[PATCH RFC 8/8] fs: erofs: add unaligned read range handling

[Qu Wenruo]

I'm not an expert on erofs, but my quick glance didn't expose any
special handling on unaligned range, thus I think the U-boot erofs
driver doesn't really support unaligned read range.

This patch will add erofs_get_blocksize() so erofs can benefit from the
generic unaligned read support.

Cc: Huang Jianan <jnhuang95 at gmail.com>
Cc: linux-erofs at lists.ozlabs.org
Signed-off-by: Qu Wenruo <wqu at suse.com>
---
 fs/erofs/internal.h | 1 +
 fs/erofs/super.c    | 6 ++++++
 fs/fs.c             | 2 +-
 include/erofs.h     | 1 +
 4 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index 4af7c91560cc..d368a6481bf1 100644
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -83,6 +83,7 @@ struct erofs_sb_info {
 	u16 available_compr_algs;
 	u16 lz4_max_distance;
 	u32 checksum;
+	u32 blocksize;
 	u16 extra_devices;
 	union {
 		u16 devt_slotoff;		/* used for mkfs */
diff --git a/fs/erofs/super.c b/fs/erofs/super.c
index 4cca322b9ead..df01d2e719a7 100644
--- a/fs/erofs/super.c
+++ b/fs/erofs/super.c
@@ -99,7 +99,13 @@ int erofs_read_superblock(void)
 
 	sbi.build_time = le64_to_cpu(dsb->build_time);
 	sbi.build_time_nsec = le32_to_cpu(dsb->build_time_nsec);
+	sbi.blocksize = 1 << blkszbits;
 
 	memcpy(&sbi.uuid, dsb->uuid, sizeof(dsb->uuid));
 	return erofs_init_devices(&sbi, dsb);
 }
+
+int erofs_get_blocksize(const char *filename)
+{
+	return sbi.blocksize;
+}
diff --git a/fs/fs.c b/fs/fs.c
index 41943e3a95db..0ef5fbdda5d6 100644
--- a/fs/fs.c
+++ b/fs/fs.c
@@ -366,7 +366,7 @@ static struct fstype_info fstypes[] = {
 		.readdir = erofs_readdir,
 		.ls = fs_ls_generic,
 		.read = erofs_read,
-		.get_blocksize = fs_get_blocksize_unsupported,
+		.get_blocksize = erofs_get_blocksize,
 		.size = erofs_size,
 		.close = erofs_close,
 		.closedir = erofs_closedir,
diff --git a/include/erofs.h b/include/erofs.h
index 1fbe82bf72cb..18bd6807c538 100644
--- a/include/erofs.h
+++ b/include/erofs.h
@@ -10,6 +10,7 @@ int erofs_probe(struct blk_desc *fs_dev_desc,
 		struct disk_partition *fs_partition);
 int erofs_read(const char *filename, void *buf, loff_t offset,
 	       loff_t len, loff_t *actread);
+int erofs_get_blocksize(const char *filename);
 int erofs_size(const char *filename, loff_t *size);
 int erofs_exists(const char *filename);
 void erofs_close(void);
-- 
2.36.1