git: 57d877348b2c - stable/13 - Fix handling of embedded symbolic links (and history lesson).

[Kirk McKusick]

The branch stable/13 has been updated by mckusick:

URL: https://cgit.FreeBSD.org/src/commit/?id=57d877348b2cb53a502a1bd305f973105f064a58

commit 57d877348b2cb53a502a1bd305f973105f064a58
Author:     Kirk McKusick <mckusick at FreeBSD.org>
AuthorDate: 2021-05-17 00:02:42 +0000
Commit:     Kirk McKusick <mckusick at FreeBSD.org>
CommitDate: 2021-05-31 00:40:44 +0000

    Fix handling of embedded symbolic links (and history lesson).
    
    Sponsored by: Netflix
    
    (cherry picked from commit 9a2fac6ba65fbd14d37ccedbc2aec27a190128ea)
---
 sys/kern/vfs_subr.c     | 3 ++-
 sys/sys/mount.h         | 2 +-
 sys/ufs/ffs/ffs_inode.c | 4 +---
 sys/ufs/ufs/ufs_vnops.c | 4 +---
 4 files changed, 5 insertions(+), 8 deletions(-)

diff --git a/sys/kern/vfs_subr.c b/sys/kern/vfs_subr.c
index ee570f216b40..ba02d0600a6e 100644
--- a/sys/kern/vfs_subr.c
+++ b/sys/kern/vfs_subr.c
@@ -4403,7 +4403,8 @@ DB_SHOW_COMMAND(mount, db_show_mount)
 	    mp->mnt_lazyvnodelistsize);
 	db_printf("    mnt_writeopcount = %d (with %d in the struct)\n",
 	    vfs_mount_fetch_counter(mp, MNT_COUNT_WRITEOPCOUNT), mp->mnt_writeopcount);
-	db_printf("    mnt_maxsymlinklen = %d\n", mp->mnt_maxsymlinklen);
+	db_printf("    mnt_maxsymlinklen = %jd\n",
+	    (uintmax_t)mp->mnt_maxsymlinklen);
 	db_printf("    mnt_iosize_max = %d\n", mp->mnt_iosize_max);
 	db_printf("    mnt_hashseed = %u\n", mp->mnt_hashseed);
 	db_printf("    mnt_lockref = %d (with %d in the struct)\n",
diff --git a/sys/sys/mount.h b/sys/sys/mount.h
index 8b5712d19215..ae12c9fc8197 100644
--- a/sys/sys/mount.h
+++ b/sys/sys/mount.h
@@ -222,7 +222,7 @@ struct mount {
 	int		mnt_writeopcount;	/* (i) write syscalls pending */
 	struct vfsoptlist *mnt_opt;		/* current mount options */
 	struct vfsoptlist *mnt_optnew;		/* new options passed to fs */
-	int		mnt_maxsymlinklen;	/* max size of short symlink */
+	uint64_t	mnt_maxsymlinklen;	/* max size of short symlink */
 	struct statfs	mnt_stat;		/* cache of filesystem stats */
 	struct ucred	*mnt_cred;		/* credentials of mounter */
 	void *		mnt_data;		/* private data */
diff --git a/sys/ufs/ffs/ffs_inode.c b/sys/ufs/ffs/ffs_inode.c
index 3df7bf8e8596..7bb532e7d26c 100644
--- a/sys/ufs/ffs/ffs_inode.c
+++ b/sys/ufs/ffs/ffs_inode.c
@@ -329,9 +329,7 @@ ffs_truncate(vp, length, flags, cred)
 	}
 	if ((flags & IO_NORMAL) == 0)
 		return (0);
-	if (vp->v_type == VLNK &&
-	    (ip->i_size < vp->v_mount->mnt_maxsymlinklen ||
-	     datablocks == 0)) {
+	if (vp->v_type == VLNK && ip->i_size < vp->v_mount->mnt_maxsymlinklen) {
 #ifdef INVARIANTS
 		if (length != 0)
 			panic("ffs_truncate: partial truncate of symlink");
diff --git a/sys/ufs/ufs/ufs_vnops.c b/sys/ufs/ufs/ufs_vnops.c
index 301c583291d1..70bf1a1d9036 100644
--- a/sys/ufs/ufs/ufs_vnops.c
+++ b/sys/ufs/ufs/ufs_vnops.c
@@ -2458,10 +2458,8 @@ ufs_readlink(ap)
 	doff_t isize;
 
 	isize = ip->i_size;
-	if ((isize < vp->v_mount->mnt_maxsymlinklen) ||
-	    DIP(ip, i_blocks) == 0) { /* XXX - for old fastlink support */
+	if (isize < vp->v_mount->mnt_maxsymlinklen)
 		return (uiomove(SHORTLINK(ip), isize, ap->a_uio));
-	}
 	return (VOP_READ(vp, ap->a_uio, 0, ap->a_cred));
 }