[PATCH RFC 5/9] minix: add minix_inode_block() helper

[Christian Brauner <brauner@kernel.org>]

Move the lookup of the block that holds an inode out of
minix_V1_raw_inode() and minix_V2_raw_inode() into a helper.
minix_sync_inode_metadata() is going to use it to find the block
without reading it from disk.

No functional changes.

Cc: stable@vger.kernel.org # v7.3
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
---
 fs/minix/bitmap.c | 37 +++++++++++++++++++++++--------------
 fs/minix/minix.h  |  1 +
 2 files changed, 24 insertions(+), 14 deletions(-)

diff --git a/fs/minix/bitmap.c b/fs/minix/bitmap.c
index abec438330a7..deac05472bef 100644
--- a/fs/minix/bitmap.c
+++ b/fs/minix/bitmap.c
@@ -103,21 +103,35 @@ unsigned long minix_count_free_blocks(struct super_block *sb)
 		<< sbi->s_log_zone_size);
 }
 
-struct minix_inode *
-minix_V1_raw_inode(struct super_block *sb, ino_t ino, struct buffer_head **bh)
+/* Return the block that holds inode @ino or 0 if @ino is out of range. */
+int minix_inode_block(struct super_block *sb, ino_t ino)
 {
-	int block;
 	struct minix_sb_info *sbi = minix_sb(sb);
-	struct minix_inode *p;
+	int inodes_per_block;
 
 	if (!ino || ino > sbi->s_ninodes) {
 		printk("Bad inode number on dev %s: %ld is out of range\n",
 		       sb->s_id, (long)ino);
-		return NULL;
+		return 0;
 	}
+	if (sbi->s_version == MINIX_V1)
+		inodes_per_block = MINIX_INODES_PER_BLOCK;
+	else
+		inodes_per_block = sb->s_blocksize / sizeof(struct minix2_inode);
+	return 2 + sbi->s_imap_blocks + sbi->s_zmap_blocks +
+		 (ino - 1) / inodes_per_block;
+}
+
+struct minix_inode *
+minix_V1_raw_inode(struct super_block *sb, ino_t ino, struct buffer_head **bh)
+{
+	int block;
+	struct minix_inode *p;
+
+	block = minix_inode_block(sb, ino);
+	if (!block)
+		return NULL;
 	ino--;
-	block = 2 + sbi->s_imap_blocks + sbi->s_zmap_blocks +
-		 ino / MINIX_INODES_PER_BLOCK;
 	*bh = sb_bread(sb, block);
 	if (!*bh) {
 		printk("Unable to read inode block\n");
@@ -131,19 +145,14 @@ struct minix2_inode *
 minix_V2_raw_inode(struct super_block *sb, ino_t ino, struct buffer_head **bh)
 {
 	int block;
-	struct minix_sb_info *sbi = minix_sb(sb);
 	struct minix2_inode *p;
 	int minix2_inodes_per_block = sb->s_blocksize / sizeof(struct minix2_inode);
 
 	*bh = NULL;
-	if (!ino || ino > sbi->s_ninodes) {
-		printk("Bad inode number on dev %s: %ld is out of range\n",
-		       sb->s_id, (long)ino);
+	block = minix_inode_block(sb, ino);
+	if (!block)
 		return NULL;
-	}
 	ino--;
-	block = 2 + sbi->s_imap_blocks + sbi->s_zmap_blocks +
-		 ino / minix2_inodes_per_block;
 	*bh = sb_bread(sb, block);
 	if (!*bh) {
 		printk("Unable to read inode block\n");
diff --git a/fs/minix/minix.h b/fs/minix/minix.h
index db92cf9e0e1b..67d8e2a7dc06 100644
--- a/fs/minix/minix.h
+++ b/fs/minix/minix.h
@@ -47,6 +47,7 @@ void __minix_error_inode(struct inode *inode, const char *function,
 			 unsigned int line, const char *fmt, ...);
 
 struct inode *minix_iget(struct super_block *, unsigned long);
+int minix_inode_block(struct super_block *sb, ino_t ino);
 struct minix_inode *minix_V1_raw_inode(struct super_block *, ino_t, struct buffer_head **);
 struct minix2_inode *minix_V2_raw_inode(struct super_block *, ino_t, struct buffer_head **);
 struct inode *minix_new_inode(const struct inode *, umode_t);

-- 
2.53.0