[PATCH 2/2] erofs: set blksize to on-disk blksize for fscache mode

[Jingbo Xu <jefflexu@linux.alibaba.com>]

Since fscache mode has supported PAGE_SIZE other than 4KB, remove the
constraint and set to on-disk blksize.

We need to initialize the fscache context for the bootstrap before
setting the initial blksize as it will also update anonymous inode's
i_blkbits for the bootstrap.

Signed-off-by: Jingbo Xu <jefflexu@linux.alibaba.com>
---
 fs/erofs/super.c | 38 ++++++++++++++++++++------------------
 1 file changed, 20 insertions(+), 18 deletions(-)

diff --git a/fs/erofs/super.c b/fs/erofs/super.c
index 89011a4ed274..130e0f6db3c7 100644
--- a/fs/erofs/super.c
+++ b/fs/erofs/super.c
@@ -709,6 +709,17 @@ static int erofs_fc_fill_pseudo_super(struct super_block *sb, struct fs_context
 	return simple_fill_super(sb, EROFS_SUPER_MAGIC, &empty_descr);
 }
 
+static bool erofs_set_block_size(struct super_block *sb, unsigned int blkszbits)
+{
+	if (!erofs_is_fscache_mode(sb))
+		return sb_set_blocksize(sb, 1 << blkszbits);
+
+	sb->s_blocksize = 1 << blkszbits;
+	sb->s_blocksize_bits = blkszbits;
+	EROFS_SB(sb)->s_fscache->inode->i_blkbits = blkszbits;
+	return true;
+}
+
 static int erofs_fc_fill_super(struct super_block *sb, struct fs_context *fc)
 {
 	struct inode *inode;
@@ -734,11 +745,7 @@ static int erofs_fc_fill_super(struct super_block *sb, struct fs_context *fc)
 	sbi->domain_id = ctx->domain_id;
 	ctx->domain_id = NULL;
 
-	sbi->blkszbits = PAGE_SHIFT;
 	if (erofs_is_fscache_mode(sb)) {
-		sb->s_blocksize = PAGE_SIZE;
-		sb->s_blocksize_bits = PAGE_SHIFT;
-
 		err = erofs_fscache_register_fs(sb);
 		if (err)
 			return err;
@@ -747,29 +754,24 @@ static int erofs_fc_fill_super(struct super_block *sb, struct fs_context *fc)
 		if (err)
 			return err;
 	} else {
-		if (!sb_set_blocksize(sb, PAGE_SIZE)) {
-			errorfc(fc, "failed to set initial blksize");
-			return -EINVAL;
-		}
-
 		sbi->dax_dev = fs_dax_get_by_bdev(sb->s_bdev,
 						  &sbi->dax_part_off,
 						  NULL, NULL);
 	}
 
+	if (!erofs_set_block_size(sb, PAGE_SHIFT)) {
+		errorfc(fc, "failed to set initial blksize");
+		return -EINVAL;
+	}
+
 	err = erofs_read_superblock(sb);
 	if (err)
 		return err;
 
-	if (sb->s_blocksize_bits != sbi->blkszbits) {
-		if (erofs_is_fscache_mode(sb)) {
-			errorfc(fc, "unsupported blksize for fscache mode");
-			return -EINVAL;
-		}
-		if (!sb_set_blocksize(sb, 1 << sbi->blkszbits)) {
-			errorfc(fc, "failed to set erofs blksize");
-			return -EINVAL;
-		}
+	if (sb->s_blocksize_bits != sbi->blkszbits &&
+	    !erofs_set_block_size(sb, sbi->blkszbits)) {
+		errorfc(fc, "failed to set erofs blksize");
+		return -EINVAL;
 	}
 
 	if (test_opt(&sbi->opt, DAX_ALWAYS)) {
-- 
2.19.1.6.gb485710b