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.

Change-Id: I19959038309284448f1b7f232d579674ef546385
Signed-off-by: Daniel Rosenberg <drosen@google.com>

7 files changed, 34 insertions, 15 deletions

diff --git a/fs/attr.c b/fs/attr.c
index 6530ced19697..34926834cd49 100644
--- a/fs/attr.c
+++ b/fs/attr.c
@@ -187,7 +187,7 @@ 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;
@@ -262,7 +262,9 @@ 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);
@@ -275,4 +277,10 @@ 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 1777331eee76..84d251b582e9 100644
--- a/fs/coredump.c
+++ b/fs/coredump.c
@@ -695,7 +695,7 @@ void do_coredump(const 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 1be5f9003eb3..aa3cf5a1b819 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -1715,7 +1715,7 @@ int dentry_needs_remove_privs(struct dentry *dentry)
 }
 EXPORT_SYMBOL(dentry_needs_remove_privs);
 
-static int __remove_privs(struct dentry *dentry, int kill)
+static int __remove_privs(struct vfsmount *mnt, struct dentry *dentry, int kill)
 {
 	struct iattr newattrs;
 
@@ -1724,7 +1724,7 @@ 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);
 }
 
 /*
@@ -1746,7 +1746,7 @@ 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 82c7ec6532d5..0230bc59f344 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2760,7 +2760,7 @@ 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 1786467725b9..08406e19e2cf 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -34,8 +34,8 @@
 
 #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;
@@ -60,10 +60,15 @@ int do_truncate(struct dentry *dentry, loff_t length, unsigned int time_attrs,
 
 	mutex_lock(&dentry->d_inode->i_mutex);
 	/* Note any delegations or leases have already been broken: */
-	ret = notify_change(dentry, &newattrs, NULL);
+	ret = notify_change2(mnt, dentry, &newattrs, NULL);
 	mutex_unlock(&dentry->d_inode->i_mutex);
 	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(struct path *path, loff_t length)
 {
@@ -108,7 +113,7 @@ long vfs_truncate(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);
@@ -157,6 +162,7 @@ static 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;
 
@@ -173,6 +179,7 @@ static 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 +199,7 @@ static 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);
@@ -522,7 +529,7 @@ retry_deleg:
 		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:
 	mutex_unlock(&inode->i_mutex);
 	if (delegated_inode) {
@@ -602,7 +609,7 @@ retry_deleg:
 	mutex_lock(&inode->i_mutex);
 	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);
 	mutex_unlock(&inode->i_mutex);
 	if (delegated_inode) {
 		error = break_deleg_wait(&delegated_inode);
diff --git a/fs/utimes.c b/fs/utimes.c
index c3c663dbf083..dfb457546c60 100644
--- a/fs/utimes.c
+++ b/fs/utimes.c
@@ -104,7 +104,7 @@ static int utimes_common(struct path *path, struct timespec *times)
 	}
 retry_deleg:
 	mutex_lock(&inode->i_mutex);
-	error = notify_change(path->dentry, &newattrs, &delegated_inode);
+	error = notify_change2(path->mnt, path->dentry, &newattrs, &delegated_inode);
 	mutex_unlock(&inode->i_mutex);
 	if (delegated_inode) {
 		error = break_deleg_wait(&delegated_inode);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index b5a863580120..31bf8e1e58ff 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1661,6 +1661,7 @@ struct inode_operations {
 	int (*rename2) (struct inode *, struct dentry *,
 			struct inode *, struct dentry *, unsigned int);
 	int (*setattr) (struct dentry *, struct iattr *);
+	int (*setattr2) (struct vfsmount *, struct dentry *, struct iattr *);
 	int (*getattr) (struct vfsmount *mnt, struct dentry *, struct kstat *);
 	int (*setxattr) (struct dentry *, const char *,const void *,size_t,int);
 	ssize_t (*getxattr) (struct dentry *, const char *, void *, size_t);
@@ -2226,6 +2227,8 @@ struct filename {
 extern long vfs_truncate(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,
@@ -2450,6 +2453,7 @@ 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 inode_permission2(struct vfsmount *, struct inode *, int);
 extern int __inode_permission(struct inode *, int);