git: f2c72486da30 - releng/13.3 - fusefs: fix invalid value for st_birthtime.tv_nsec

From: Alan Somers <asomers_at_FreeBSD.org>
Date: Mon, 12 Feb 2024 20:17:51 UTC
The branch releng/13.3 has been updated by asomers:

URL: https://cgit.FreeBSD.org/src/commit/?id=f2c72486da30eda54f0db1a9b7ca822afc835ecf

commit f2c72486da30eda54f0db1a9b7ca822afc835ecf
Author:     Alan Somers <asomers@FreeBSD.org>
AuthorDate: 2024-01-25 15:19:37 +0000
Commit:     Alan Somers <asomers@FreeBSD.org>
CommitDate: 2024-02-12 20:17:13 +0000

    fusefs: fix invalid value for st_birthtime.tv_nsec
    
    If a file system's on-disk format does not support st_birthtime, it
    isn't clear what value it should return in stat(2).  Neither our man
    page nor the OpenGroup specifies.  But our convention for UFS and
    msdosfs is to return { .tv_sec = -1, .tv_nsec = 0 }.  fusefs is
    different.  It returns { .tv_sec = -1, .tv_nsec = -1 }.  It's done that
    ever since the initial import in SVN r241519.
    
    Most software apparently handles this just fine.  It must, because we've
    had no complaints.  But the Rust standard library will panic when
    reading such a timestamp during std::fs::metadata, even if the caller
    doesn't care about that particular value.  That's a separate bug, and
    should be fixed.
    
    Change our invalid value to match msdosfs and ufs, pacifying the Rust
    standard library.
    
    PR:             276602
    Sponsored by:   Axcient
    Reviewed by:    emaste
    Approved by:    re (cperciva)
    Differential Revision: https://reviews.freebsd.org/D43590
    
    (cherry picked from commit 65e25e4a614a99243e7419279b294e399991dfff)
---
 sys/fs/fuse/fuse_internal.c    |  1 -
 sys/fs/fuse/fuse_node.c        |  7 +++++++
 tests/sys/fs/fusefs/getattr.cc | 15 +++++++++------
 tests/sys/fs/fusefs/lookup.cc  | 15 +++++++++------
 4 files changed, 25 insertions(+), 13 deletions(-)

diff --git a/sys/fs/fuse/fuse_internal.c b/sys/fs/fuse/fuse_internal.c
index 13d18127d2e6..c851cb2e34f4 100644
--- a/sys/fs/fuse/fuse_internal.c
+++ b/sys/fs/fuse/fuse_internal.c
@@ -326,7 +326,6 @@ fuse_internal_cache_attrs(struct vnode *vp, struct fuse_attr *attr,
 	else
 		return;
 
-	vattr_null(vp_cache_at);
 	vp_cache_at->va_fsid = mp->mnt_stat.f_fsid.val[0];
 	vp_cache_at->va_fileid = attr->ino;
 	vp_cache_at->va_mode = attr->mode & ~S_IFMT;
diff --git a/sys/fs/fuse/fuse_node.c b/sys/fs/fuse/fuse_node.c
index a02b41e24ad8..52bd2d92f4da 100644
--- a/sys/fs/fuse/fuse_node.c
+++ b/sys/fs/fuse/fuse_node.c
@@ -156,7 +156,14 @@ fuse_vnode_init(struct vnode *vp, struct fuse_vnode_data *fvdat,
 {
 	fvdat->nid = nodeid;
 	LIST_INIT(&fvdat->handles);
+
 	vattr_null(&fvdat->cached_attrs);
+	fvdat->cached_attrs.va_birthtime.tv_sec = -1;
+	fvdat->cached_attrs.va_birthtime.tv_nsec = 0;
+	fvdat->cached_attrs.va_fsid = VNOVAL;
+	fvdat->cached_attrs.va_gen = 0;
+	fvdat->cached_attrs.va_rdev = NODEV;
+
 	if (nodeid == FUSE_ROOT_ID) {
 		vp->v_vflag |= VV_ROOT;
 	}
diff --git a/tests/sys/fs/fusefs/getattr.cc b/tests/sys/fs/fusefs/getattr.cc
index 1795f29a5d76..98a757fdff94 100644
--- a/tests/sys/fs/fusefs/getattr.cc
+++ b/tests/sys/fs/fusefs/getattr.cc
@@ -246,12 +246,15 @@ TEST_F(Getattr, ok)
 	EXPECT_EQ(ino, sb.st_ino);
 	EXPECT_EQ(S_IFREG | 0644, sb.st_mode);
 
-	//st_birthtim and st_flags are not supported by protocol 7.8.  They're
-	//only supported as OS-specific extensions to OSX.
-	//EXPECT_EQ(, sb.st_birthtim);
-	//EXPECT_EQ(, sb.st_flags);
-	
-	//FUSE can't set st_blksize until protocol 7.9
+	/*
+	 * st_birthtim and st_flags are not supported by the fuse protocol.
+	 * They're only supported as OS-specific extensions to OSX.  For
+	 * birthtime, the convention for "not supported" is "negative one
+	 * second".
+	 */
+	EXPECT_EQ(-1, sb.st_birthtim.tv_sec);
+	EXPECT_EQ(0, sb.st_birthtim.tv_nsec);
+	EXPECT_EQ(0u, sb.st_flags);
 }
 
 /*
diff --git a/tests/sys/fs/fusefs/lookup.cc b/tests/sys/fs/fusefs/lookup.cc
index 549df0369fa7..6d506c1ab700 100644
--- a/tests/sys/fs/fusefs/lookup.cc
+++ b/tests/sys/fs/fusefs/lookup.cc
@@ -112,12 +112,15 @@ TEST_F(Lookup, attr_cache)
 	// fuse(4) does not _yet_ support inode generations
 	//EXPECT_EQ(generation, sb.st_gen);
 
-	//st_birthtim and st_flags are not supported by protocol 7.8.  They're
-	//only supported as OS-specific extensions to OSX.
-	//EXPECT_EQ(, sb.st_birthtim);
-	//EXPECT_EQ(, sb.st_flags);
-	
-	//FUSE can't set st_blksize until protocol 7.9
+	/*
+	 * st_birthtim and st_flags are not supported by the fuse protocol.
+	 * They're only supported as OS-specific extensions to OSX.  For
+	 * birthtime, the convention for "not supported" is "negative one
+	 * second".
+	 */
+	EXPECT_EQ(-1, sb.st_birthtim.tv_sec);
+	EXPECT_EQ(0, sb.st_birthtim.tv_nsec);
+	EXPECT_EQ(0u, sb.st_flags);
 }
 
 /*