linux/fs/compat.c, branch v2.6.31-rc2

trivial: fix comment typo in fs/compat.c

2009-06-12T16:01:44Z

Fix a typo in fs/compat.c Signed-off-by: Nikanth Karthikesan Signed-off-by: Jiri Kosina

Push BKL into do_mount()

2009-06-12T01:36:08Z

Signed-off-by: Al Viro

CRED: Rename cred_exec_mutex to reflect that it's a guard against ptrace

2009-05-10T22:15:36Z

Rename cred_exec_mutex to reflect that it's a guard against foreign intervention on a process's credential state, such as is made by ptrace(). The attachment of a debugger to a process affects execve()'s calculation of the new credential state - _and_ also setprocattr()'s calculation of that state. Signed-off-by: David Howells Signed-off-by: James Morris

do_execve() must not clear fs->in_exec if it was set by another thread

2009-04-24T14:39:45Z

If do_execve() fails after check_unsafe_exec(), it clears fs->in_exec unconditionally. This is wrong if we race with our sub-thread which also does do_execve: Two threads T1 and T2 and another process P, all share the same ->fs. T1 starts do_execve(BAD_FILE). It calls check_unsafe_exec(), since ->fs is shared, we set LSM_UNSAFE but not ->in_exec. P exits and decrements fs->users. T2 starts do_execve(), calls check_unsafe_exec(), now ->fs is not shared, we set fs->in_exec. T1 continues, open_exec(BAD_FILE) fails, we clear ->in_exec and return to the user-space. T1 does clone(CLONE_FS /* without CLONE_THREAD */). T2 continues without LSM_UNSAFE_SHARE while ->fs is shared with another process. Change check_unsafe_exec() to return res = 1 if we set ->in_exec, and change do_execve() to clear ->in_exec depending on res. When do_execve() suceeds, it is safe to clear ->in_exec unconditionally. It can be set only if we don't share ->fs with another process, and since we already killed all sub-threads either ->in_exec == 0 or we are the only user of this ->fs. Also, we do not need fs->lock to clear fs->in_exec. Signed-off-by: Oleg Nesterov Acked-by: Roland McGrath Acked-by: Hugh Dickins Signed-off-by: Linus Torvalds

kill vfs_stat_fd / vfs_lstat_fd

2009-04-21T03:02:52Z

There's really no reason to keep vfs_stat_fd and vfs_lstat_fd with Oleg's vfs_fstatat. Use vfs_fstatat for the few cases having the directory fd, and switch all others to vfs_stat / vfs_lstat. Reviewed-by: Christoph Hellwig Signed-off-by: Al Viro

Separate out common fstatat code into vfs_fstatat

2009-04-21T03:02:51Z

This is a version incorporating Christoph's suggestion. Separate out common *fstatat functionality into a single function instead of duplicating it all over the code. Signed-off-by: Oleg Drokin Signed-off-by: Al Viro

Make non-compat preadv/pwritev use native register size

2009-04-04T21:20:34Z

Instead of always splitting the file offset into 32-bit 'high' and 'low' parts, just split them into the largest natural word-size - which in C terms is 'unsigned long'. This allows 64-bit architectures to avoid the unnecessary 32-bit shifting and masking for native format (while the compat interfaces will obviously always have to do it). This also changes the order of 'high' and 'low' to be "low first". Why? Because when we have it like this, the 64-bit system calls now don't use the "pos_high" argument at all, and it makes more sense for the native system call to simply match the user-mode prototype. This results in a much more natural calling convention, and allows the compiler to generate much more straightforward code. On x86-64, we now generate testq %rcx, %rcx # pos_l js .L122 #, movq %rcx, -48(%rbp) # pos_l, pos from the C source loff_t pos = pos_from_hilo(pos_h, pos_l); ... if (pos < 0) return -EINVAL; and the 'pos_h' register isn't even touched. It used to generate code like mov %r8d, %r8d # pos_low, pos_low salq $32, %rcx #, tmp71 movq %r8, %rax # pos_low, pos.386 orq %rcx, %rax # tmp71, pos.386 js .L122 #, movq %rax, -48(%rbp) # pos.386, pos which isn't _that_ horrible, but it does show how the natural word size is just a more sensible interface (same arguments will hold in the user level glibc wrapper function, of course, so the kernel side is just half of the equation!) Note: in all cases the user code wrapper can again be the same. You can just do #define HALF_BITS (sizeof(unsigned long)*4) __syscall(PWRITEV, fd, iov, count, offset, (offset >> HALF_BITS) >> HALF_BITS); or something like that. That way the user mode wrapper will also be nicely passing in a zero (it won't actually have to do the shifts, the compiler will understand what is going on) for the last argument. And that is a good idea, even if nobody will necessarily ever care: if we ever do move to a 128-bit lloff_t, this particular system call might be left alone. Of course, that will be the least of our worries if we really ever need to care, so this may not be worth really caring about. [ Fixed for lost 'loff_t' cast noticed by Andrew Morton ] Acked-by: Gerd Hoffmann Cc: H. Peter Anvin Cc: Andrew Morton Cc: linux-api@vger.kernel.org Cc: linux-arch@vger.kernel.org Cc: Ingo Molnar Cc: Ralf Baechle > Cc: Al Viro Signed-off-by: Linus Torvalds

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6

2009-04-03T04:09:10Z

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6: Remove two unneeded exports and make two symbols static in fs/mpage.c Cleanup after commit 585d3bc06f4ca57f975a5a1f698f65a45ea66225 Trim includes of fdtable.h Don't crap into descriptor table in binfmt_som Trim includes in binfmt_elf Don't mess with descriptor table in load_elf_binary() Get rid of indirect include of fs_struct.h New helper - current_umask() check_unsafe_exec() doesn't care about signal handlers sharing New locking/refcounting for fs_struct Take fs_struct handling to new file (fs/fs_struct.c) Get rid of bumping fs_struct refcount in pivot_root(2) Kill unsharing fs_struct in __set_personality()

preadv/pwritev: switch compat readv/preadv/writev/pwritev from fget to fget_light

2009-04-03T02:05:08Z

Signed-off-by: Gerd Hoffmann Cc: Arnd Bergmann Cc: Al Viro Cc: Cc: Cc: Ralf Baechle Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

preadv/pwritev: Add preadv and pwritev system calls.

2009-04-03T02:05:08Z

This patch adds preadv and pwritev system calls. These syscalls are a pretty straightforward combination of pread and readv (same for write). They are quite useful for doing vectored I/O in threaded applications. Using lseek+readv instead opens race windows you'll have to plug with locking. Other systems have such system calls too, for example NetBSD, check here: http://www.daemon-systems.org/man/preadv.2.html The application-visible interface provided by glibc should look like this to be compatible to the existing implementations in the *BSD family: ssize_t preadv(int d, const struct iovec *iov, int iovcnt, off_t offset); ssize_t pwritev(int d, const struct iovec *iov, int iovcnt, off_t offset); This prototype has one problem though: On 32bit archs is the (64bit) offset argument unaligned, which the syscall ABI of several archs doesn't allow to do. At least s390 needs a wrapper in glibc to handle this. As we'll need a wrappers in glibc anyway I've decided to push problem to glibc entriely and use a syscall prototype which works without arch-specific wrappers inside the kernel: The offset argument is explicitly splitted into two 32bit values. The patch sports the actual system call implementation and the windup in the x86 system call tables. Other archs follow as separate patches. Signed-off-by: Gerd Hoffmann Cc: Arnd Bergmann Cc: Al Viro Cc: Cc: Cc: Ralf Baechle Cc: Ingo Molnar Cc: Thomas Gleixner Cc: "H. Peter Anvin" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds