Re: [PATCH 2/2] erofs: clean up erofs_map_blocks tracepoints

[Gao Xiang]

Hi Chao,

On Thu, Sep 23, 2021 at 10:13:23PM +0800, Chao Yu wrote:
> On 2021/9/21 22:35, Gao Xiang wrote:
> > Since the new type of chunk-based files is introduced, there is no
> > need to leave flatmode tracepoints. Rename to erofs_map_blocks.
> > 
> > Add the missing FIEMAP tracepoint map flag as well.
> > 
> > Signed-off-by: Gao Xiang <hsiangkao@xxxxxxxxxxxxxxxxx>
> > ---
> >   fs/erofs/data.c              | 31 ++++++++++++++-----------------
> >   include/trace/events/erofs.h |  7 ++++---
> >   2 files changed, 18 insertions(+), 20 deletions(-)
> > 
> > diff --git a/fs/erofs/data.c b/fs/erofs/data.c
> > index 9db8297..020c3e0 100644
> > --- a/fs/erofs/data.c
> > +++ b/fs/erofs/data.c
> > @@ -26,14 +26,11 @@ static int erofs_map_blocks_flatmode(struct inode *inode,
> >   				     struct erofs_map_blocks *map,
> >   				     int flags)
> >   {
> > -	int err = 0;
> >   	erofs_blk_t nblocks, lastblk;
> >   	u64 offset = map->m_la;
> >   	struct erofs_inode *vi = EROFS_I(inode);
> >   	bool tailendpacking = (vi->datalayout == EROFS_INODE_FLAT_INLINE);
> > -	trace_erofs_map_blocks_flatmode_enter(inode, map, flags);
> > -
> >   	nblocks = DIV_ROUND_UP(inode->i_size, PAGE_SIZE);
> >   	lastblk = nblocks - tailendpacking;
> > @@ -57,8 +54,7 @@ static int erofs_map_blocks_flatmode(struct inode *inode,
> >   				  "inline data cross block boundary @ nid %llu",
> >   				  vi->nid);
> >   			DBG_BUGON(1);
> > -			err = -EFSCORRUPTED;
> > -			goto err_out;
> > +			return -EFSCORRUPTED;
> >   		}
> >   		map->m_flags |= EROFS_MAP_META;
> > @@ -67,14 +63,10 @@ static int erofs_map_blocks_flatmode(struct inode *inode,
> >   			  "internal error @ nid: %llu (size %llu), m_la 0x%llx",
> >   			  vi->nid, inode->i_size, map->m_la);
> >   		DBG_BUGON(1);
> > -		err = -EIO;
> > -		goto err_out;
> > +		return -EIO;
> >   	}
> > -
> >   	map->m_llen = map->m_plen;
> > -err_out:
> > -	trace_erofs_map_blocks_flatmode_exit(inode, map, flags, 0);
> > -	return err;
> > +	return 0;
> >   }
> >   static int erofs_map_blocks(struct inode *inode,
> > @@ -89,6 +81,7 @@ static int erofs_map_blocks(struct inode *inode,
> >   	erofs_off_t pos;
> >   	int err = 0;
> > +	trace_erofs_map_blocks_enter(inode, map, flags);
> >   	if (map->m_la >= inode->i_size) {
> >   		/* leave out-of-bound access unmapped */
> >   		map->m_flags = 0;
> > @@ -96,8 +89,10 @@ static int erofs_map_blocks(struct inode *inode,
> 
> map->m_flags = 0;
> map->m_plen = 0;
> 
> It needs to reset map->m_llen to zero here like we did after 'out' label before?

Yeah, thanks for catching that! I will fix it in the next version
(PATCH 2/2 will be delayed for 5.16...)

p.s. I might need to apply the following patches for 5.15 cycle in
advance, could you help review these as well? Many thanks!
1. erofs: fix misbehavior of unsupported chunk format check
2. erofs: fix compacted_2b if compacted_4b_initial > totalidx

Thanks,
Gao Xiang

> 
> Thanks,
> 
> >   		goto out;
> >   	}
> > -	if (vi->datalayout != EROFS_INODE_CHUNK_BASED)
> > -		return erofs_map_blocks_flatmode(inode, map, flags);
> > +	if (vi->datalayout != EROFS_INODE_CHUNK_BASED) {
> > +		err = erofs_map_blocks_flatmode(inode, map, flags);
> > +		goto out;
> > +	}
> >   	if (vi->chunkformat & EROFS_CHUNK_FORMAT_INDEXES)
> >   		unit = sizeof(*idx);			/* chunk index */
> > @@ -109,9 +104,10 @@ static int erofs_map_blocks(struct inode *inode,
> >   		    vi->xattr_isize, unit) + unit * chunknr;
> >   	page = erofs_get_meta_page(inode->i_sb, erofs_blknr(pos));
> > -	if (IS_ERR(page))
> > -		return PTR_ERR(page);
> > -
> > +	if (IS_ERR(page)) {
> > +		err = PTR_ERR(page);
> > +		goto out;
> > +	}
> >   	map->m_la = chunknr << vi->chunkbits;
> >   	map->m_plen = min_t(erofs_off_t, 1UL << vi->chunkbits,
> >   			    roundup(inode->i_size - map->m_la, EROFS_BLKSIZ));
> > @@ -147,11 +143,12 @@ static int erofs_map_blocks(struct inode *inode,
> >   		map->m_flags = EROFS_MAP_MAPPED;
> >   		break;
> >   	}
> > +	map->m_llen = map->m_plen;
> >   out_unlock:
> >   	unlock_page(page);
> >   	put_page(page);
> >   out:
> > -	map->m_llen = map->m_plen;
> > +	trace_erofs_map_blocks_exit(inode, map, flags, 0);
> >   	return err;
> >   }
> > diff --git a/include/trace/events/erofs.h b/include/trace/events/erofs.h
> > index db4f2ce..5c91edd 100644
> > --- a/include/trace/events/erofs.h
> > +++ b/include/trace/events/erofs.h
> > @@ -19,7 +19,8 @@
> >   		{ 1,		"DIR" })
> >   #define show_map_flags(flags) __print_flags(flags, "|",	\
> > -	{ EROFS_GET_BLOCKS_RAW,	"RAW" })
> > +	{ EROFS_GET_BLOCKS_RAW,	"RAW" },		\
> > +	{ EROFS_GET_BLOCKS_FIEMAP, "FIEMAP" })
> >   #define show_mflags(flags) __print_flags(flags, "",	\
> >   	{ EROFS_MAP_MAPPED,	"M" },			\
> > @@ -169,7 +170,7 @@
> >   		  __entry->flags ? show_map_flags(__entry->flags) : "NULL")
> >   );
> > -DEFINE_EVENT(erofs__map_blocks_enter, erofs_map_blocks_flatmode_enter,
> > +DEFINE_EVENT(erofs__map_blocks_enter, erofs_map_blocks_enter,
> >   	TP_PROTO(struct inode *inode, struct erofs_map_blocks *map,
> >   		 unsigned flags),
> > @@ -221,7 +222,7 @@
> >   		  show_mflags(__entry->mflags), __entry->ret)
> >   );
> > -DEFINE_EVENT(erofs__map_blocks_exit, erofs_map_blocks_flatmode_exit,
> > +DEFINE_EVENT(erofs__map_blocks_exit, erofs_map_blocks_exit,
> >   	TP_PROTO(struct inode *inode, struct erofs_map_blocks *map,
> >   		 unsigned flags, int ret),
> >