erofs: avoid hardcoded blocksize for subpage block support

As the first step of converting hardcoded blocksize to that specified in
on-disk superblock, convert all call sites of hardcoded blocksize to
sb->s_blocksize except for:

1) use sbi->blkszbits instead of sb->s_blocksize in
erofs_superblock_csum_verify() since sb->s_blocksize has not been
updated with the on-disk blocksize yet when the function is called.

2) use inode->i_blkbits instead of sb->s_blocksize in erofs_bread(),
since the inode operated on may be an anonymous inode in fscache mode.
Currently the anonymous inode is allocated from an anonymous mount
maintained in erofs, while in the near future we may allocate anonymous
inodes from a generic API directly and thus have no access to the
anonymous inode's i_sb.  Thus we keep the block size in i_blkbits for
anonymous inodes in fscache mode.

Be noted that this patch only gets rid of the hardcoded blocksize, in
preparation for actually setting the on-disk block size in the following
patch.  The hard limit of constraining the block size to PAGE_SIZE still
exists until the next patch.

Signed-off-by: Jingbo Xu <jefflexu@linux.alibaba.com>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Reviewed-by: Yue Hu <huyue2@coolpad.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Link: https://lore.kernel.org/r/20230313135309.75269-2-jefflexu@linux.alibaba.com
[ Gao Xiang: fold a patch to fix incorrect truncated offsets. ]
Link: https://lore.kernel.org/r/20230413035734.15457-1-zhujia.zj@bytedance.com
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>

1 files changed, 7 insertions, 13 deletions

diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index 1db018f8c2e8..66ff0513866f 100644
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -147,8 +147,8 @@ struct erofs_sb_info {
 #endif
 	u16 device_id_mask;	/* valid bits of device id to be used */
 
-	/* inode slot unit size in bit shift */
-	unsigned char islotbits;
+	unsigned char islotbits;	/* inode slot unit size in bit shift */
+	unsigned char blkszbits;
 
 	u32 sb_size;			/* total superblock size */
 	u32 build_time_nsec;
@@ -242,13 +242,6 @@ static inline int erofs_wait_on_workgroup_freezed(struct erofs_workgroup *grp)
 
 /* we strictly follow PAGE_SIZE and no buffer head yet */
 #define LOG_BLOCK_SIZE		PAGE_SHIFT
-
-#undef LOG_SECTORS_PER_BLOCK
-#define LOG_SECTORS_PER_BLOCK	(PAGE_SHIFT - 9)
-
-#undef SECTORS_PER_BLOCK
-#define SECTORS_PER_BLOCK	(1 << SECTORS_PER_BLOCK)
-
 #define EROFS_BLKSIZ		(1 << LOG_BLOCK_SIZE)
 
 #if (EROFS_BLKSIZ % 4096 || !EROFS_BLKSIZ)
@@ -269,9 +262,10 @@ struct erofs_buf {
 
 #define ROOT_NID(sb)		((sb)->root_nid)
 
-#define erofs_blknr(addr)       ((addr) / EROFS_BLKSIZ)
-#define erofs_blkoff(addr)      ((addr) % EROFS_BLKSIZ)
-#define blknr_to_addr(nr)       ((erofs_off_t)(nr) * EROFS_BLKSIZ)
+#define erofs_blknr(sb, addr)	((addr) >> (sb)->s_blocksize_bits)
+#define erofs_blkoff(sb, addr)	((addr) & ((sb)->s_blocksize - 1))
+#define erofs_pos(sb, blk)	((erofs_off_t)(blk) << (sb)->s_blocksize_bits)
+#define erofs_iblks(i)	(round_up((i)->i_size, i_blocksize(i)) >> (i)->i_blkbits)
 
 #define EROFS_FEATURE_FUNCS(name, compat, feature) \
 static inline bool erofs_sb_has_##name(struct erofs_sb_info *sbi) \
@@ -343,7 +337,7 @@ static inline erofs_off_t erofs_iloc(struct inode *inode)
 {
 	struct erofs_sb_info *sbi = EROFS_I_SB(inode);
 
-	return blknr_to_addr(sbi->meta_blkaddr) +
+	return erofs_pos(inode->i_sb, sbi->meta_blkaddr) +
 		(EROFS_I(inode)->nid << sbi->islotbits);
 }