Gitweb:     
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=c06a018fa5362fa9ed0768bd747c0fab26bc8849
Commit:     c06a018fa5362fa9ed0768bd747c0fab26bc8849
Parent:     7bb67c14fd3778504fb77da30ce11582336dfced
Author:     Fengguang Wu <[EMAIL PROTECTED]>
AuthorDate: Wed Nov 14 16:59:54 2007 -0800
Committer:  Linus Torvalds <[EMAIL PROTECTED]>
CommitDate: Wed Nov 14 18:45:41 2007 -0800

    reiserfs: don't drop PG_dirty when releasing sub-page-sized dirty file
    
    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: Maxim Levitsky <[EMAIL PROTECTED]>
    Cc: Peter Zijlstra <[EMAIL PROTECTED]>
    Cc: Jeff Mahoney <[EMAIL PROTECTED]>
    Signed-off-by: Fengguang Wu <[EMAIL PROTECTED]>
    Reviewed-by: Chris Mason <[EMAIL PROTECTED]>
    Cc: <[EMAIL PROTECTED]>
    Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
    Signed-off-by: Linus Torvalds <[EMAIL PROTECTED]>
---
 fs/reiserfs/stree.c |    3 ---
 1 files changed, 0 insertions(+), 3 deletions(-)

diff --git a/fs/reiserfs/stree.c b/fs/reiserfs/stree.c
index ca41567..d2db241 100644
--- a/fs/reiserfs/stree.c
+++ b/fs/reiserfs/stree.c
@@ -1458,9 +1458,6 @@ static void unmap_buffers(struct page *page, loff_t pos)
                                }
                                bh = next;
                        } while (bh != head);
-                       if (PAGE_SIZE == bh->b_size) {
-                               cancel_dirty_page(page, PAGE_CACHE_SIZE);
-                       }
                }
        }
 }
-
To unsubscribe from this list: send the line "unsubscribe git-commits-head" in
the body of a message to [EMAIL PROTECTED]
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Reply via email to