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authorMateusz Guzik <mjg@FreeBSD.org>2020-01-17 14:42:25 +0000
committerMateusz Guzik <mjg@FreeBSD.org>2020-01-17 14:42:25 +0000
commitd3cc535474a0df422a6928615dcb3afe46af253f (patch)
tree11cb0eec9ca78180b12950b20a7413ec8598b87d /sys/sys/mount.h
parent360af171b3dde5cd316fc76068c0d31972bef1d6 (diff)
downloadsrc-d3cc535474a0df422a6928615dcb3afe46af253f.tar.gz
src-d3cc535474a0df422a6928615dcb3afe46af253f.zip
vfs: provide F_ISUNIONSTACK as a kludge for libc
Prior to introduction of this op libc's readdir would call fstatfs(2), in effect unnecessarily copying kilobytes of data just to check fs name and a mount flag. Reviewed by: kib (previous version) Differential Revision: https://reviews.freebsd.org/D23162
Notes
Notes: svn path=/head/; revision=356830
Diffstat (limited to 'sys/sys/mount.h')
-rw-r--r--sys/sys/mount.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/sys/sys/mount.h b/sys/sys/mount.h
index 0bf8f2e28c74..6c23cb25c352 100644
--- a/sys/sys/mount.h
+++ b/sys/sys/mount.h
@@ -414,6 +414,7 @@ void __mnt_vnode_markerfree_lazy(struct vnode **mvp, struct mount *mp);
#define MNTK_USES_BCACHE 0x00004000 /* FS uses the buffer cache. */
#define MNTK_TEXT_REFS 0x00008000 /* Keep use ref for text */
#define MNTK_VMSETSIZE_BUG 0x00010000
+#define MNTK_UNIONFS 0x00020000 /* A hack for F_ISUNIONSTACK */
#define MNTK_NOASYNC 0x00800000 /* disable async */
#define MNTK_UNMOUNT 0x01000000 /* unmount in progress */
#define MNTK_MWAIT 0x02000000 /* waiting for unmount to finish */