fstat patch (64-bit os, zfs or devfs)
Andriy Gapon
avg at freebsd.org
Fri Jun 12 16:50:45 UTC 2009
What do you think about the following change?
commit c6d04723027dbc493376b6fd058bd7875ec8a888
Author: Andriy Gapon <avg at icyb.net.ua>
Date: Fri Jun 12 19:16:45 2009 +0300
fstat: fix fsid comparison when executed on a file on 64-bit system
This affects only fstat on zfs and devfs, only on 64-bit systems
and only when fsid is greater than 2^31 - 1.
When fstat examines a file via stat(2) it takes uint32_t st_dev
and assigns to (signed) (64-bit) long fsid, this results in
a positive value.
When fstat examines opened files it takes int32_t f_fsid.val[0]
and assigns to (signed) (64-bit) long fsid, this results in
a negative value.
So, while initially st_dev and f_fsid.val[0] have the same bit
values they get promoted to different 64-bit values because
of the signed-vs-unsigned difference.
A fix is to use "more natural" positive numbers by introducing
intermediate unsigned cast for f_fsid.val[0].
diff --git a/usr.bin/fstat/fstat.c b/usr.bin/fstat/fstat.c
index 0907c49..dc728e5 100644
--- a/usr.bin/fstat/fstat.c
+++ b/usr.bin/fstat/fstat.c
@@ -649,7 +649,7 @@ devfs_filestat(struct vnode *vp, struct filestat *fsp)
(void *)devfs_dirent.de_vnode, Pid);
return 0;
}
- fsp->fsid = (long)mount.mnt_stat.f_fsid.val[0];
+ fsp->fsid = (long)(uint32_t)mount.mnt_stat.f_fsid.val[0];
fsp->fileid = devfs_dirent.de_inode;
fsp->mode = (devfs_dirent.de_mode & ~S_IFMT) | S_IFCHR;
fsp->size = 0;
diff --git a/usr.bin/fstat/zfs.c b/usr.bin/fstat/zfs.c
index f611b1c..f654e79 100644
--- a/usr.bin/fstat/zfs.c
+++ b/usr.bin/fstat/zfs.c
@@ -117,7 +117,7 @@ zfs_filestat(struct vnode *vp, struct filestat *fsp)
goto bad;
}
- fsp->fsid = (long)mount.mnt_stat.f_fsid.val[0];
+ fsp->fsid = (long)(uint32_t)mount.mnt_stat.f_fsid.val[0];
fsp->fileid = *zid;
/*
* XXX: Shows up wrong in output, but UFS has this error too. Could
--
Andriy Gapon
More information about the freebsd-current
mailing list