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  1. 09 7月, 2008 1 次提交
  3. 05 7月, 2008 1 次提交
  5. 30 4月, 2008 1 次提交
  7. 29 4月, 2008 1 次提交
  9. 28 4月, 2008 8 次提交
  11. 19 4月, 2008 3 次提交
  13. 31 3月, 2008 1 次提交
  15. 19 3月, 2008 1 次提交
  17. 05 3月, 2008 1 次提交
  19. 15 2月, 2008 2 次提交
  21. 09 2月, 2008 2 次提交
  23. 08 2月, 2008 1 次提交
  25. 07 2月, 2008 2 次提交
  27. 06 2月, 2008 1 次提交
    • C
      Pagecache zeroing: zero_user_segment, zero_user_segments and zero_user · eebd2aa3
      由 Christoph Lameter 提交于 
      Simplify page cache zeroing of segments of pages through 3 functions

zero_user_segments(page, start1, end1, start2, end2)

        Zeros two segments of the page. It takes the position where to
        start and end the zeroing which avoids length calculations and
	makes code clearer.

zero_user_segment(page, start, end)

        Same for a single segment.

zero_user(page, start, length)

        Length variant for the case where we know the length.

We remove the zero_user_page macro. Issues:

1. Its a macro. Inline functions are preferable.

2. The KM_USER0 macro is only defined for HIGHMEM.

   Having to treat this special case everywhere makes the
   code needlessly complex. The parameter for zeroing is always
   KM_USER0 except in one single case that we open code.

Avoiding KM_USER0 makes a lot of code not having to be dealing
with the special casing for HIGHMEM anymore. Dealing with
kmap is only necessary for HIGHMEM configurations. In those
configurations we use KM_USER0 like we do for a series of other
functions defined in highmem.h.

Since KM_USER0 is depends on HIGHMEM the existing zero_user_page
function could not be a macro. zero_user_* functions introduced
here can be be inline because that constant is not used when these
functions are called.

Also extract the flushing of the caches to be outside of the kmap.

[akpm@linux-foundation.org: fix nfs and ntfs build]
[akpm@linux-foundation.org: fix ntfs build some more]
Signed-off-by: NChristoph Lameter <clameter@sgi.com>
Cc: Steven French <sfrench@us.ibm.com>
Cc: Michael Halcrow <mhalcrow@us.ibm.com>
Cc: <linux-ext4@vger.kernel.org>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Anton Altaparmakov <aia21@cantab.net>
Cc: Mark Fasheh <mark.fasheh@oracle.com>
Cc: David Chinner <dgc@sgi.com>
Cc: Michael Halcrow <mhalcrow@us.ibm.com>
Cc: Steven French <sfrench@us.ibm.com>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      eebd2aa3
  29. 03 2月, 2008 1 次提交
  31. 06 12月, 2007 1 次提交
    • A
      proc: fix proc_dir_entry refcounting · 5a622f2d
      由 Alexey Dobriyan 提交于 
      Creating PDEs with refcount 0 and "deleted" flag has problems (see below).
Switch to usual scheme:
* PDE is created with refcount 1
* every de_get does +1
* every de_put() and remove_proc_entry() do -1
* once refcount reaches 0, PDE is freed.

This elegantly fixes at least two following races (both observed) without
introducing new locks, without abusing old locks, without spreading
lock_kernel():

1) PDE leak

remove_proc_entry			de_put
-----------------			------
			[refcnt = 1]
if (atomic_read(&de->count) == 0)
					if (atomic_dec_and_test(&de->count))
						if (de->deleted)
							/* also not taken! */
							free_proc_entry(de);
else
	de->deleted = 1;
		[refcount=0, deleted=1]

2) use after free

remove_proc_entry			de_put
-----------------			------
			[refcnt = 1]

					if (atomic_dec_and_test(&de->count))
if (atomic_read(&de->count) == 0)
	free_proc_entry(de);
						/* boom! */
						if (de->deleted)
							free_proc_entry(de);

BUG: unable to handle kernel paging request at virtual address 6b6b6b6b
printing eip: c10acdda *pdpt = 00000000338f8001 *pde = 0000000000000000
Oops: 0000 [#1] PREEMPT SMP
Modules linked in: af_packet ipv6 cpufreq_ondemand loop serio_raw psmouse k8temp hwmon sr_mod cdrom
Pid: 23161, comm: cat Not tainted (2.6.24-rc2-8c086340 #4)
EIP: 0060:[<c10acdda>] EFLAGS: 00210097 CPU: 1
EIP is at strnlen+0x6/0x18
EAX: 6b6b6b6b EBX: 6b6b6b6b ECX: 6b6b6b6b EDX: fffffffe
ESI: c128fa3b EDI: f380bf34 EBP: ffffffff ESP: f380be44
 DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068
Process cat (pid: 23161, ti=f380b000 task=f38f2570 task.ti=f380b000)
Stack: c10ac4f0 00000278 c12ce000 f43cd2a8 00000163 00000000 7da86067 00000400
       c128fa20 00896b18 f38325a8 c128fe20 ffffffff 00000000 c11f291e 00000400
       f75be300 c128fa20 f769c9a0 c10ac779 f380bf34 f7bfee70 c1018e6b f380bf34
Call Trace:
 [<c10ac4f0>] vsnprintf+0x2ad/0x49b
 [<c10ac779>] vscnprintf+0x14/0x1f
 [<c1018e6b>] vprintk+0xc5/0x2f9
 [<c10379f1>] handle_fasteoi_irq+0x0/0xab
 [<c1004f44>] do_IRQ+0x9f/0xb7
 [<c117db3b>] preempt_schedule_irq+0x3f/0x5b
 [<c100264e>] need_resched+0x1f/0x21
 [<c10190ba>] printk+0x1b/0x1f
 [<c107c8ad>] de_put+0x3d/0x50
 [<c107c8f8>] proc_delete_inode+0x38/0x41
 [<c107c8c0>] proc_delete_inode+0x0/0x41
 [<c1066298>] generic_delete_inode+0x5e/0xc6
 [<c1065aa9>] iput+0x60/0x62
 [<c1063c8e>] d_kill+0x2d/0x46
 [<c1063fa9>] dput+0xdc/0xe4
 [<c10571a1>] __fput+0xb0/0xcd
 [<c1054e49>] filp_close+0x48/0x4f
 [<c1055ee9>] sys_close+0x67/0xa5
 [<c10026b6>] sysenter_past_esp+0x5f/0x85
=======================
Code: c9 74 0c f2 ae 74 05 bf 01 00 00 00 4f 89 fa 5f 89 d0 c3 85 c9 57 89 c7 89 d0 74 05 f2 ae 75 01 4f 89 f8 5f c3 89 c1 89 c8 eb 06 <80> 38 00 74 07 40 4a 83 fa ff 75 f4 29 c8 c3 90 90 90 57 83 c9
EIP: [<c10acdda>] strnlen+0x6/0x18 SS:ESP 0068:f380be44

Also, remove broken usage of ->deleted from reiserfs: if sget() succeeds,
module is already pinned and remove_proc_entry() can't happen => nobody
can mark PDE deleted.

Dummy proc root in netns code is not marked with refcount 1. AFAICS, we
never get it, it's just for proper /proc/net removal. I double checked
CLONE_NETNS continues to work.

Patch survives many hours of modprobe/rmmod/cat loops without new bugs
which can be attributed to refcounting.
Signed-off-by: NAlexey Dobriyan <adobriyan@sw.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      5a622f2d
  33. 15 11月, 2007 2 次提交
    • F
      reiserfs: don't drop PG_dirty when releasing sub-page-sized dirty file · c06a018f
      由 Fengguang Wu 提交于 
      This is not a new problem in 2.6.23-git17.  2.6.22/2.6.23 is buggy in the
same way.

Reiserfs could accumulate dirty sub-page-size files until umount time.
They cannot be synced to disk by pdflush routines or explicit `sync'
commands.  Only `umount' can do the trick.

The direct cause is: the dirty page's PG_dirty is wrongly _cleared_.
Call trace:
	 [<ffffffff8027e920>] cancel_dirty_page+0xd0/0xf0
	 [<ffffffff8816d470>] :reiserfs:reiserfs_cut_from_item+0x660/0x710
	 [<ffffffff8816d791>] :reiserfs:reiserfs_do_truncate+0x271/0x530
	 [<ffffffff8815872d>] :reiserfs:reiserfs_truncate_file+0xfd/0x3b0
	 [<ffffffff8815d3d0>] :reiserfs:reiserfs_file_release+0x1e0/0x340
	 [<ffffffff802a187c>] __fput+0xcc/0x1b0
	 [<ffffffff802a1ba6>] fput+0x16/0x20
	 [<ffffffff8029e676>] filp_close+0x56/0x90
	 [<ffffffff8029fe0d>] sys_close+0xad/0x110
	 [<ffffffff8020c41e>] system_call+0x7e/0x83

Fix the bug by removing the cancel_dirty_page() call. Tests show that
it causes no bad behaviors on various write sizes.

=== for the patient ===
Here are more detailed demonstrations of the problem.

1) the page has both PG_dirty(D)/PAGECACHE_TAG_DIRTY(d) after being written to;
   and then only PAGECACHE_TAG_DIRTY(d) remains after the file is closed.

------------------------------ screen 0 ------------------------------
[T0] root /home/wfg# cat > /test/tiny
[T1] hi
[T2] root /home/wfg#

------------------------------ screen 1 ------------------------------
[T1] root /home/wfg# echo /test/tiny > /proc/filecache
[T1] root /home/wfg# cat /proc/filecache
     # file /test/tiny
     # flags R:referenced A:active M:mmap U:uptodate D:dirty W:writeback O:owner B:buffer d:dirty w:writeback
     # idx   len     state   refcnt
     0       1       ___UD__Bd_      2
[T2] root /home/wfg# cat /proc/filecache
     # file /test/tiny
     # flags R:referenced A:active M:mmap U:uptodate D:dirty W:writeback O:owner B:buffer d:dirty w:writeback
     # idx   len     state   refcnt
     0       1       ___U___Bd_      2

2) note the non-zero 'cancelled_write_bytes' after /tmp/hi is copied.

------------------------------ screen 0 ------------------------------
[T0] root /home/wfg# echo hi > /tmp/hi
[T1] root /home/wfg# cp /tmp/hi /dev/stdin /test
[T2] hi
[T3] root /home/wfg#

------------------------------ screen 1 ------------------------------
[T1] root /proc/4397# cd /proc/`pidof cp`
[T1] root /proc/4713# cat io
     rchar: 8396
     wchar: 3
     syscr: 20
     syscw: 1
     read_bytes: 0
     write_bytes: 20480
     cancelled_write_bytes: 4096
[T2] root /proc/4713# cat io
     rchar: 8399
     wchar: 6
     syscr: 21
     syscw: 2
     read_bytes: 0
     write_bytes: 24576
     cancelled_write_bytes: 4096

//Question: the 'write_bytes' is a bit more than expected ;-)
Tested-by: NMaxim Levitsky <maximlevitsky@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: NFengguang Wu <wfg@mail.ustc.edu.cn>
Reviewed-by: NChris Mason <chris.mason@oracle.com>
Cc: <stable@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      c06a018f
    • J
      Forbid user to change file flags on quota files · e47776a0
      由 Jan Kara 提交于 
      Forbid user from changing file flags on quota files.  User has no bussiness
in playing with these flags when quota is on.  Furthermore there is a
remote possibility of deadlock due to a lock inversion between quota file's
i_mutex and transaction's start (i_mutex for quota file is locked only when
trasaction is started in quota operations) in ext3 and ext4.
Signed-off-by: NJan Kara <jack@suse.cz>
Cc: LIOU Payphone <lioupayphone@gmail.com>
Cc: <linux-ext4@vger.kernel.org>
Acked-by: NDave Kleikamp <shaggy@austin.ibm.com>
Cc: <reiserfs-dev@namesys.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      e47776a0
  35. 22 10月, 2007 2 次提交
  37. 20 10月, 2007 8 次提交