fuse: fix stat call on 32 bit platforms

Now we store attr->ino at inode->i_ino, return attr->ino at the
first time and then return inode->i_ino if the attribute timeout
isn't expired. That's wrong on 32 bit platforms because attr->ino
is 64 bit and inode->i_ino is 32 bit in this case.

Fix this by saving 64 bit ino in fuse_inode structure and returning
it every time we call getattr. Also squash attr->ino into inode->i_ino
explicitly.

Signed-off-by: Pavel Shilovsky <[email protected]>
Signed-off-by: Miklos Szeredi <[email protected]>

Author: piastry

fs/fuse/dir.c

@@ -863,6 +863,7 @@ int fuse_update_attributes(struct inode *inode, struct kstat *stat,
 		if (stat) {
 			generic_fillattr(inode, stat);
 			stat->mode = fi->orig_i_mode;
+			stat->ino = fi->orig_ino;
 		}
 	}
 

fs/fuse/fuse_i.h

@@ -82,6 +82,9 @@ struct fuse_inode {
 	    preserve the original mode */
 	umode_t orig_i_mode;
 
+	/** 64 bit inode number */
+	u64 orig_ino;
+
 	/** Version of last attribute change */
 	u64 attr_version;
 

fs/fuse/inode.c

@@ -91,6 +91,7 @@ static struct inode *fuse_alloc_inode(struct super_block *sb)
 	fi->nlookup = 0;
 	fi->attr_version = 0;
 	fi->writectr = 0;
+	fi->orig_ino = 0;
 	INIT_LIST_HEAD(&fi->write_files);
 	INIT_LIST_HEAD(&fi->queued_writes);
 	INIT_LIST_HEAD(&fi->writepages);
@@ -139,6 +140,18 @@ static int fuse_remount_fs(struct super_block *sb, int *flags, char *data)
 	return 0;
 }
 
+/*
+ * ino_t is 32-bits on 32-bit arch. We have to squash the 64-bit value down
+ * so that it will fit.
+ */
+static ino_t fuse_squash_ino(u64 ino64)
+{
+	ino_t ino = (ino_t) ino64;
+	if (sizeof(ino_t) < sizeof(u64))
+		ino ^= ino64 >> (sizeof(u64) - sizeof(ino_t)) * 8;
+	return ino;
+}
+
 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
 				   u64 attr_valid)
 {
@@ -148,7 +161,7 @@ void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
 	fi->attr_version = ++fc->attr_version;
 	fi->i_time = attr_valid;
 
-	inode->i_ino     = attr->ino;
+	inode->i_ino     = fuse_squash_ino(attr->ino);
 	inode->i_mode    = (inode->i_mode & S_IFMT) | (attr->mode & 07777);
 	set_nlink(inode, attr->nlink);
 	inode->i_uid     = attr->uid;
@@ -174,6 +187,8 @@ void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
 	fi->orig_i_mode = inode->i_mode;
 	if (!(fc->flags & FUSE_DEFAULT_PERMISSIONS))
 		inode->i_mode &= ~S_ISVTX;
+
+	fi->orig_ino = attr->ino;
 }
 
 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,