Namjae Jeon <linkinjeon@xxxxxxxxx> writes:
> diff --git a/fs/fat/cache.c b/fs/fat/cache.c
> index c56bd7e..7777822 100644
> --- a/fs/fat/cache.c
> +++ b/fs/fat/cache.c
> @@ -312,6 +312,7 @@ int fat_bmap(struct inode *inode, sector_t sector, sector_t *phys,
> const unsigned char blocksize_bits = sb->s_blocksize_bits;
> sector_t last_block;
> int cluster, offset;
> + loff_t i_size = i_size_read(inode);
>
> *phys = 0;
> *mapped_blocks = 0;
> @@ -323,10 +324,20 @@ int fat_bmap(struct inode *inode, sector_t sector, sector_t *phys,
> return 0;
> }
>
> - last_block = (i_size_read(inode) + (blocksize - 1)) >> blocksize_bits;
> + last_block = (i_size + (blocksize - 1)) >> blocksize_bits;
> if (sector >= last_block) {
> - if (!create)
> + if (!create) {
> + /*
> + * to map cluster in case of read request
> + * for a block in fallocated region
> + */
> + if (MSDOS_I(inode)->i_disksize >
> + round_up(i_size, sb->s_blocksize)) {
> + goto out_map_cluster;
> + }
Said on another reply though, we will have to add new flag for
this. Because normal read get_block() operation should not return
mapping beyond ->i_size.
> /* fat_get_cluster() assumes the requested blocknr isn't truncated. */
> - down_read(&MSDOS_I(mapping->host)->truncate_lock);
> + mutex_lock(&mapping->host->i_mutex);
> blocknr = generic_block_bmap(mapping, block, fat_get_block);
> - up_read(&MSDOS_I(mapping->host)->truncate_lock);
> + mutex_unlock(&mapping->host->i_mutex);
>
> return blocknr;
> }
->i_mutex doesn't work for swapfile.
--
OGAWA Hirofumi <hirofumi@xxxxxxxxxxxxxxxxxx>
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