ext4: factor out ext4_get_maxbytes()

commit dbe27f0 upstream.

There are several locations that get the correct maxbytes value based on
the inode's block type. It would be beneficial to extract a common
helper function to make the code more clear.

Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Baokun Li <libaokun1@huawei.com>
Link: https://patch.msgid.link/20250506012009.3896990-3-yi.zhang@huaweicloud.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit 68cea04f1fb2ead5e10e1be8be98cb1cb24334ba)

Author: zhangyi089

fs/ext4/ext4.h

@@ -3351,6 +3351,13 @@ static inline unsigned int ext4_flex_bg_size(struct ext4_sb_info *sbi)
 	return 1 << sbi->s_log_groups_per_flex;
 }
 
+static inline loff_t ext4_get_maxbytes(struct inode *inode)
+{
+	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
+		return inode->i_sb->s_maxbytes;
+	return EXT4_SB(inode->i_sb)->s_bitmap_maxbytes;
+}
+
 #define ext4_std_error(sb, errno)				\
 do {								\
 	if ((errno))						\

fs/ext4/extents.c

@@ -4970,12 +4970,7 @@ static const struct iomap_ops ext4_iomap_xattr_ops = {
 
 static int ext4_fiemap_check_ranges(struct inode *inode, u64 start, u64 *len)
 {
-	u64 maxbytes;
-
-	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
-		maxbytes = inode->i_sb->s_maxbytes;
-	else
-		maxbytes = EXT4_SB(inode->i_sb)->s_bitmap_maxbytes;
+	u64 maxbytes = ext4_get_maxbytes(inode);
 
 	if (*len == 0)
 		return -EINVAL;

fs/ext4/file.c

@@ -898,12 +898,7 @@ static int ext4_file_open(struct inode *inode, struct file *filp)
 loff_t ext4_llseek(struct file *file, loff_t offset, int whence)
 {
 	struct inode *inode = file->f_mapping->host;
-	loff_t maxbytes;
-
-	if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
-		maxbytes = EXT4_SB(inode->i_sb)->s_bitmap_maxbytes;
-	else
-		maxbytes = inode->i_sb->s_maxbytes;
+	loff_t maxbytes = ext4_get_maxbytes(inode);
 
 	switch (whence) {
 	default: