Make ufs return f_fsid info for statfs(2).
Signed-off-by: NColy Li <coly.li@suse.de>
Cc: Evgeniy Dushistov <dushistov@mail.ru>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Make sysv file system return f_fsid info for statfs(2).
Signed-off-by: NColy Li <coly.li@suse.de>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Make squashfs return f_fsid info for statfs(2).
Signed-off-by: NColy Li <coly.li@suse.de>
Cc: Phillip Lougher <phillip@lougher.demon.co.uk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Make reiserfs3 return f_fsid info for statfs(2).  By Andreas' suggestion,
this patch populates a persistent f_fsid between boots/mounts with help of
on-disk uuid record.

Randy Dunlap reported a compiling error from v2 patch like:
    fs/built-in.o: In function `reiserfs_statfs':
    super.c:(.text+0x7332b): undefined reference to `crc32_le'
    super.c:(.text+0x7333f): undefined reference to `crc32_le'
Also he provided helpful solution to fix this error. The modification of v3
patch is based on Randy's suggestion, add 'select CRC32' in fs/reiserfs/Kconfig.
Signed-off-by: NColy Li <coly.li@suse.de>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Make qnx4 file system return f_fsid info for statfs(2).
Signed-off-by: NColy Li <coly.li@suse.de>
Acked-by: NAnders Larsen <al@alarsen.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Make omfs return f_fsid info for statfs(2).
Signed-off-by: NColy Li <coly.li@suse.de>
Acked-by: NBob Copeland <me@bobcopeland.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Make minix file system return f_fsid info for statfs(2).
Signed-off-by: NColy Li <coly.li@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Make isofs return f_fsid info for statfs(2).
Signed-off-by: NColy Li <coly.li@suse.de>
Cc: Jan Kara <jack@ucw.cz>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Make hpfs return f_fsid info for statfs(2).
Signed-off-by: NColy Li <coly.li@suse.de>
Cc: Mikulas Patocka <mikulas@artax.karlin.mff.cuni.cz>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Make hfsplus return f_fsid info for statfs(2).
Signed-off-by: NColy Li <coly.li@suse.de>
Cc: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Make hfs return f_fsid info for statfs(2).
Signed-off-by: NColy Li <coly.li@suse.de>
Cc: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Make fat return f_fsid info for statfs(2).
Signed-off-by: NColy Li <coly.li@suse.de>
Acked-by: NOGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Make efs return f_fsid info for statfs(2), and do a little variable
renaming in efs_statfs().
Signed-off-by: NColy Li <coly.li@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Make cramfs return f_fsid info for statfs(2).
Signed-off-by: NColy Li <coly.li@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Make befs return f_fsid info for statfs(2).
Signed-off-by: NColy Li <coly.li@suse.de>
Cc: Sergey S. Kostyliov <rathamahata@php4.ru>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Make affs return f_fsid info for statfs(2).
Signed-off-by: NColy Li <coly.li@suse.de>
Cc: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Currently many file systems in Linux kernel do not return f_fsid in statfs
info, the value is set as 0 in vfs layer.  Anyway, in some conditions,
f_fsid from statfs(2) is useful, especially being used as (f_fsid, ino)
pair to uniquely identify a file.

Basic idea of the patches is generating a unique fs ID by
huge_encode_dev(sb->s_bdev->bd_dev) during file system mounting life time
(no endian consistent issue).  sb is a point of struct super_block of
current mounted file system being accessed by statfs(2).

This patch:

Make adfs return f_fsid info for statfs(2), and do a little variable
renaming in adfs_statfs().
Signed-off-by: NColy Li <coly.li@suse.de>
Cc: Roman Zippel <zippel@linux-m68k.org>
Cc: "Sergey S. Kostyliov" <rathamahata@php4.ru>
Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Cc: Mikulas Patocka <mikulas@artax.karlin.mff.cuni.cz>
Cc: Dave Kleikamp <shaggy@austin.ibm.com>
Cc: Bob Copeland <me@bobcopeland.com>
Cc: Anders Larsen <al@alarsen.net>
Cc: Phillip Lougher <phillip@lougher.demon.co.uk>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Evgeniy Dushistov <dushistov@mail.ru>
Cc: Jan Kara <jack@suse.cz>
Cc: Andreas Dilger <adilger@sun.com>
Cc: Jamie Lokier <jamie@shareable.org>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: <linux-api@vger.kernel.org>
Cc: <linux-arch@vger.kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

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: NGerd Hoffmann <kraxel@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: <linux-api@vger.kernel.org>
Cc: <linux-arch@vger.kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Factor out some code from compat_sys_writev() which can be shared with the
upcoming compat_sys_pwritev().
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: <linux-api@vger.kernel.org>
Cc: <linux-arch@vger.kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch series:

Implement the preadv() and pwritev() syscalls.  *BSD has this syscall for
quite some time.

Test code:

#if 0
set -x
gcc -Wall -O2 -o preadv $0
exit 0
#endif
/*
 * preadv demo / test
 *
 * (c) 2008 Gerd Hoffmann <kraxel@redhat.com>
 *
 * build with "sh $thisfile"
 */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <inttypes.h>
#include <sys/uio.h>

/* ----------------------------------------------------------------- */
/* syscall windup                                                    */

#include <sys/syscall.h>
#if 0
/* WARNING: Be sure you know what you are doing if you enable this.
 * linux syscall code isn't upstream yet, syscall numbers are subject
 * to change */
# ifndef __NR_preadv
#  ifdef __i386__
#   define __NR_preadv  333
#   define __NR_pwritev 334
#  endif
#  ifdef __x86_64__
#   define __NR_preadv  295
#   define __NR_pwritev 296
#  endif
# endif
#endif
#ifndef __NR_preadv
# error preadv/pwritev syscall numbers are unknown
#endif

static ssize_t preadv(int fd, const struct iovec *iov, int iovcnt, off_t offset)
{
    uint32_t pos_high = (offset >> 32) & 0xffffffff;
    uint32_t pos_low  =  offset        & 0xffffffff;

    return syscall(__NR_preadv, fd, iov, iovcnt, pos_high, pos_low);
}

static ssize_t pwritev(int fd, const struct iovec *iov, int iovcnt, off_t offset)
{
    uint32_t pos_high = (offset >> 32) & 0xffffffff;
    uint32_t pos_low  =  offset        & 0xffffffff;

    return syscall(__NR_pwritev, fd, iov, iovcnt, pos_high, pos_low);
}

/* ----------------------------------------------------------------- */
/* demo/test app                                                     */

static char filename[] = "/tmp/preadv-XXXXXX";
static char outbuf[11] = "0123456789";
static char inbuf[11]  = "----------";

static struct iovec ovec[2] = {{
        .iov_base = outbuf + 5,
        .iov_len  = 5,
    },{
        .iov_base = outbuf + 0,
        .iov_len  = 5,
    }};

static struct iovec ivec[3] = {{
        .iov_base = inbuf + 6,
        .iov_len  = 2,
    },{
        .iov_base = inbuf + 4,
        .iov_len  = 2,
    },{
        .iov_base = inbuf + 2,
        .iov_len  = 2,
    }};

void cleanup(void)
{
    unlink(filename);
}

int main(int argc, char **argv)
{
    int fd, rc;

    fd = mkstemp(filename);
    if (-1 == fd) {
        perror("mkstemp");
        exit(1);
    }
    atexit(cleanup);

    /* write to file: "56789-01234" */
    rc = pwritev(fd, ovec, 2, 0);
    if (rc < 0) {
        perror("pwritev");
        exit(1);
    }

    /* read from file: "78-90-12" */
    rc = preadv(fd, ivec, 3, 2);
    if (rc < 0) {
        perror("preadv");
        exit(1);
    }

    printf("result  : %s\n", inbuf);
    printf("expected: %s\n", "--129078--");
    exit(0);
}

This patch:

Factor out some code from compat_sys_readv() which can be shared with the
upcoming compat_sys_preadv().
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: <linux-api@vger.kernel.org>
Cc: <linux-arch@vger.kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Decompression errors can arise due to corruption of compressed blocks on
flash or in memory.  This patch propagates errors detected during
decompression back to the block layer.
Signed-off-by: NDavid VomLehn <dvomlehn@cisco.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NMike Frysinger <vapier.adi@gmail.com>
Signed-off-by: NBryan Wu <cooloney@kernel.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Greg Ungerer <gerg@snapgear.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

hppfs_read_file() may return (ssize_t) -ENOMEM, or -EFAULT.  When stored
in size_t 'count', these errors will not be noticed, a large value will be
added to *ppos.
Signed-off-by: NRoel Kluin <roel.kluin@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Sometimes block_write_begin() can map buffers in a page but later we
fail to copy data into those buffers (because the source page has been
paged out in the mean time).  We then end up with !uptodate mapped
buffers.  To add a bit more to the confusion, block_write_end() does
not commit any data (and thus does not any mark buffers as uptodate) if
we didn't succeed with copying all the data.

Commit f4fc66a8 (ext3: convert to new
aops) missed these cases and thus we were inserting non-uptodate
buffers to transaction's list which confuses JBD code and it reports IO
errors, aborts a transaction and generally makes users afraid about
their data ;-P.

This patch fixes the problem by reorganizing ext3_..._write_end() code
to first call block_write_end() to mark buffers with valid data
uptodate and after that we file only uptodate buffers to transaction's
lists.

We also fix a problem where we could leave blocks allocated beyond i_size
(i_disksize in fact) because of failed write. We now add inode to orphan
list when write fails (to be safe in case we crash) and then truncate blocks
beyond i_size in a separate transaction.
Signed-off-by: NJan Kara <jack@suse.cz>
Reviewed-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: <linux-ext4@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

ext3_iget() returns -ESTALE if invoked on a deleted inode, in order to
report errors to NFS properly.  However, in ext[234]_lookup(), this
-ESTALE can be propagated to userspace if the filesystem is corrupted such
that a directory entry references a deleted inode.  This leads to a
misleading error message - "Stale NFS file handle" - and confusion on the
part of the admin.

The bug can be easily reproduced by creating a new filesystem, making a
link to an unused inode using debugfs, then mounting and attempting to ls
-l said link.

This patch thus changes ext3_lookup to return -EIO if it receives -ESTALE
from ext3_iget(), as ext3 does for other filesystem metadata corruption;
and also invokes the appropriate ext*_error functions when this case is
detected.
Signed-off-by: NBryan Donlan <bdonlan@gmail.com>
Cc: <linux-ext4@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Use unsigned instead of int for the parameter which carries a blocksize.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: NWei Yongjun <yjwei@cn.fujitsu.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

On 32-bit system with CONFIG_LBD getblk can fail because provided block
number is too big. Make JBD gracefully handle that.
Signed-off-by: NJan Kara <jack@suse.cz>
Cc: <dmaciejak@fortinet.com>
Cc: <linux-ext4@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Reformat ext3/ioctl.c to make it look more like ext4/ioctl.c and remove
the BKL around ext3_ioctl().
Signed-off-by: NCyrus Massoumi <cyrusm@gmx.net>
Cc: <linux-ext4@vger.kernel.org>
Acked-by: NJan Kara <jack@ucw.cz>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Check bh->b_blocknr only if BH_Mapped is set.

akpm: I doubt if b_blocknr is ever uninitialised here, but it could
conceivably cause a problem if we're doing a lookup for block zero.
Signed-off-by: NNikanth Karthikesan <knikanth@suse.de>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The dirtied_when value on an inode is supposed to represent the first time
that an inode has one of its pages dirtied.  This value is in units of
jiffies.  It's used in several places in the writeback code to determine
when to write out an inode.

The problem is that these checks assume that dirtied_when is updated
periodically.  If an inode is continuously being used for I/O it can be
persistently marked as dirty and will continue to age.  Once the time
compared to is greater than or equal to half the maximum of the jiffies
type, the logic of the time_*() macros inverts and the opposite of what is
needed is returned.  On 32-bit architectures that's just under 25 days
(assuming HZ == 1000).

As the least-recently dirtied inode, it'll end up being the first one that
pdflush will try to write out.  sync_sb_inodes does this check:

	/* Was this inode dirtied after sync_sb_inodes was called? */
 	if (time_after(inode->dirtied_when, start))
 		break;

...but now dirtied_when appears to be in the future.  sync_sb_inodes bails
out without attempting to write any dirty inodes.  When this occurs,
pdflush will stop writing out inodes for this superblock.  Nothing can
unwedge it until jiffies moves out of the problematic window.

This patch fixes this problem by changing the checks against dirtied_when
to also check whether it appears to be in the future.  If it does, then we
consider the value to be far in the past.

This should shrink the problematic window of time to such a small period
(30s) as not to matter.
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NWu Fengguang <fengguang.wu@intel.com>
Acked-by: NIan Kent <raven@themaw.net>
Cc: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

clear_inode() will switch inode state from I_FREEING to I_CLEAR, and do so
_outside_ of inode_lock.  So any I_FREEING testing is incomplete without a
coupled testing of I_CLEAR.

So add I_CLEAR tests to drop_pagecache_sb(), generic_sync_sb_inodes() and
add_dquot_ref().

Masayoshi MIZUMA discovered the bug in drop_pagecache_sb() and Jan Kara
reminds fixing the other two cases.

Masayoshi MIZUMA has a nice panic flow:

=====================================================================
            [process A]               |        [process B]
 |                                    |
 |    prune_icache()                  | drop_pagecache()
 |      spin_lock(&inode_lock)        |   drop_pagecache_sb()
 |      inode->i_state |= I_FREEING;  |       |
 |      spin_unlock(&inode_lock)      |       V
 |          |                         |     spin_lock(&inode_lock)
 |          V                         |         |
 |      dispose_list()                |         |
 |        list_del()                  |         |
 |        clear_inode()               |         |
 |          inode->i_state = I_CLEAR  |         |
 |            |                       |         V
 |            |                       |      if (inode->i_state & (I_FREEING|I_WILL_FREE))
 |            |                       |              continue;           <==== NOT MATCH
 |            |                       |
 |            |                       | (DANGER from here on! Accessing disposing inode!)
 |            |                       |
 |            |                       |      __iget()
 |            |                       |        list_move() <===== PANIC on poisoned list !!
 V            V                       |
(time)
=====================================================================
Reported-by: NMasayoshi MIZUMA <m.mizuma@jp.fujitsu.com>
Reviewed-by: NJan Kara <jack@suse.cz>
Signed-off-by: NWu Fengguang <fengguang.wu@intel.com>
Cc: <stable@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fix a number of issues with the per-MM VMA patch:

 (1) Make mmap_pages_allocated an atomic_long_t, just in case this is used on
     a NOMMU system with more than 2G pages.  Makes no difference on a 32-bit
     system.

 (2) Report vma->vm_pgoff * PAGE_SIZE as a 64-bit value, not a 32-bit value,
     lest it overflow.

 (3) Move the allocation of the vm_area_struct slab back for fork.c.

 (4) Use KMEM_CACHE() for both vm_area_struct and vm_region slabs.

 (5) Use BUG_ON() rather than if () BUG().

 (6) Make the default validate_nommu_regions() a static inline rather than a
     #define.

 (7) Make free_page_series()'s objection to pages with a refcount != 1 more
     informative.

 (8) Adjust the __put_nommu_region() banner comment to indicate that the
     semaphore must be held for writing.

 (9) Limit the number of warnings about munmaps of non-mmapped regions.
Reported-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Cc: Greg Ungerer <gerg@snapgear.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This fixes unaligned accesses in nsm_init_private() when
creating nlm_reboot keys.
Signed-off-by: NMans Rullgard <mans@mansr.com>
Reviewed-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

A deadlock can occur when user space uses a signal (autofs version 4 uses
SIGCHLD for this) to effect expire completion.

The order of events is:

Expire process completes, but before being able to send SIGCHLD to it's parent
...

Another process walks onto a different mount point and drops the directory
inode semaphore prior to sending the request to the daemon as it must ...

A third process does an lstat on on the expired mount point causing it to wait
on expire completion (unfortunately) holding the directory semaphore.

The mount request then arrives at the daemon which does an lstat and,
deadlock.

For some time I was concerned about releasing the directory semaphore around
the expire wait in autofs4_lookup as well as for the mount call back.  I
finally realized that the last round of changes in this function made the
expiring dentry and the lookup dentry separate and distinct so the check and
possible wait can be done anywhere prior to the mount call back.  This patch
moves the check to just before the mount call back and inside the directory
inode mutex release.
Signed-off-by: NIan Kent <raven@themaw.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

A significant portion of the autofs_dev_ioctl_expire() and
autofs4_expire_multi() functions is duplicated code.  This patch cleans that
up.
Signed-off-by: NIan Kent <raven@themaw.net>
Signed-off-by: NJeff Moyer <jmoyer@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Use kzfree() instead of memset() + kfree().
Signed-off-by: NJohannes Weiner <hannes@cmpxchg.org>
Reviewed-by: NPekka Enberg <penberg@cs.helsinki.fi>
Acked-by: NTyler Hicks <tyhicks@linux.vnet.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Addresses http://bugzilla.kernel.org/show_bug.cgi?id=12843

"I use ramfs instead of tmpfs for /tmp because I don't use swap on my
laptop.  Some apps need 1777 mode for /tmp directory, but ramfs does not
support 'mode=' mount option."
Reported-by: NAvan Anishchuk <matimatik@gmail.com>
Signed-off-by: NWu Fengguang <fengguang.wu@intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Introduce keyed event wakeups inside the eventfd code.
Signed-off-by: NDavide Libenzi <davidel@xmailserver.org>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: David Miller <davem@davemloft.net>
Cc: William Lee Irwin III <wli@movementarian.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Use the events hint now sent by some devices, to avoid unnecessary wakeups
for events that are of no interest for the caller.  This code handles both
devices that are sending keyed events, and the ones that are not (and
event the ones that sometimes send events, and sometimes don't).

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: NDavide Libenzi <davidel@xmailserver.org>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: David Miller <davem@davemloft.net>
Cc: William Lee Irwin III <wli@movementarian.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>