static int nilfs_mdt_submit_block(struct inode *inode, unsigned long blkoff, int mode, struct buffer_head **out_bh) { struct buffer_head *bh; unsigned long blknum = 0; int ret = -ENOMEM; bh = nilfs_grab_buffer(inode, inode->i_mapping, blkoff, 0); if (unlikely(!bh)) goto failed; ret = -EEXIST; /* internal code */ if (buffer_uptodate(bh)) goto out; if (mode == READA) { if (!trylock_buffer(bh)) { ret = -EBUSY; goto failed_bh; } } else /* mode == READ */ lock_buffer(bh); if (buffer_uptodate(bh)) { unlock_buffer(bh); goto out; } if (!buffer_mapped(bh)) { /* unused buffer */ ret = nilfs_bmap_lookup(NILFS_I(inode)->i_bmap, blkoff, &blknum); if (unlikely(ret)) { unlock_buffer(bh); goto failed_bh; } bh->b_bdev = NILFS_MDT(inode)->mi_nilfs->ns_bdev; bh->b_blocknr = blknum; set_buffer_mapped(bh); } bh->b_end_io = end_buffer_read_sync; get_bh(bh); submit_bh(mode, bh); ret = 0; out: get_bh(bh); *out_bh = bh; failed_bh: unlock_page(bh->b_page); page_cache_release(bh->b_page); brelse(bh); failed: return ret; }
static int nilfs_mdt_submit_block(struct inode *inode, unsigned long blkoff, int mode, int mode_flags, struct buffer_head **out_bh) { struct buffer_head *bh; __u64 blknum = 0; int ret = -ENOMEM; bh = nilfs_grab_buffer(inode, inode->i_mapping, blkoff, 0); if (unlikely(!bh)) goto failed; ret = -EEXIST; /* internal code */ if (buffer_uptodate(bh)) goto out; if (mode_flags & REQ_RAHEAD) { if (!trylock_buffer(bh)) { ret = -EBUSY; goto failed_bh; } } else /* mode == READ */ lock_buffer(bh); if (buffer_uptodate(bh)) { unlock_buffer(bh); goto out; } ret = nilfs_bmap_lookup(NILFS_I(inode)->i_bmap, blkoff, &blknum); if (unlikely(ret)) { unlock_buffer(bh); goto failed_bh; } map_bh(bh, inode->i_sb, (sector_t)blknum); bh->b_end_io = end_buffer_read_sync; get_bh(bh); submit_bh(mode, mode_flags, bh); ret = 0; trace_nilfs2_mdt_submit_block(inode, inode->i_ino, blkoff, mode); out: get_bh(bh); *out_bh = bh; failed_bh: unlock_page(bh->b_page); put_page(bh->b_page); brelse(bh); failed: return ret; }
/** * nilfs_get_block() - get a file block on the filesystem (callback function) * @inode - inode struct of the target file * @blkoff - file block number * @bh_result - buffer head to be mapped on * @create - indicate whether allocating the block or not when it has not * been allocated yet. * * This function does not issue actual read request of the specified data * block. It is done by VFS. * Bulk read for direct-io is not supported yet. (should be supported) */ int nilfs_get_block(struct inode *inode, sector_t blkoff, struct buffer_head *bh_result, int create) { struct nilfs_inode_info *ii = NILFS_I(inode); unsigned long blknum = 0; int err = 0, ret; struct inode *dat = nilfs_dat_inode(NILFS_I_NILFS(inode)); /* This exclusion control is a workaround; should be revised */ down_read(&NILFS_MDT(dat)->mi_sem); /* XXX */ ret = nilfs_bmap_lookup(ii->i_bmap, (unsigned long)blkoff, &blknum); up_read(&NILFS_MDT(dat)->mi_sem); /* XXX */ if (ret == 0) { /* found */ map_bh(bh_result, inode->i_sb, blknum); goto out; } /* data block was not found */ if (ret == -ENOENT && create) { struct nilfs_transaction_info ti; bh_result->b_blocknr = 0; err = nilfs_transaction_begin(inode->i_sb, &ti, 1); if (unlikely(err)) goto out; err = nilfs_bmap_insert(ii->i_bmap, (unsigned long)blkoff, (unsigned long)bh_result); if (unlikely(err != 0)) { if (err == -EEXIST) { /* * The get_block() function could be called * from multiple callers for an inode. * However, the page having this block must * be locked in this case. */ printk(KERN_WARNING "nilfs_get_block: a race condition " "while inserting a data block. " "(inode number=%lu, file block " "offset=%llu)\n", inode->i_ino, (unsigned long long)blkoff); err = 0; } else if (err == -EINVAL) { nilfs_error(inode->i_sb, __func__, "broken bmap (inode=%lu)\n", inode->i_ino); err = -EIO; } nilfs_transaction_abort(inode->i_sb); goto out; } nilfs_transaction_commit(inode->i_sb); /* never fails */ /* Error handling should be detailed */ set_buffer_new(bh_result); map_bh(bh_result, inode->i_sb, 0); /* dbn must be changed to proper value */ } else if (ret == -ENOENT) { /* not found is not error (e.g. hole); must return without the mapped state flag. */ ; } else { err = ret; } out: return err; }