[PATCH RFC 7/8] fs: ubifs: rely on higher layer to do unaligned read

[Qu Wenruo <wqu@suse.com>]

Currently ubifs doesn't support unaligned read offset, thanks to the
recent _fs_read() work to handle unaligned read, we only need to
implement ubifs_get_blocksize() to take advantage of it.

Now ubifs can do unaligned read without any problem.

Signed-off-by: Qu Wenruo <wqu@suse.com>
---
 fs/fs.c               |  2 +-
 fs/ubifs/ubifs.c      | 13 ++++++++-----
 include/ubifs_uboot.h |  1 +
 3 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/fs/fs.c b/fs/fs.c
index 337d5711c28c..41943e3a95db 100644
--- a/fs/fs.c
+++ b/fs/fs.c
@@ -302,7 +302,7 @@ static struct fstype_info fstypes[] = {
 		.exists = ubifs_exists,
 		.size = ubifs_size,
 		.read = ubifs_read,
-		.get_blocksize = fs_get_blocksize_unsupported,
+		.get_blocksize = ubifs_get_blocksize,
 		.write = fs_write_unsupported,
 		.uuid = fs_uuid_unsupported,
 		.opendir = fs_opendir_unsupported,
diff --git a/fs/ubifs/ubifs.c b/fs/ubifs/ubifs.c
index d3026e310168..a8ab556dd376 100644
--- a/fs/ubifs/ubifs.c
+++ b/fs/ubifs/ubifs.c
@@ -846,11 +846,9 @@ int ubifs_read(const char *filename, void *buf, loff_t offset,
 
 	*actread = 0;
 
-	if (offset & (PAGE_SIZE - 1)) {
-		printf("ubifs: Error offset must be a multiple of %d\n",
-		       PAGE_SIZE);
-		return -1;
-	}
+	/* Higher layer should ensure it always pass page aligned range. */
+	assert(IS_ALIGNED(offset, PAGE_SIZE));
+	assert(IS_ALIGNED(size, PAGE_SIZE));
 
 	c->ubi = ubi_open_volume(c->vi.ubi_num, c->vi.vol_id, UBI_READONLY);
 	/* ubifs_findfile will resolve symlinks, so we know that we get
@@ -920,6 +918,11 @@ out:
 	return err;
 }
 
+int ubifs_get_blocksize(const char *filename)
+{
+	return PAGE_SIZE;
+}
+
 void ubifs_close(void)
 {
 }
diff --git a/include/ubifs_uboot.h b/include/ubifs_uboot.h
index b025779d59ff..bcd21715314a 100644
--- a/include/ubifs_uboot.h
+++ b/include/ubifs_uboot.h
@@ -29,6 +29,7 @@ int ubifs_exists(const char *filename);
 int ubifs_size(const char *filename, loff_t *size);
 int ubifs_read(const char *filename, void *buf, loff_t offset,
 	       loff_t size, loff_t *actread);
+int ubifs_get_blocksize(const char *filename);
 void ubifs_close(void);
 
 #endif /* __UBIFS_UBOOT_H__ */
-- 
2.36.1