[lvc-project] [PATCH 5.10 1/1] udf: Handle error when adding extent to a file

[Vladislav Efanov]

From: Jan Kara <jack at suse.cz>

commit 19fd80de0a8b5170ef34704c8984cca920dffa59 upstream

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 at suse.cz>
Signed-off-by: Vladislav Efanov <VEfanov at ispras.ru>
---
Syzkaller reports this problem in 5.10 stable release. The problem has
been fixed by the following patch which can be cleanly applied to the
5.10 branch.
 fs/udf/inode.c | 41 +++++++++++++++++++++++++++--------------
 1 file changed, 27 insertions(+), 14 deletions(-)

diff --git a/fs/udf/inode.c b/fs/udf/inode.c
index d114774ecdea..3e11190b7118 100644
--- a/fs/udf/inode.c
+++ b/fs/udf/inode.c
@@ -57,15 +57,15 @@ 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,
-			      struct kernel_lb_addr, uint32_t);
+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,
-			       int, struct extent_position *);
+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);
 
 static void __udf_clear_extent_cache(struct inode *inode)
@@ -887,7 +887,9 @@ 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);
@@ -1155,21 +1157,30 @@ 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,
-			       int startnum, int endnum,
-			       struct extent_position *epos)
+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,
-					laarr[i].extLength);
+			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++;
@@ -1181,6 +1192,7 @@ 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,
@@ -2215,12 +2227,13 @@ 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,
-			      struct kernel_lb_addr neloc, uint32_t nelen)
+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);
@@ -2230,10 +2243,10 @@ 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)
-- 
2.34.1