user/sven/linux.git/fs/read_write.c, branch v3.15.6

Merge branch 'compat' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

2014-03-31T21:32:17Z

Pull s390 compat wrapper rework from Heiko Carstens: "S390 compat system call wrapper simplification work. The intention of this work is to get rid of all hand written assembly compat system call wrappers on s390, which perform proper sign or zero extension, or pointer conversion of compat system call parameters. Instead all of this should be done with C code eg by using Al's COMPAT_SYSCALL_DEFINEx() macro. Therefore all common code and s390 specific compat system calls have been converted to the COMPAT_SYSCALL_DEFINEx() macro. In order to generate correct code all compat system calls may only have eg compat_ulong_t parameters, but no unsigned long parameters. Those patches which change parameter types from unsigned long to compat_ulong_t parameters are separate in this series, but shouldn't cause any harm. The only compat system calls which intentionally have 64 bit parameters (preadv64 and pwritev64) in support of the x86/32 ABI haven't been changed, but are now only available if an architecture defines __ARCH_WANT_COMPAT_SYS_PREADV64/PWRITEV64. System calls which do not have a compat variant but still need proper zero extension on s390, like eg "long sys_brk(unsigned long brk)" will get a proper wrapper function with the new s390 specific COMPAT_SYSCALL_WRAPx() macro: COMPAT_SYSCALL_WRAP1(brk, unsigned long, brk); which generates the following code (simplified): asmlinkage long sys_brk(unsigned long brk); asmlinkage long compat_sys_brk(long brk) { return sys_brk((u32)brk); } Given that the C file which contains all the COMPAT_SYSCALL_WRAP lines includes both linux/syscall.h and linux/compat.h, it will generate build errors, if the declaration of sys_brk() doesn't match, or if there exists a non-matching compat_sys_brk() declaration. In addition this will intentionally result in a link error if somewhere else a compat_sys_brk() function exists, which probably should have been used instead. Two more BUILD_BUG_ONs make sure the size and type of each compat syscall parameter can be handled correctly with the s390 specific macros. I converted the compat system calls step by step to verify the generated code is correct and matches the previous code. In fact it did not always match, however that was always a bug in the hand written asm code. In result we get less code, less bugs, and much more sanity checking" * 'compat' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (44 commits) s390/compat: add copyright statement compat: include linux/unistd.h within linux/compat.h s390/compat: get rid of compat wrapper assembly code s390/compat: build error for large compat syscall args mm/compat: convert to COMPAT_SYSCALL_DEFINE with changing parameter types kexec/compat: convert to COMPAT_SYSCALL_DEFINE with changing parameter types net/compat: convert to COMPAT_SYSCALL_DEFINE with changing parameter types ipc/compat: convert to COMPAT_SYSCALL_DEFINE with changing parameter types fs/compat: convert to COMPAT_SYSCALL_DEFINE with changing parameter types ipc/compat: convert to COMPAT_SYSCALL_DEFINE fs/compat: convert to COMPAT_SYSCALL_DEFINE security/compat: convert to COMPAT_SYSCALL_DEFINE mm/compat: convert to COMPAT_SYSCALL_DEFINE net/compat: convert to COMPAT_SYSCALL_DEFINE kernel/compat: convert to COMPAT_SYSCALL_DEFINE fs/compat: optional preadv64/pwrite64 compat system calls ipc/compat_sys_msgrcv: change msgtyp type from long to compat_long_t s390/compat: partial parameter conversion within syscall wrappers s390/compat: automatic zero, sign and pointer conversion of syscalls s390/compat: add sync_file_range and fallocate compat syscalls ...

vfs: atomic f_pos access in llseek()

2014-03-23T04:03:12Z

Commit 9c225f2655e36a4 ("vfs: atomic f_pos accesses as per POSIX") changed several system calls to use fdget_pos() instead of fdget(), but missed sys_llseek(). Fix it. Signed-off-by: Eric Biggers Signed-off-by: Al Viro

get rid of fget_light()

2014-03-10T15:44:42Z

instead of returning the flags by reference, we can just have the low-level primitive return those in lower bits of unsigned long, with struct file * derived from the rest. Signed-off-by: Al Viro

vfs: atomic f_pos accesses as per POSIX

2014-03-10T15:44:41Z

Our write() system call has always been atomic in the sense that you get the expected thread-safe contiguous write, but we haven't actually guaranteed that concurrent writes are serialized wrt f_pos accesses, so threads (or processes) that share a file descriptor and use "write()" concurrently would quite likely overwrite each others data. This violates POSIX.1-2008/SUSv4 Section XSI 2.9.7 that says: "2.9.7 Thread Interactions with Regular File Operations All of the following functions shall be atomic with respect to each other in the effects specified in POSIX.1-2008 when they operate on regular files or symbolic links: [...]" and one of the effects is the file position update. This unprotected file position behavior is not new behavior, and nobody has ever cared. Until now. Yongzhi Pan reported unexpected behavior to Michael Kerrisk that was due to this. This resolves the issue with a f_pos-specific lock that is taken by read/write/lseek on file descriptors that may be shared across threads or processes. Reported-by: Yongzhi Pan Reported-by: Michael Kerrisk Cc: Al Viro Signed-off-by: Linus Torvalds Signed-off-by: Al Viro

fs/compat: optional preadv64/pwrite64 compat system calls

2014-03-06T14:35:09Z

The preadv64/pwrite64 have been implemented for the x32 ABI, in order to allow passing 64 bit arguments from user space without splitting them into two 32 bit parameters, like it would be necessary for usual compat tasks. Howevert these two system calls are only being used for the x32 ABI, so add __ARCH_WANT_COMPAT defines for these two compat syscalls and make these two only visible for x86. Signed-off-by: Heiko Carstens

fs/compat: fix parameter handling for compat readv/writev syscalls

2014-01-30T00:22:39Z

We got a report that the pwritev syscall does not work correctly in compat mode on s390. It turned out that with commit 72ec35163f9f ("switch compat readv/writev variants to COMPAT_SYSCALL_DEFINE") we lost the zero extension of a couple of syscall parameters because the some parameter types haven't been converted from unsigned long to compat_ulong_t. This is needed for architectures where the ABI requires that the caller of a function performed zero and/or sign extension to 64 bit of all parameters. Signed-off-by: Heiko Carstens Cc: Al Viro Cc: Ingo Molnar Cc: "H. Peter Anvin" Cc: Hendrik Brueckner Cc: Martin Schwidefsky Cc: [v3.10+] Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

fs/read_write.c:compat_readv(): remove bogus area verify

2014-01-22T00:19:42Z

The compat_do_readv_writev() function was doing a verify_area on the incoming iov, but the nr_segs value is not checked. If someone passes in a -1 for nr_segs, for instance, the function should return an EINVAL. However, it returns a EFAULT because the verify_area fails because it is checking an array of size MAX_UINT. The check is bogus, anyway, because the next check, compat_rw_copy_check_uvector(), will do all the necessary checking, anyway. The non-compat do_readv_writev() function doesn't do this check, so I think it's safe to just remove the code. Signed-off-by: Corey Minyard Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

file->f_op is never NULL...

2013-10-25T03:34:54Z

Signed-off-by: Al Viro

aio: Kill aio_rw_vect_retry()

2013-07-30T15:53:12Z

This code doesn't serve any purpose anymore, since the aio retry infrastructure has been removed. This change should be safe because aio_read/write are also used for synchronous IO, and called from do_sync_read()/do_sync_write() - and there's no looping done in the sync case (the read and write syscalls). Signed-off-by: Kent Overstreet Cc: Zach Brown Cc: Felipe Balbi Cc: Greg Kroah-Hartman Cc: Mark Fasheh Cc: Joel Becker Cc: Rusty Russell Cc: Jens Axboe Cc: Asai Thambi S P Cc: Selvan Mani Cc: Sam Bradshaw Cc: Jeff Moyer Cc: Al Viro Cc: Benjamin LaHaise Signed-off-by: Benjamin LaHaise

vfs: export lseek_execute() to modules

2013-07-03T12:23:27Z

For those file systems(btrfs/ext4/ocfs2/tmpfs) that support SEEK_DATA/SEEK_HOLE functions, we end up handling the similar matter in lseek_execute() to update the current file offset to the desired offset if it is valid, ceph also does the simliar things at ceph_llseek(). To reduce the duplications, this patch make lseek_execute() public accessible so that we can call it directly from the underlying file systems. Thanks Dave Chinner for this suggestion. [AV: call it vfs_setpos(), don't bring the removed 'inode' argument back] v2->v1: - Add kernel-doc comments for lseek_execute() - Call lseek_execute() in ceph->llseek() Signed-off-by: Jie Liu Cc: Dave Chinner Cc: Al Viro Cc: Andi Kleen Cc: Andrew Morton Cc: Christoph Hellwig Cc: Chris Mason Cc: Josef Bacik Cc: Ben Myers Cc: Ted Tso Cc: Hugh Dickins Cc: Mark Fasheh Cc: Joel Becker Cc: Sage Weil Signed-off-by: Al Viro