate2(mnt, dentry, length, ATTR_MTIME|ATTR_CTIME, f.file);
 	sb_end_write(inode->i_sb);
 out_putf:
 	fdput(f);
@@ -558,7 +567,7 @@ static int chmod_common(const struct path *path, umode_t mode)
 		goto out_unlock;
 	newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO);
 	newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
-	error = notify_change(path->dentry, &newattrs, &delegated_inode);
+	error = notify_change2(path->mnt, path->dentry, &newattrs, &delegated_inode);
 out_unlock:
 	inode_unlock(inode);
 	if (delegated_inode) {
@@ -649,7 +658,7 @@ static int chown_common(const struct path *path, uid_t user, gid_t group)
 	inode_lock(inode);
 	error = security_path_chown(path, uid, gid);
 	if (!error)
-		error = notify_change(path->dentry, &newattrs, &delegated_inode);
+		error = notify_change2(path->mnt, path->dentry, &newattrs, &delegated_inode);
 	inode_unlock(inode);
 	if (delegated_inode) {
 		error = break_deleg_wait(&delegated_inode);
diff --git a/fs/utimes.c b/fs/utimes.c
index 1ba3f7883870..93a3a58a4f6d 100644
--- a/fs/utimes.c
+++ b/fs/utimes.c
@@ -57,7 +57,7 @@ static int utimes_common(const struct path *path, struct timespec64 *times)
 	}
 retry_deleg:
 	inode_lock(inode);
-	error = notify_change(path->dentry, &newattrs, &delegated_inode);
+	error = notify_change2(path->mnt, path->dentry, &newattrs, &delegated_inode);
 	inode_unlock(inode);
 	if (delegated_inode) {
 		error = break_deleg_wait(&delegated_inode);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 0b4d8fc79e0f..ae6dfb6a20c6 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1878,7 +1878,8 @@ struct inode_operations {
 	int (*rename) (struct inode *, struct dentry *,
 			struct inode *, struct dentry *, unsigned int);
 	int (*setattr) (struct dentry *, struct iattr *);
-	int (*getattr) (const struct path *, struct kstat *, u32, unsigned int);
+	int (*setattr2) (struct vfsmount *, struct dentry *, struct iattr *);
+        int (*getattr) (const struct path *, struct kstat *, u32, unsigned int);
 	ssize_t (*listxattr) (struct dentry *, char *, size_t);
 	int (*fiemap)(struct inode *, struct fiemap_extent_info *, u64 start,
 		      u64 len);
@@ -2526,6 +2527,8 @@ static_assert(offsetof(struct filename, iname) % sizeof(long) == 0);
 extern long vfs_truncate(const struct path *, loff_t);
 extern int do_truncate(struct dentry *, loff_t start, unsigned int time_attrs,
 		       struct file *filp);
+extern int do_truncate2(struct vfsmount *, struct dentry *, loff_t start,
+			unsigned int time_attrs, struct file *filp);
 extern int vfs_fallocate(struct file *file, int mode, loff_t offset,
 			loff_t len);
 extern long do_sys_open(int dfd, const char __user *filename, int flags,
@@ -2873,6 +2876,7 @@ extern void emergency_remount(void);
 extern sector_t bmap(struct inode *, sector_t);
 #endif
 extern int notify_change(struct dentry *, struct iattr *, struct inode **);
+extern int notify_change2(struct vfsmount *, struct dentry *, struct iattr *, struct inode **);
 extern int inode_permission(struct inode *, int);
 extern int generic_permission(struct inode *, int);
 extern int __check_sticky(struct inode *dir, struct inode *inode);