This adds a helper function which classifies meta-data blocks managed under persistent object allocator of nilfs.
The persistent object allocator uses three types of blocks, a descriptor block, a bitmap block, and an entry block, on a single meta-data file. The helper function calculates this type from a given block offset of the metadata file. Signed-off-by: Ryusuke Konishi <[email protected]> --- fs/nilfs2/alloc.c | 35 +++++++++++++++++++++++++++++++++-- fs/nilfs2/alloc.h | 10 ++++++++++ 2 files changed, 43 insertions(+), 2 deletions(-) diff --git a/fs/nilfs2/alloc.c b/fs/nilfs2/alloc.c index eed4d7b..b2d17f7 100644 --- a/fs/nilfs2/alloc.c +++ b/fs/nilfs2/alloc.c @@ -172,8 +172,7 @@ nilfs_palloc_group_desc_add_entries(struct inode *inode, * @inode: inode of metadata file using this allocator * @nr: serial number of the entry (e.g. inode number) */ -static unsigned long -nilfs_palloc_entry_blkoff(const struct inode *inode, __u64 nr) +unsigned long nilfs_palloc_entry_blkoff(const struct inode *inode, __u64 nr) { unsigned long group, group_offset; @@ -331,6 +330,38 @@ void *nilfs_palloc_block_get_entry(const struct inode *inode, __u64 nr, } /** + * nilfs_palloc_block_type - classify type of a block + * @inode: inode of metadata file using this allocator + * @blkoff: offset of the block to be classified (in block) + * @entrynr: first entry number in the block [out] + */ +int nilfs_palloc_block_type(const struct inode *inode, __u64 blkoff, + __u64 *entrynr) +{ + struct nilfs_mdt_info *mi = NILFS_MDT(inode); + __u64 ngroups1 = blkoff; + unsigned long offset1, offset2, ngroups2; + int ret; + + offset1 = do_div(ngroups1, mi->mi_blocks_per_desc_block); + if (offset1 == 0) { + ret = NILFS_PALLOC_DESC_BLOCK; + } else { + ngroups2 = (offset1 - 1) / mi->mi_blocks_per_group; + offset2 = (offset1 - 1) % mi->mi_blocks_per_group; + if (offset2 == 0) { + ret = NILFS_PALLOC_BITMAP_BLOCK; + } else { + ret = NILFS_PALLOC_ENTRY_BLOCK; + *entrynr = (ngroups1 + ngroups2) * + nilfs_palloc_entries_per_group(inode) + + mi->mi_entries_per_block * (offset2 - 1); + } + } + return ret; +} + +/** * nilfs_palloc_find_available_slot - find available slot in a group * @inode: inode of metadata file using this allocator * @group: group number diff --git a/fs/nilfs2/alloc.h b/fs/nilfs2/alloc.h index f5fde36..bcd5749 100644 --- a/fs/nilfs2/alloc.h +++ b/fs/nilfs2/alloc.h @@ -43,10 +43,20 @@ nilfs_palloc_entries_per_group(const struct inode *inode) } int nilfs_palloc_init_blockgroup(struct inode *, unsigned); +unsigned long nilfs_palloc_entry_blkoff(const struct inode *inode, __u64 nr); int nilfs_palloc_get_entry_block(struct inode *, __u64, int, struct buffer_head **); void *nilfs_palloc_block_get_entry(const struct inode *, __u64, const struct buffer_head *, void *); +int nilfs_palloc_block_type(const struct inode *inode, __u64 blkoff, + __u64 *entrynr); + +/* block types */ +enum { + NILFS_PALLOC_DESC_BLOCK, /* descriptor block */ + NILFS_PALLOC_BITMAP_BLOCK, /* bitmap block */ + NILFS_PALLOC_ENTRY_BLOCK, /* entry block */ +}; /** * nilfs_palloc_req - persistent allocator request and reply -- 1.7.3.5 -- To unsubscribe from this list: send the line "unsubscribe linux-nilfs" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
