github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-07-27 09:36:22 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity Graph

exfat: add data_start_bytes and exfat_cluster_to_phys_bytes() helper

Browse Source 
This caches the data area start offset in bytes (data_start_bytes)
and introduces a helper function exfat_cluster_to_phys_bytes() to compute
the physical byte position of a given cluster.

Acked-by: Christoph Hellwig <hch@lst.de>
Acked-by: "Darrick J. Wong" <djwong@kernel.org>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
This commit is contained in:
Namjae Jeon 2026-05-06 10:52:27 +09:00
parent 286ae36887
commit 3b9450beeb
2 changed files with 9 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
fs/exfat/exfat_fs.h
View File

@ -227,6 +227,7 @@ struct exfat_sb_info {
unsigned long long FAT1_start_sector; /* FAT1 start sector */
unsigned long long FAT2_start_sector; /* FAT2 start sector */
unsigned long long data_start_sector; /* data area start sector */
unsigned long long data_start_bytes;
unsigned int num_FAT_sectors; /* num of FAT sectors */
unsigned int root_dir; /* root dir cluster */
unsigned int dentries_per_clu; /* num of dentries per cluster */
@ -400,6 +401,13 @@ static inline loff_t exfat_ondisk_size(const struct inode *inode)
return ((loff_t)inode->i_blocks) << 9;
}
static inline loff_t exfat_cluster_to_phys_bytes(struct exfat_sb_info *sbi,
unsigned int clus)
{
return ((loff_t)(clus - EXFAT_RESERVED_CLUSTERS) << sbi->cluster_size_bits) +
sbi->data_start_bytes;
}
/*
* helpers for cluster size to byte conversion.
*/

1
fs/exfat/super.c
View File

@ -499,6 +499,7 @@ static int exfat_read_boot_sector(struct super_block *sb)
if (p_boot->num_fats == 2)
sbi->FAT2_start_sector += sbi->num_FAT_sectors;
sbi->data_start_sector = le32_to_cpu(p_boot->clu_offset);
sbi->data_start_bytes = sbi->data_start_sector << p_boot->sect_size_bits;
sbi->num_sectors = le64_to_cpu(p_boot->vol_length);
/* because the cluster index starts with 2 */
sbi->num_clusters = le32_to_cpu(p_boot->clu_count) +