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authorMark Johnston <markj@freebsd.org>2025-08-06 13:53:08 -0400
committerChristian Schoenebeck <qemu_oss@crudebyte.com>2025-09-18 21:21:29 +0200
commit6657f3bb55edba8f068cbc9ac40bb230ea1d7a09 (patch)
treec5d7a2bcc42ceb5aca6f17d48834ef705ab5aca4 /hw/9pfs/9p.c
parente7c1e8043a69c5a8efa39d4f9d111f7c72c076e6 (diff)
downloadfocaccia-qemu-6657f3bb55edba8f068cbc9ac40bb230ea1d7a09.tar.gz
focaccia-qemu-6657f3bb55edba8f068cbc9ac40bb230ea1d7a09.zip
9pfs: Add FreeBSD support
This is largely derived from existing Darwin support.  FreeBSD
apparently has better support for *at() system calls so doesn't require
workarounds for a missing mknodat().  The implementation has a couple of
warts however:
- The extattr(2) system calls don't support anything akin to
  XATTR_CREATE or XATTR_REPLACE, so a racy workaround is implemented.
- Attribute names cannot begin with "user." or "system." on ZFS.
  However FreeBSD's extattr(2) system calls support two dedicated
  namespaces for these two.  So "user." or "system." prefixes are
  trimmed off from attribute names and instead EXTATTR_NAMESPACE_USER or
  EXTATTR_NAMESPACE_SYSTEM are picked and passed to extattr system calls
  accordingly.

The 9pfs tests were verified to pass on the UFS, ZFS and tmpfs
filesystems.

Signed-off-by: Mark Johnston <markj@FreeBSD.org>
Link: https://lore.kernel.org/qemu-devel/aJOWhHB2p-fbueAm@nuc
Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com>
Diffstat (limited to 'hw/9pfs/9p.c')
-rw-r--r--hw/9pfs/9p.c16
1 files changed, 14 insertions, 2 deletions
diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c
index acfa7db4e1..bc4a016ee3 100644
--- a/hw/9pfs/9p.c
+++ b/hw/9pfs/9p.c
@@ -136,8 +136,10 @@ static int dotl_to_open_flags(int flags)
         { P9_DOTL_NONBLOCK, O_NONBLOCK } ,
         { P9_DOTL_DSYNC, O_DSYNC },
         { P9_DOTL_FASYNC, FASYNC },
-#ifndef CONFIG_DARWIN
+#if !defined(CONFIG_DARWIN) && !defined(CONFIG_FREEBSD)
         { P9_DOTL_NOATIME, O_NOATIME },
+#endif
+#ifndef CONFIG_DARWIN
         /*
          *  On Darwin, we could map to F_NOCACHE, which is
          *  similar, but doesn't quite have the same
@@ -3658,7 +3660,7 @@ static int v9fs_fill_statfs(V9fsState *s, V9fsPDU *pdu, struct statfs *stbuf)
     f_bavail = stbuf->f_bavail / bsize_factor;
     f_files  = stbuf->f_files;
     f_ffree  = stbuf->f_ffree;
-#ifdef CONFIG_DARWIN
+#if defined(CONFIG_DARWIN) || defined(CONFIG_FREEBSD)
     fsid_val = (unsigned int)stbuf->f_fsid.val[0] |
                (unsigned long long)stbuf->f_fsid.val[1] << 32;
     f_namelen = NAME_MAX;
@@ -4050,6 +4052,16 @@ out_nofid:
  * Linux guests.
  */
 #define P9_XATTR_SIZE_MAX 65536
+#elif defined(CONFIG_FREEBSD)
+/*
+ * FreeBSD similarly doesn't define a maximum xattr size, the limit is
+ * filesystem dependent.  On UFS filesystems it's 2 times the filesystem block
+ * size, typically 32KB.  On ZFS it depends on the value of the xattr property;
+ * with the default value there is no limit, and with xattr=sa it is 64KB.
+ *
+ * So, a limit of 64k seems reasonable here too.
+ */
+#define P9_XATTR_SIZE_MAX 65536
 #else
 #error Missing definition for P9_XATTR_SIZE_MAX for this host system
 #endif