udf: Handle error when adding extent to a file

When adding extent to a file fails, so far we've silently squelshed the
error. Make sure to propagate it up properly.
Signed-off-by: Jan Kara <jack@suse.cz>

fs/udf/inode.c

@@ -57,14 +57,14 @@ static int udf_update_inode(struct inode *, int);
 static int udf_sync_inode(struct inode *inode);
 static int udf_alloc_i_data(struct inode *inode, size_t size);
 static sector_t inode_getblk(struct inode *, sector_t, int *, int *);
-static int8_t udf_insert_aext(struct inode *, struct extent_position,
+static int udf_insert_aext(struct inode *, struct extent_position,
 			   struct kernel_lb_addr, uint32_t);
 static void udf_split_extents(struct inode *, int *, int, udf_pblk_t,
 			      struct kernel_long_ad *, int *);
 static void udf_prealloc_extents(struct inode *, int, int,
 				 struct kernel_long_ad *, int *);
 static void udf_merge_extents(struct inode *, struct kernel_long_ad *, int *);
-static void udf_update_extents(struct inode *, struct kernel_long_ad *, int,
+static int udf_update_extents(struct inode *, struct kernel_long_ad *, int,
 			      int, struct extent_position *);
 static int udf_get_block(struct inode *, sector_t, struct buffer_head *, int);
 
@@ -793,7 +793,9 @@ static sector_t inode_getblk(struct inode *inode, sector_t block,
 	/* write back the new extents, inserting new extents if the new number
 	 * of extents is greater than the old number, and deleting extents if
 	 * the new number of extents is less than the old number */
-	udf_update_extents(inode, laarr, startnum, endnum, &prev_epos);
+	*err = udf_update_extents(inode, laarr, startnum, endnum, &prev_epos);
+	if (*err < 0)
+		goto out_free;
 
 	newblock = udf_get_pblock(inode->i_sb, newblocknum,
 				iinfo->i_location.partitionReferenceNum, 0);
@@ -1061,21 +1063,30 @@ static void udf_merge_extents(struct inode *inode, struct kernel_long_ad *laarr,
 	}
 }
 
-static void udf_update_extents(struct inode *inode, struct kernel_long_ad *laarr,
+static int udf_update_extents(struct inode *inode, struct kernel_long_ad *laarr,
 			      int startnum, int endnum,
 			      struct extent_position *epos)
 {
 	int start = 0, i;
 	struct kernel_lb_addr tmploc;
 	uint32_t tmplen;
+	int err;
 
 	if (startnum > endnum) {
 		for (i = 0; i < (startnum - endnum); i++)
 			udf_delete_aext(inode, *epos);
 	} else if (startnum < endnum) {
 		for (i = 0; i < (endnum - startnum); i++) {
-			udf_insert_aext(inode, *epos, laarr[i].extLocation,
+			err = udf_insert_aext(inode, *epos,
+					      laarr[i].extLocation,
 					      laarr[i].extLength);
+			/*
+			 * If we fail here, we are likely corrupting the extent
+			 * list and leaking blocks. At least stop early to
+			 * limit the damage.
+			 */
+			if (err < 0)
+				return err;
 			udf_next_aext(inode, epos, &laarr[i].extLocation,
 				      &laarr[i].extLength, 1);
 			start++;
@@ -1087,6 +1098,7 @@ static void udf_update_extents(struct inode *inode, struct kernel_long_ad *laarr
 		udf_write_aext(inode, epos, &laarr[i].extLocation,
 			       laarr[i].extLength, 1);
 	}
+	return 0;
 }
 
 struct buffer_head *udf_bread(struct inode *inode, udf_pblk_t block,
@@ -2105,12 +2117,13 @@ int8_t udf_current_aext(struct inode *inode, struct extent_position *epos,
 	return etype;
 }
 
-static int8_t udf_insert_aext(struct inode *inode, struct extent_position epos,
+static int udf_insert_aext(struct inode *inode, struct extent_position epos,
 			   struct kernel_lb_addr neloc, uint32_t nelen)
 {
 	struct kernel_lb_addr oeloc;
 	uint32_t oelen;
 	int8_t etype;
+	int err;
 
 	if (epos.bh)
 		get_bh(epos.bh);
@@ -2120,10 +2133,10 @@ static int8_t udf_insert_aext(struct inode *inode, struct extent_position epos,
 		neloc = oeloc;
 		nelen = (etype << 30) | oelen;
 	}
-	udf_add_aext(inode, &epos, &neloc, nelen, 1);
+	err = udf_add_aext(inode, &epos, &neloc, nelen, 1);
 	brelse(epos.bh);
 
-	return (nelen >> 30);
+	return err;
 }
 
 int8_t udf_delete_aext(struct inode *inode, struct extent_position epos)