[PATCH 1/3] udf: refactor udf_current_aext() to handle error

Zhao Mengmeng posted 3 patches 2 months, 1 week ago
[PATCH 1/3] udf: refactor udf_current_aext() to handle error
Posted by Zhao Mengmeng 2 months, 1 week ago
From: Zhao Mengmeng <zhaomengmeng@kylinos.cn>

As Jan suggested in links below, refactor udf_current_aext() to
differentiate between error and "hit EOF", it now takes pointer to etype
to store the extent type, return 0 when get etype success; return -ENODATA
when hit EOF; return -EINVAL when i_alloc_type invalid.

Link: https://lore.kernel.org/all/20240912111235.6nr3wuqvktecy3vh@quack3/

Signed-off-by: Zhao Mengmeng <zhaomengmeng@kylinos.cn>
---
 fs/udf/inode.c    | 37 +++++++++++++++++++++++--------------
 fs/udf/truncate.c |  3 +--
 fs/udf/udfdecl.h  |  5 +++--
 3 files changed, 27 insertions(+), 18 deletions(-)

diff --git a/fs/udf/inode.c b/fs/udf/inode.c
index 4726a4d014b6..6d41ca0e7dba 100644
--- a/fs/udf/inode.c
+++ b/fs/udf/inode.c
@@ -1955,6 +1955,7 @@ int udf_setup_indirect_aext(struct inode *inode, udf_pblk_t block,
 	struct extent_position nepos;
 	struct kernel_lb_addr neloc;
 	int ver, adsize;
+	int err = 0;
 
 	if (UDF_I(inode)->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
 		adsize = sizeof(struct short_ad);
@@ -1999,10 +2000,12 @@ int udf_setup_indirect_aext(struct inode *inode, udf_pblk_t block,
 	if (epos->offset + adsize > sb->s_blocksize) {
 		struct kernel_lb_addr cp_loc;
 		uint32_t cp_len;
-		int cp_type;
+		int8_t cp_type;
 
 		epos->offset -= adsize;
-		cp_type = udf_current_aext(inode, epos, &cp_loc, &cp_len, 0);
+		err = udf_current_aext(inode, epos, &cp_loc, &cp_len, &cp_type, 0);
+		if (err < 0)
+			goto err_out;
 		cp_len |= ((uint32_t)cp_type) << 30;
 
 		__udf_add_aext(inode, &nepos, &cp_loc, cp_len, 1);
@@ -2017,6 +2020,9 @@ int udf_setup_indirect_aext(struct inode *inode, udf_pblk_t block,
 	*epos = nepos;
 
 	return 0;
+err_out:
+	brelse(epos->bh);
+	return err;
 }
 
 /*
@@ -2167,9 +2173,12 @@ int8_t udf_next_aext(struct inode *inode, struct extent_position *epos,
 {
 	int8_t etype;
 	unsigned int indirections = 0;
+	int err = 0;
+
+	while ((err = udf_current_aext(inode, epos, eloc, elen, &etype, inc))) {
+		if (err || etype != (EXT_NEXT_EXTENT_ALLOCDESCS >> 30))
+			break;
 
-	while ((etype = udf_current_aext(inode, epos, eloc, elen, inc)) ==
-	       (EXT_NEXT_EXTENT_ALLOCDESCS >> 30)) {
 		udf_pblk_t block;
 
 		if (++indirections > UDF_MAX_INDIR_EXTS) {
@@ -2190,14 +2199,14 @@ int8_t udf_next_aext(struct inode *inode, struct extent_position *epos,
 		}
 	}
 
-	return etype;
+	return err;
 }
 
-int8_t udf_current_aext(struct inode *inode, struct extent_position *epos,
-			struct kernel_lb_addr *eloc, uint32_t *elen, int inc)
+int udf_current_aext(struct inode *inode, struct extent_position *epos,
+		     struct kernel_lb_addr *eloc, uint32_t *elen, int8_t *etype,
+		     int inc)
 {
 	int alen;
-	int8_t etype;
 	uint8_t *ptr;
 	struct short_ad *sad;
 	struct long_ad *lad;
@@ -2224,8 +2233,8 @@ int8_t udf_current_aext(struct inode *inode, struct extent_position *epos,
 	case ICBTAG_FLAG_AD_SHORT:
 		sad = udf_get_fileshortad(ptr, alen, &epos->offset, inc);
 		if (!sad)
-			return -1;
-		etype = le32_to_cpu(sad->extLength) >> 30;
+			return -ENODATA;
+		*etype = le32_to_cpu(sad->extLength) >> 30;
 		eloc->logicalBlockNum = le32_to_cpu(sad->extPosition);
 		eloc->partitionReferenceNum =
 				iinfo->i_location.partitionReferenceNum;
@@ -2234,17 +2243,17 @@ int8_t udf_current_aext(struct inode *inode, struct extent_position *epos,
 	case ICBTAG_FLAG_AD_LONG:
 		lad = udf_get_filelongad(ptr, alen, &epos->offset, inc);
 		if (!lad)
-			return -1;
-		etype = le32_to_cpu(lad->extLength) >> 30;
+			return -ENODATA;
+		*etype = le32_to_cpu(lad->extLength) >> 30;
 		*eloc = lelb_to_cpu(lad->extLocation);
 		*elen = le32_to_cpu(lad->extLength) & UDF_EXTENT_LENGTH_MASK;
 		break;
 	default:
 		udf_debug("alloc_type = %u unsupported\n", iinfo->i_alloc_type);
-		return -1;
+		return -EINVAL;
 	}
 
-	return etype;
+	return 0;
 }
 
 static int udf_insert_aext(struct inode *inode, struct extent_position epos,
diff --git a/fs/udf/truncate.c b/fs/udf/truncate.c
index a686c10fd709..91b6e2698e7e 100644
--- a/fs/udf/truncate.c
+++ b/fs/udf/truncate.c
@@ -217,8 +217,7 @@ int udf_truncate_extents(struct inode *inode)
 	else
 		lenalloc -= sizeof(struct allocExtDesc);
 
-	while ((etype = udf_current_aext(inode, &epos, &eloc,
-					 &elen, 0)) != -1) {
+	while (!udf_current_aext(inode, &epos, &eloc, &elen, &etype, 0)) {
 		if (etype == (EXT_NEXT_EXTENT_ALLOCDESCS >> 30)) {
 			udf_write_aext(inode, &epos, &neloc, nelen, 0);
 			if (indirect_ext_len) {
diff --git a/fs/udf/udfdecl.h b/fs/udf/udfdecl.h
index 88692512a466..d893db95ac70 100644
--- a/fs/udf/udfdecl.h
+++ b/fs/udf/udfdecl.h
@@ -171,8 +171,9 @@ extern void udf_write_aext(struct inode *, struct extent_position *,
 extern int8_t udf_delete_aext(struct inode *, struct extent_position);
 extern int8_t udf_next_aext(struct inode *, struct extent_position *,
 			    struct kernel_lb_addr *, uint32_t *, int);
-extern int8_t udf_current_aext(struct inode *, struct extent_position *,
-			       struct kernel_lb_addr *, uint32_t *, int);
+extern int udf_current_aext(struct inode *inode, struct extent_position *epos,
+			    struct kernel_lb_addr *eloc, uint32_t *elen,
+			    int8_t *etype, int inc);
 extern void udf_update_extra_perms(struct inode *inode, umode_t mode);
 
 /* misc.c */
-- 
2.43.0
Re: [PATCH 1/3] udf: refactor udf_current_aext() to handle error
Posted by Jan Kara 2 months, 1 week ago
On Wed 18-09-24 17:36:32, Zhao Mengmeng wrote:
> From: Zhao Mengmeng <zhaomengmeng@kylinos.cn>
> 
> As Jan suggested in links below, refactor udf_current_aext() to
> differentiate between error and "hit EOF", it now takes pointer to etype
> to store the extent type, return 0 when get etype success; return -ENODATA
> when hit EOF; return -EINVAL when i_alloc_type invalid.
> 
> Link: https://lore.kernel.org/all/20240912111235.6nr3wuqvktecy3vh@quack3/
> 
> Signed-off-by: Zhao Mengmeng <zhaomengmeng@kylinos.cn>

Two comments below.

> @@ -1999,10 +2000,12 @@ int udf_setup_indirect_aext(struct inode *inode, udf_pblk_t block,
>  	if (epos->offset + adsize > sb->s_blocksize) {
>  		struct kernel_lb_addr cp_loc;
>  		uint32_t cp_len;
> -		int cp_type;
> +		int8_t cp_type;
>  
>  		epos->offset -= adsize;
> -		cp_type = udf_current_aext(inode, epos, &cp_loc, &cp_len, 0);
> +		err = udf_current_aext(inode, epos, &cp_loc, &cp_len, &cp_type, 0);
> +		if (err < 0)
> +			goto err_out;
>  		cp_len |= ((uint32_t)cp_type) << 30;
>  
>  		__udf_add_aext(inode, &nepos, &cp_loc, cp_len, 1);
> @@ -2017,6 +2020,9 @@ int udf_setup_indirect_aext(struct inode *inode, udf_pblk_t block,
>  	*epos = nepos;
>  
>  	return 0;
> +err_out:
> +	brelse(epos->bh);
> +	return err;
>  }

So here I don't think we want to release epos->bh. Rather we need to
release 'bh' itself which we have got because we did't replace epos->bh yet
with it.

> @@ -2167,9 +2173,12 @@ int8_t udf_next_aext(struct inode *inode, struct extent_position *epos,
>  {
>  	int8_t etype;
>  	unsigned int indirections = 0;
> +	int err = 0;
> +
> +	while ((err = udf_current_aext(inode, epos, eloc, elen, &etype, inc))) {
> +		if (err || etype != (EXT_NEXT_EXTENT_ALLOCDESCS >> 30))
> +			break;
>  
> -	while ((etype = udf_current_aext(inode, epos, eloc, elen, inc)) ==
> -	       (EXT_NEXT_EXTENT_ALLOCDESCS >> 30)) {
>  		udf_pblk_t block;
>  
>  		if (++indirections > UDF_MAX_INDIR_EXTS) {
> @@ -2190,14 +2199,14 @@ int8_t udf_next_aext(struct inode *inode, struct extent_position *epos,
>  		}
>  	}
>  
> -	return etype;
> +	return err;
>  }

This doesn't look right. Probably it gets fixed up in the following patches
but here should be something like: !err ? etype : -1
to keep udf_next_aext() compatible with its users.

Otherwise the patch looks good.

								Honza

-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR
Re: [PATCH 1/3] udf: refactor udf_current_aext() to handle error
Posted by Zhao Mengmeng 2 months, 1 week ago
On 2024/9/20 23:09, Jan Kara wrote:
> On Wed 18-09-24 17:36:32, Zhao Mengmeng wrote:
>> From: Zhao Mengmeng <zhaomengmeng@kylinos.cn>
>>
>> As Jan suggested in links below, refactor udf_current_aext() to
>> differentiate between error and "hit EOF", it now takes pointer to etype
>> to store the extent type, return 0 when get etype success; return -ENODATA
>> when hit EOF; return -EINVAL when i_alloc_type invalid.
>>
>> Link: https://lore.kernel.org/all/20240912111235.6nr3wuqvktecy3vh@quack3/
>>
>> Signed-off-by: Zhao Mengmeng <zhaomengmeng@kylinos.cn>
> 
> Two comments below.
> 
>> @@ -1999,10 +2000,12 @@ int udf_setup_indirect_aext(struct inode *inode, udf_pblk_t block,
>>  	if (epos->offset + adsize > sb->s_blocksize) {
>>  		struct kernel_lb_addr cp_loc;
>>  		uint32_t cp_len;
>> -		int cp_type;
>> +		int8_t cp_type;
>>  
>>  		epos->offset -= adsize;
>> -		cp_type = udf_current_aext(inode, epos, &cp_loc, &cp_len, 0);
>> +		err = udf_current_aext(inode, epos, &cp_loc, &cp_len, &cp_type, 0);
>> +		if (err < 0)
>> +			goto err_out;
>>  		cp_len |= ((uint32_t)cp_type) << 30;
>>  
>>  		__udf_add_aext(inode, &nepos, &cp_loc, cp_len, 1);
>> @@ -2017,6 +2020,9 @@ int udf_setup_indirect_aext(struct inode *inode, udf_pblk_t block,
>>  	*epos = nepos;
>>  
>>  	return 0;
>> +err_out:
>> +	brelse(epos->bh);
>> +	return err;
>>  }
> 
> So here I don't think we want to release epos->bh. Rather we need to
> release 'bh' itself which we have got because we did't replace epos->bh yet
> with it.
Yes, should be bh as we haven't done `*epos = nepos`. Will fix.
 
>> @@ -2167,9 +2173,12 @@ int8_t udf_next_aext(struct inode *inode, struct extent_position *epos,
>>  {
>>  	int8_t etype;
>>  	unsigned int indirections = 0;
>> +	int err = 0;
>> +
>> +	while ((err = udf_current_aext(inode, epos, eloc, elen, &etype, inc))) {
>> +		if (err || etype != (EXT_NEXT_EXTENT_ALLOCDESCS >> 30))
>> +			break;
>>  
>> -	while ((etype = udf_current_aext(inode, epos, eloc, elen, inc)) ==
>> -	       (EXT_NEXT_EXTENT_ALLOCDESCS >> 30)) {
>>  		udf_pblk_t block;
>>  
>>  		if (++indirections > UDF_MAX_INDIR_EXTS) {
>> @@ -2190,14 +2199,14 @@ int8_t udf_next_aext(struct inode *inode, struct extent_position *epos,
>>  		}
>>  	}
>>  
>> -	return etype;
>> +	return err;
>>  }
> 
> This doesn't look right. Probably it gets fixed up in the following patches
> but here should be something like: !err ? etype : -1
> to keep udf_next_aext() compatible with its users.
> 
> Otherwise the patch looks good.
> 
> 								Honza
> 

Will do