[PATCH] fcntl: allow to set O_DIRECT flag on pipe

[PATCH] fcntl: allow to set O_DIRECT flag on pipe

[Stanislav Kinsburskiy]

With packetized mode for pipes, it's not possible to set O_DIRECT on pipe file
via sys_fcntl, because of unsupported (by pipes) sanity checks.
Ability to set this flag will be used by CRIU to migrate packetized pipes.

Signed-off-by: Stanislav Kinsburskiy <skinsbursky@virtuozzo.com>
---
 fs/fcntl.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/fcntl.c b/fs/fcntl.c
index ee85cd4..4463a87 100644
--- a/fs/fcntl.c
+++ b/fs/fcntl.c
@@ -51,7 +51,8 @@ static int setfl(int fd, struct file * filp, unsigned long arg)
 	       if (arg & O_NDELAY)
 		   arg |= O_NONBLOCK;
 
-	if (arg & O_DIRECT) {
+	/* Pipe packetized mode is controlled by O_DIRECT flag */
+	if (!IS_FIFO(f->f_mode) && (arg & O_DIRECT)) {
 		if (!filp->f_mapping || !filp->f_mapping->a_ops ||
 			!filp->f_mapping->a_ops->direct_IO)
 				return -EINVAL;

Re: [PATCH] fcntl: allow to set O_DIRECT flag on pipe

[kbuild test robot]

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Hi Stanislav,

[auto build test ERROR on v4.4-rc5]
[also build test ERROR on next-20151215]

url:    https://github.com/0day-ci/linux/commits/Stanislav-Kinsburskiy/fcntl-allow-to-set-O_DIRECT-flag-on-pipe/20151216-000234
config: x86_64-randconfig-x011-12141150 (attached as .config)
reproduce:
        # save the attached .config to linux build tree
        make ARCH=x86_64 

All errors (new ones prefixed by >>):

   fs/fcntl.c: In function 'setfl':
>> fs/fcntl.c:55:7: error: implicit declaration of function 'IS_FIFO' [-Werror=implicit-function-declaration]
     if (!IS_FIFO(f->f_mode) && (arg & O_DIRECT)) {
          ^
>> fs/fcntl.c:55:15: error: 'f' undeclared (first use in this function)
     if (!IS_FIFO(f->f_mode) && (arg & O_DIRECT)) {
                  ^
   fs/fcntl.c:55:15: note: each undeclared identifier is reported only once for each function it appears in
   cc1: some warnings being treated as errors

vim +/IS_FIFO +55 fs/fcntl.c

    49		/* required for strict SunOS emulation */
    50		if (O_NONBLOCK != O_NDELAY)
    51		       if (arg & O_NDELAY)
    52			   arg |= O_NONBLOCK;
    53	
    54		/* Pipe packetized mode is controlled by O_DIRECT flag */
  > 55		if (!IS_FIFO(f->f_mode) && (arg & O_DIRECT)) {
    56			if (!filp->f_mapping || !filp->f_mapping->a_ops ||
    57				!filp->f_mapping->a_ops->direct_IO)
    58					return -EINVAL;

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

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Re: [PATCH] fcntl: allow to set O_DIRECT flag on pipe

[kbuild test robot]

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Hi Stanislav,

[auto build test WARNING on v4.4-rc5]
[also build test WARNING on next-20151215]

url:    https://github.com/0day-ci/linux/commits/Stanislav-Kinsburskiy/fcntl-allow-to-set-O_DIRECT-flag-on-pipe/20151216-000234
config: i386-randconfig-x009-12141102 (attached as .config)
reproduce:
        # save the attached .config to linux build tree
        make ARCH=i386 

All warnings (new ones prefixed by >>):

   In file included from include/uapi/linux/stddef.h:1:0,
                    from include/linux/stddef.h:4,
                    from include/uapi/linux/posix_types.h:4,
                    from include/uapi/linux/types.h:13,
                    from include/linux/types.h:5,
                    from include/linux/syscalls.h:70,
                    from fs/fcntl.c:7:
   fs/fcntl.c: In function 'setfl':
   fs/fcntl.c:55:7: error: implicit declaration of function 'IS_FIFO' [-Werror=implicit-function-declaration]
     if (!IS_FIFO(f->f_mode) && (arg & O_DIRECT)) {
          ^
   include/linux/compiler.h:147:28: note: in definition of macro '__trace_if'
     if (__builtin_constant_p((cond)) ? !!(cond) :   \
                               ^
>> fs/fcntl.c:55:2: note: in expansion of macro 'if'
     if (!IS_FIFO(f->f_mode) && (arg & O_DIRECT)) {
     ^
   fs/fcntl.c:55:15: error: 'f' undeclared (first use in this function)
     if (!IS_FIFO(f->f_mode) && (arg & O_DIRECT)) {
                  ^
   include/linux/compiler.h:147:28: note: in definition of macro '__trace_if'
     if (__builtin_constant_p((cond)) ? !!(cond) :   \
                               ^
>> fs/fcntl.c:55:2: note: in expansion of macro 'if'
     if (!IS_FIFO(f->f_mode) && (arg & O_DIRECT)) {
     ^
   fs/fcntl.c:55:15: note: each undeclared identifier is reported only once for each function it appears in
     if (!IS_FIFO(f->f_mode) && (arg & O_DIRECT)) {
                  ^
   include/linux/compiler.h:147:28: note: in definition of macro '__trace_if'
     if (__builtin_constant_p((cond)) ? !!(cond) :   \
                               ^
>> fs/fcntl.c:55:2: note: in expansion of macro 'if'
     if (!IS_FIFO(f->f_mode) && (arg & O_DIRECT)) {
     ^
   cc1: some warnings being treated as errors

vim +/if +55 fs/fcntl.c

     1	/*
     2	 *  linux/fs/fcntl.c
     3	 *
     4	 *  Copyright (C) 1991, 1992  Linus Torvalds
     5	 */
     6	
   > 7	#include <linux/syscalls.h>
     8	#include <linux/init.h>
     9	#include <linux/mm.h>
    10	#include <linux/fs.h>
    11	#include <linux/file.h>
    12	#include <linux/fdtable.h>
    13	#include <linux/capability.h>
    14	#include <linux/dnotify.h>
    15	#include <linux/slab.h>
    16	#include <linux/module.h>
    17	#include <linux/pipe_fs_i.h>
    18	#include <linux/security.h>
    19	#include <linux/ptrace.h>
    20	#include <linux/signal.h>
    21	#include <linux/rcupdate.h>
    22	#include <linux/pid_namespace.h>
    23	#include <linux/user_namespace.h>
    24	#include <linux/shmem_fs.h>
    25	
    26	#include <asm/poll.h>
    27	#include <asm/siginfo.h>
    28	#include <asm/uaccess.h>
    29	
    30	#define SETFL_MASK (O_APPEND | O_NONBLOCK | O_NDELAY | O_DIRECT | O_NOATIME)
    31	
    32	static int setfl(int fd, struct file * filp, unsigned long arg)
    33	{
    34		struct inode * inode = file_inode(filp);
    35		int error = 0;
    36	
    37		/*
    38		 * O_APPEND cannot be cleared if the file is marked as append-only
    39		 * and the file is open for write.
    40		 */
    41		if (((arg ^ filp->f_flags) & O_APPEND) && IS_APPEND(inode))
    42			return -EPERM;
    43	
    44		/* O_NOATIME can only be set by the owner or superuser */
    45		if ((arg & O_NOATIME) && !(filp->f_flags & O_NOATIME))
    46			if (!inode_owner_or_capable(inode))
    47				return -EPERM;
    48	
    49		/* required for strict SunOS emulation */
    50		if (O_NONBLOCK != O_NDELAY)
    51		       if (arg & O_NDELAY)
    52			   arg |= O_NONBLOCK;
    53	
    54		/* Pipe packetized mode is controlled by O_DIRECT flag */
  > 55		if (!IS_FIFO(f->f_mode) && (arg & O_DIRECT)) {
    56			if (!filp->f_mapping || !filp->f_mapping->a_ops ||
    57				!filp->f_mapping->a_ops->direct_IO)
    58					return -EINVAL;

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

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