[RFC PATCH] erofs-utils: fsck: support fragments

[Yue Hu]

Hi Xiang,

On Wed, 4 Jan 2023 10:48:40 +0800
Xiang Gao <hsiangkao at linux.alibaba.com> wrote:

> Hi Yue,
> 
> 在 2022/12/24 17:43, Yue Hu 写道:
> > From: Yue Hu <huyue2 at coolpad.com>
> > 
> > Add compressed fragments support for fsck.erofs.
> > 
> > Signed-off-by: Yue Hu <huyue2 at coolpad.com>
> > ---
> >   fsck/main.c | 41 +++++++++++++++++++++++++++++++++++++++--
> >   lib/zmap.c  |  1 +
> >   2 files changed, 40 insertions(+), 2 deletions(-)
> > 
> > diff --git a/fsck/main.c b/fsck/main.c
> > index 2a9c501..9babc61 100644
> > --- a/fsck/main.c
> > +++ b/fsck/main.c
> > @@ -421,6 +421,31 @@ static int erofs_verify_inode_data(struct erofs_inode *inode, int outfd)
> >   		if (!(map.m_flags & EROFS_MAP_MAPPED) || !fsckcfg.check_decomp)
> >   			continue;
> >   
> > +		if (map.m_flags & EROFS_MAP_FRAGMENT) {
> > +			struct erofs_inode packed_inode = {
> > +				.nid = sbi.packed_nid,
> > +			};  
> 
> Sorry for late response.
> 
> a question... why don't we just rely on z_erofs_read_data()?

We may fall back to uncompressed mode for packed inode due to 'ENOSPC'.

> 
> 
> Thanks,
> Gao Xiang
> 
> > +
> > +			ret = erofs_read_inode_from_disk(&packed_inode);
> > +			if (ret) {
> > +				erofs_err("failed to read packed inode from disk");
> > +				goto out;
> > +			}
> > +
> > +			if (!buffer || map.m_llen > buffer_size) {
> > +				buffer_size = map.m_llen;
> > +				buffer = realloc(buffer, map.m_llen);
> > +				BUG_ON(!buffer);
> > +			}
> > +			ret = erofs_pread(&packed_inode, buffer, map.m_llen,
> > +					  inode->fragmentoff);
> > +			if (ret)
> > +				goto out;
> > +
> > +			compressed = true;	/* force using buffer */
> > +			goto write_outfd;
> > +		}
> > +
> >   		if (map.m_plen > raw_size) {
> >   			raw_size = map.m_plen;
> >   			raw = realloc(raw, raw_size);
> > @@ -476,6 +501,7 @@ static int erofs_verify_inode_data(struct erofs_inode *inode, int outfd)
> >   			}
> >   		}
> >   
> > +write_outfd:
> >   		if (outfd >= 0 && write(outfd, compressed ? buffer : raw,
> >   					map.m_llen) < 0) {
> >   			erofs_err("I/O error occurred when verifying data chunk @ nid %llu",
> > @@ -486,8 +512,9 @@ static int erofs_verify_inode_data(struct erofs_inode *inode, int outfd)
> >   	}
> >   
> >   	if (fsckcfg.print_comp_ratio) {
> > -		fsckcfg.logical_blocks += BLK_ROUND_UP(inode->i_size);
> >   		fsckcfg.physical_blocks += BLK_ROUND_UP(pchunk_len);
> > +		if (!erofs_is_packed_inode(inode))
> > +			fsckcfg.logical_blocks += BLK_ROUND_UP(inode->i_size);
> >   	}
> >   out:
> >   	if (raw)
> > @@ -732,6 +759,8 @@ static int erofsfsck_check_inode(erofs_nid_t pnid, erofs_nid_t nid)
> >   			ret = erofs_extract_dir(&inode);
> >   			break;
> >   		case S_IFREG:
> > +			if (erofs_is_packed_inode(&inode))
> > +				goto verify;
> >   			ret = erofs_extract_file(&inode);
> >   			break;
> >   		case S_IFLNK:
> > @@ -767,7 +796,7 @@ verify:
> >   		ret = erofs_iterate_dir(&ctx, true);
> >   	}
> >   
> > -	if (!ret)
> > +	if (!ret && !erofs_is_packed_inode(&inode))
> >   		erofsfsck_set_attributes(&inode, fsckcfg.extract_path);
> >   
> >   	if (ret == -ECANCELED)
> > @@ -822,6 +851,14 @@ int main(int argc, char **argv)
> >   		goto exit_put_super;
> >   	}
> >   
> > +	if (erofs_sb_has_fragments()) {
> > +		err = erofsfsck_check_inode(sbi.packed_nid, sbi.packed_nid);
> > +		if (err) {
> > +			erofs_err("failed to verify packed file");
> > +			goto exit_put_super;
> > +		}
> > +	}
> > +
> >   	err = erofsfsck_check_inode(sbi.root_nid, sbi.root_nid);
> >   	if (fsckcfg.corrupted) {
> >   		if (!fsckcfg.extract_path)
> > diff --git a/lib/zmap.c b/lib/zmap.c
> > index 41e0713..ca65038 100644
> > --- a/lib/zmap.c
> > +++ b/lib/zmap.c
> > @@ -639,6 +639,7 @@ static int z_erofs_do_map_blocks(struct erofs_inode *vi,
> >   		map->m_plen = vi->z_idata_size;
> >   	} else if (fragment && m.lcn == vi->z_tailextent_headlcn) {
> >   		map->m_flags |= EROFS_MAP_FRAGMENT;
> > +		map->m_plen = 0;
> >   	} else {
> >   		map->m_pa = blknr_to_addr(m.pblk);
> >   		err = z_erofs_get_extent_compressedlen(&m, initial_lcn);