[PATCH v6 3/4] fat: permit to return phy block number by fibmap in fallocated region

[Namjae Jeon]

Make the fibmap call the return the proper physical block number for any
offset request in the fallocated range.

Signed-off-by: Namjae Jeon <***@samsung.com>
Signed-off-by: Amit Sahrawat <***@samsung.com>
---
fs/fat/cache.c | 38 +++++++++++++++++++++++++-------------
fs/fat/fat.h | 3 +++
fs/fat/inode.c | 33 ++++++++++++++++++++++++++++++++-
3 files changed, 60 insertions(+), 14 deletions(-)

diff --git a/fs/fat/cache.c b/fs/fat/cache.c
index 91ad9e1..d3dd5ba 100644
--- a/fs/fat/cache.c
+++ b/fs/fat/cache.c
@@ -303,6 +303,29 @@ static int fat_bmap_cluster(struct inode *inode, int cluster)
return dclus;
}

+int fat_get_mapped_cluster(struct inode *inode, sector_t sector,
+ sector_t last_block,
+ unsigned long *mapped_blocks, sector_t *bmap)
+{
+ struct super_block *sb = inode->i_sb;
+ struct msdos_sb_info *sbi = MSDOS_SB(sb);
+ int cluster, offset;
+
+ cluster = sector >> (sbi->cluster_bits - sb->s_blocksize_bits);
+ offset = sector & (sbi->sec_per_clus - 1);
+ cluster = fat_bmap_cluster(inode, cluster);
+ if (cluster < 0)
+ return cluster;
+ else if (cluster) {
+ *bmap = fat_clus_to_blknr(sbi, cluster) + offset;
+ *mapped_blocks = sbi->sec_per_clus - offset;
+ if (*mapped_blocks > last_block - sector)
+ *mapped_blocks = last_block - sector;
+ }
+
+ return 0;
+}
+
int fat_bmap(struct inode *inode, sector_t sector, sector_t *phys,
unsigned long *mapped_blocks, int create)
{
@@ -311,7 +334,6 @@ int fat_bmap(struct inode *inode, sector_t sector, sector_t *phys,
const unsigned long blocksize = sb->s_blocksize;
const unsigned char blocksize_bits = sb->s_blocksize_bits;
sector_t last_block;
- int cluster, offset;

*phys = 0;
*mapped_blocks = 0;
@@ -338,16 +360,6 @@ int fat_bmap(struct inode *inode, sector_t sector, sector_t *phys,
return 0;
}

- cluster = sector >> (sbi->cluster_bits - sb->s_blocksize_bits);
- offset = sector & (sbi->sec_per_clus - 1);
- cluster = fat_bmap_cluster(inode, cluster);
- if (cluster < 0)
- return cluster;
- else if (cluster) {
- *phys = fat_clus_to_blknr(sbi, cluster) + offset;
- *mapped_blocks = sbi->sec_per_clus - offset;
- if (*mapped_blocks > last_block - sector)
- *mapped_blocks = last_block - sector;
- }
- return 0;
+ return fat_get_mapped_cluster(inode, sector, last_block, mapped_blocks,
+ phys);
}
diff --git a/fs/fat/fat.h b/fs/fat/fat.h
index 5ee0095..808b092 100644
--- a/fs/fat/fat.h
+++ b/fs/fat/fat.h
@@ -288,6 +288,9 @@ static inline void fatwchar_to16(__u8 *dst, const wchar_t *src, size_t len)
extern void fat_cache_inval_inode(struct inode *inode);
extern int fat_get_cluster(struct inode *inode, int cluster,
int *fclus, int *dclus);
+extern int fat_get_mapped_cluster(struct inode *inode, sector_t sector,
+ sector_t last_block,
+ unsigned long *mapped_blocks, sector_t *bmap);
extern int fat_bmap(struct inode *inode, sector_t sector, sector_t *phys,
unsigned long *mapped_blocks, int create);

diff --git a/fs/fat/inode.c b/fs/fat/inode.c
index 20e9fe5..3034e1b 100644
--- a/fs/fat/inode.c
+++ b/fs/fat/inode.c
@@ -287,13 +287,44 @@ static ssize_t fat_direct_IO(int rw, struct kiocb *iocb,
return ret;
}

+static int fat_get_block_bmap(struct inode *inode, sector_t iblock,
+ struct buffer_head *bh_result, int create)
+{
+ struct super_block *sb = inode->i_sb;
+ unsigned long max_blocks = bh_result->b_size >> inode->i_blkbits;
+ int err;
+ sector_t bmap, last_block;
+ unsigned long mapped_blocks;
+
+ BUG_ON(create != 0);
+
+ last_block = inode->i_blocks;
+
+ if (iblock >= last_block)
+ return 0;
+
+ err = fat_get_mapped_cluster(inode, iblock, last_block, &mapped_blocks,
+ &bmap);
+ if (err)
+ return err;
+
+ if (bmap) {
+ map_bh(bh_result, sb, bmap);
+ max_blocks = min(mapped_blocks, max_blocks);
+ }
+
+ bh_result->b_size = max_blocks << sb->s_blocksize_bits;
+
+ return 0;
+}
+
static sector_t _fat_bmap(struct address_space *mapping, sector_t block)
{
sector_t blocknr;

/* fat_get_cluster() assumes the requested blocknr isn't truncated. */
down_read(&MSDOS_I(mapping->host)->truncate_lock);
- blocknr = generic_block_bmap(mapping, block, fat_get_block);
+ blocknr = generic_block_bmap(mapping, block, fat_get_block_bmap);
up_read(&MSDOS_I(mapping->host)->truncate_lock);

return blocknr;

[OGAWA Hirofumi]

Post by Namjae Jeon
+static int fat_get_block_bmap(struct inode *inode, sector_t iblock,
+ struct buffer_head *bh_result, int create)
+{
+ struct super_block *sb = inode->i_sb;
+ unsigned long max_blocks = bh_result->b_size >> inode->i_blkbits;
+ int err;
+ sector_t bmap, last_block;
+ unsigned long mapped_blocks;
+
+ BUG_ON(create != 0);
+
+ last_block = inode->i_blocks;
+
+ if (iblock >= last_block)
+ return 0;

This one also different unit.