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, 7 deletions

diff --git a/fs/erofs/namei.c b/fs/erofs/namei.c
index 966eabc61c13..f091e9a0f0a1 100644
--- a/fs/erofs/namei.c
+++ b/fs/erofs/namei.c
@@ -89,7 +89,8 @@ static struct erofs_dirent *find_target_dirent(struct erofs_qstr *name,
 static void *erofs_find_target_block(struct erofs_buf *target,
 		struct inode *dir, struct erofs_qstr *name, int *_ndirents)
 {
-	int head = 0, back = DIV_ROUND_UP(dir->i_size, EROFS_BLKSIZ) - 1;
+	unsigned int bsz = i_blocksize(dir);
+	int head = 0, back = erofs_iblks(dir) - 1;
 	unsigned int startprfx = 0, endprfx = 0;
 	void *candidate = ERR_PTR(-ENOENT);
 
@@ -100,8 +101,7 @@ static void *erofs_find_target_block(struct erofs_buf *target,
 
 		de = erofs_bread(&buf, dir, mid, EROFS_KMAP);
 		if (!IS_ERR(de)) {
-			const int nameoff = nameoff_from_disk(de->nameoff,
-							      EROFS_BLKSIZ);
+			const int nameoff = nameoff_from_disk(de->nameoff, bsz);
 			const int ndirents = nameoff / sizeof(*de);
 			int diff;
 			unsigned int matched;
@@ -121,11 +121,10 @@ static void *erofs_find_target_block(struct erofs_buf *target,
 
 			dname.name = (u8 *)de + nameoff;
 			if (ndirents == 1)
-				dname.end = (u8 *)de + EROFS_BLKSIZ;
+				dname.end = (u8 *)de + bsz;
 			else
 				dname.end = (u8 *)de +
-					nameoff_from_disk(de[1].nameoff,
-							  EROFS_BLKSIZ);
+					nameoff_from_disk(de[1].nameoff, bsz);
 
 			/* string comparison without already matched prefix */
 			diff = erofs_dirnamecmp(name, &dname, &matched);
@@ -178,7 +177,8 @@ int erofs_namei(struct inode *dir, const struct qstr *name, erofs_nid_t *nid,
 		return PTR_ERR(de);
 
 	if (ndirents)
-		de = find_target_dirent(&qn, (u8 *)de, EROFS_BLKSIZ, ndirents);
+		de = find_target_dirent(&qn, (u8 *)de, i_blocksize(dir),
+					ndirents);
 
 	if (!IS_ERR(de)) {
 		*nid = le64_to_cpu(de->nid);