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  1. 04 11月, 2014 32 次提交
  3. 01 11月, 2014 1 次提交
  5. 31 10月, 2014 3 次提交
    • D
      Return short read or 0 at end of a raw device, not EIO · b2de525f
      由 David Jeffery 提交于 
      Author: David Jeffery <djeffery@redhat.com>
Changes to the basic direct I/O code have broken the raw driver when reading
to the end of a raw device.  Instead of returning a short read for a read that
extends partially beyond the device's end or 0 when at the end of the device,
these reads now return EIO.

The raw driver needs the same end of device handling as was added for normal
block devices.  Using blkdev_read_iter, which has the needed size checks,
prevents the EIO conditions at the end of the device.
Signed-off-by: NDavid Jeffery <djeffery@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
      b2de525f
    • A
      isofs: don't bother with ->d_op for normal case · b0afd8e5
      由 Al Viro 提交于 
      we only need it for joliet and case-insensitive mounts
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
      b0afd8e5
    • E
      fs: allow open(dir, O_TMPFILE|..., 0) with mode 0 · 69a91c23
      由 Eric Rannaud 提交于 
      The man page for open(2) indicates that when O_CREAT is specified, the
'mode' argument applies only to future accesses to the file:

	Note that this mode applies only to future accesses of the newly
	created file; the open() call that creates a read-only file
	may well return a read/write file descriptor.

The man page for open(2) implies that 'mode' is treated identically by
O_CREAT and O_TMPFILE.

O_TMPFILE, however, behaves differently:

	int fd = open("/tmp", O_TMPFILE | O_RDWR, 0);
	assert(fd == -1);
	assert(errno == EACCES);

	int fd = open("/tmp", O_TMPFILE | O_RDWR, 0600);
	assert(fd > 0);

For O_CREAT, do_last() sets acc_mode to MAY_OPEN only:

	if (*opened & FILE_CREATED) {
		/* Don't check for write permission, don't truncate */
		open_flag &= ~O_TRUNC;
		will_truncate = false;
		acc_mode = MAY_OPEN;
		path_to_nameidata(path, nd);
		goto finish_open_created;
	}

But for O_TMPFILE, do_tmpfile() passes the full op->acc_mode to
may_open().

This patch lines up the behavior of O_TMPFILE with O_CREAT. After the
inode is created, may_open() is called with acc_mode = MAY_OPEN, in
do_tmpfile().

A different, but related glibc bug revealed the discrepancy:
https://sourceware.org/bugzilla/show_bug.cgi?id=17523

The glibc lazily loads the 'mode' argument of open() and openat() using
va_arg() only if O_CREAT is present in 'flags' (to support both the 2
argument and the 3 argument forms of open; same idea for openat()).
However, the glibc ignores the 'mode' argument if O_TMPFILE is in
'flags'.

On x86_64, for open(), it magically works anyway, as 'mode' is in
RDX when entering open(), and is still in RDX on SYSCALL, which is where
the kernel looks for the 3rd argument of a syscall.

But openat() is not quite so lucky: 'mode' is in RCX when entering the
glibc wrapper for openat(), while the kernel looks for the 4th argument
of a syscall in R10. Indeed, the syscall calling convention differs from
the regular calling convention in this respect on x86_64. So the kernel
sees mode = 0 when trying to use glibc openat() with O_TMPFILE, and
fails with EACCES.
Signed-off-by: NEric Rannaud <e@nanocritical.com>
Acked-by: NAndy Lutomirski <luto@amacapital.net>
Cc: stable@vger.kernel.org
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      69a91c23
  7. 30 10月, 2014 4 次提交