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[PATCH] xfsprogs: restrict platform_test_xfs_fd to regular files

To: xfs-oss <xfs@xxxxxxxxxxx>
Subject: [PATCH] xfsprogs: restrict platform_test_xfs_fd to regular files
From: Eric Sandeen <sandeen@xxxxxxxxxx>
Date: Tue, 08 Oct 2013 10:17:50 -0500
Delivered-to: xfs@xxxxxxxxxxx
User-agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.8; rv:17.0) Gecko/20130801 Thunderbird/17.0.8
If a special file (block, char, pipe etc) resides on an
xfs filesystem, platform_test_xfs_[fd|path] will return
true, but a subsequent xfsctl will fail, because the file
operations to support the xfs ioctls are not set up on such
files (see i_fop assignments in xfs_setup_inode()).

>From the xfsctl manpage it's pretty clear that these functions
are supposed to return true iff a subsequent xfsctl can be
handled, so it makes sense to exclude special files.

This was showing up in xfstest generic/306, which creates
the dev/null block device on an xfstest an tries to pwrite
to it with xfs_io - which emitted a warning when the xfsctl
trying to get geometry failed.

Signed-off-by: Eric Sandeen <sandeen@xxxxxxxxxx>
---

diff --git a/include/linux.h b/include/linux.h
index 5bb91cd..502fd1f 100644
--- a/include/linux.h
+++ b/include/linux.h
@@ -34,20 +34,38 @@ static __inline__ int xfsctl(const char *path, int fd, int 
cmd, void *p)
        return ioctl(fd, cmd, p);
 }
 
+/*
+ * platform_test_xfs_*() implies that xfsctl will succeed on the file;
+ * on Linux, at least, special files don't get xfs file ops,
+ * so return 0 for those
+ */
+
 static __inline__ int platform_test_xfs_fd(int fd)
 {
-       struct statfs buf;
-       if (fstatfs(fd, &buf) < 0)
+       struct statfs statfsbuf;
+       struct stat statbuf;
+
+       if (fstatfs(fd, &statfsbuf) < 0)
+               return 0;
+       if (fstat(fd, &statbuf) < 0)
                return 0;
-       return (buf.f_type == 0x58465342);      /* XFSB */
+       if (!S_ISREG(statbuf.st_mode) && !S_ISDIR(statbuf.st_mode))
+               return 0;
+       return (statfsbuf.f_type == 0x58465342);        /* XFSB */
 }
 
 static __inline__ int platform_test_xfs_path(const char *path)
 {
-       struct statfs buf;
-       if (statfs(path, &buf) < 0)
+       struct statfs statfsbuf;
+       struct stat statbuf;
+
+       if (statfs(path, &statfsbuf) < 0)
+               return 0;
+       if (stat(path, &statbuf) < 0)
+               return 0;
+       if (!S_ISREG(statbuf.st_mode) && !S_ISDIR(statbuf.st_mode))
                return 0;
-       return (buf.f_type == 0x58465342);      /* XFSB */
+       return (statfsbuf.f_type == 0x58465342);        /* XFSB */
 }
 
 static __inline__ int platform_fstatfs(int fd, struct statfs *buf)

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