git: 010e3bc77275 - stable/13 - Avoid lost buffers in fsck_ffs.

[Kirk McKusick]

The branch stable/13 has been updated by mckusick:

URL: 
https://cgit.FreeBSD.org/src/commit/?id=010e3bc772753e282ccbf12df3600f6d1a33d3fe

commit 010e3bc772753e282ccbf12df3600f6d1a33d3fe
Author:     Kirk McKusick <mckus...@freebsd.org>
AuthorDate: 2021-10-07 22:51:56 +0000
Commit:     Kirk McKusick <mckus...@freebsd.org>
CommitDate: 2021-10-24 04:24:08 +0000

    Avoid lost buffers in fsck_ffs.
    
    Sponsored by: Netflix
    
    (cherry picked from commit 4313e2ae44ba4e416a7ddaeaccf8ad311902f1c8)
---
 sbin/fsck_ffs/inode.c | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/sbin/fsck_ffs/inode.c b/sbin/fsck_ffs/inode.c
index ba2d5892238e..dafc99bd92da 100644
--- a/sbin/fsck_ffs/inode.c
+++ b/sbin/fsck_ffs/inode.c
@@ -264,6 +264,8 @@ ino_blkatoff(union dinode *dp, ino_t ino, ufs_lbn_t lbn, 
int *frags,
        int i;
 
        *frags = 0;
+       if (bpp != NULL)
+               *bpp = NULL;
        /*
         * Handle extattr blocks first.
         */
@@ -300,6 +302,8 @@ ino_blkatoff(union dinode *dp, ino_t ino, ufs_lbn_t lbn, 
int *frags,
                        continue;
                if (lbn > 0 && lbn >= next)
                        continue;
+               if (DIP(dp, di_ib[i]) == 0)
+                       return (0);
                return (indir_blkatoff(DIP(dp, di_ib[i]), ino, -cur - i, lbn,
                    bpp));
        }
@@ -321,8 +325,6 @@ indir_blkatoff(ufs2_daddr_t blk, ino_t ino, ufs_lbn_t cur, 
ufs_lbn_t lbn,
        ufs_lbn_t base;
        int i, level;
 
-       if (blk == 0)
-               return (0);
        level = lbn_level(cur);
        if (level == -1)
                pfatal("Invalid indir lbn %jd in ino %ju\n",
@@ -352,12 +354,14 @@ indir_blkatoff(ufs2_daddr_t blk, ino_t ino, ufs_lbn_t 
cur, ufs_lbn_t lbn,
                return (0);
        blk = IBLK(bp, i);
        bp->b_index = i;
-       if (bpp != NULL)
-               *bpp = bp;
-       else
-               brelse(bp);
-       if (cur == lbn)
+       if (cur == lbn || blk == 0) {
+               if (bpp != NULL)
+                       *bpp = bp;
+               else
+                       brelse(bp);
                return (blk);
+       }
+       brelse(bp);
        if (level == 0)
                pfatal("Invalid lbn %jd at level 0 for ino %ju\n", lbn,
                    (uintmax_t)ino);