[PATCH v3] fuse: fix stat call on 32 bit platforms

[Pavel Shilovsky <piastry@xxxxxxxxxxx>]

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 <piastry@xxxxxxxxxxx>
---
 fs/fuse/dir.c    |    3 ++-
 fs/fuse/fuse_i.h |    3 +++
 fs/fuse/inode.c  |   17 ++++++++++++++++-
 3 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index df5ac04..b260c16 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -776,7 +776,7 @@ static void fuse_fillattr(struct inode *inode, struct fuse_attr *attr,
 			  struct kstat *stat)
 {
 	stat->dev = inode->i_sb->s_dev;
-	stat->ino = attr->ino;
+	stat->ino = get_fuse_inode(inode)->ino;
 	stat->mode = (inode->i_mode & S_IFMT) | (attr->mode & 07777);
 	stat->nlink = attr->nlink;
 	stat->uid = attr->uid;
@@ -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->ino;
 		}
 	}
 
diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index 572cefc..e2fefdf 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -100,6 +100,9 @@ struct fuse_inode {
 
 	/** List of writepage requestst (pending or sent) */
 	struct list_head writepages;
+
+	/** 64 bit inode number */
+	u64 ino;
 };
 
 struct fuse_conn;
diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index 26783eb..c5a5c4c 100644
--- a/fs/fuse/inode.c
+++ b/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->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_uniqueid_to_ino(u64 uniqueid)
+{
+	ino_t ino = (ino_t) uniqueid;
+	if (sizeof(ino_t) < sizeof(u64))
+		ino ^= uniqueid >> (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_uniqueid_to_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->ino = attr->ino;
 }
 
 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
-- 
1.7.1

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