src/patches/suse-2.6.27.25/patches.fixes/remount-no-shrink-dcache

   1 From: Olaf Kirch <okir@suse.de>
   2 Subject: Do not call shrink_dcache_sb when remounting procfs etc
   3 References: 165672
   4
   5 Avoid calls to shrink_dcache_sb when mounting a file system that
   6 uses get_sb_single. shrink_dcache_sb is costly. On large ia64
   7 systems, this will keep the dcache lock for > 60 seconds at
   8 a stretch.
   9
  10 Signed-off-by: Olaf Kirch <okir@suse.de>
  11
  12  fs/super.c |   36 +++++++++++++++++++++++-------------
  13  1 file changed, 23 insertions(+), 13 deletions(-)
  14
  15 --- a/fs/super.c
  16 +++ b/fs/super.c
  17 @@ -597,16 +597,10 @@ retry:
  18         file_list_unlock();
  19  }
  20
  21 -/**
  22 - *     do_remount_sb - asks filesystem to change mount options.
  23 - *     @sb:    superblock in question
  24 - *     @flags: numeric part of options
  25 - *     @data:  the rest of options
  26 - *      @force: whether or not to force the change
  27 - *
  28 - *     Alters the mount options of a mounted file system.
  29 - */
  30 -int do_remount_sb(struct super_block *sb, int flags, void *data, int force)
  31 +#define REMOUNT_FORCE          1
  32 +#define REMOUNT_SHRINK_DCACHE  2
  33 +
  34 +static int __do_remount_sb(struct super_block *sb, int flags, void *data, int rflags)
  35  {
  36         int retval;
  37         int remount_rw;
  38 @@ -617,13 +611,14 @@ int do_remount_sb(struct super_block *sb
  39  #endif
  40         if (flags & MS_RDONLY)
  41                 acct_auto_close(sb);
  42 -       shrink_dcache_sb(sb);
  43 +       if (rflags & REMOUNT_SHRINK_DCACHE)
  44 +               shrink_dcache_sb(sb);
  45         fsync_super(sb);
  46
  47         /* If we are remounting RDONLY and current sb is read/write,
  48            make sure there are no rw files opened */
  49         if ((flags & MS_RDONLY) && !(sb->s_flags & MS_RDONLY)) {
  50 -               if (force)
  51 +               if (rflags & REMOUNT_FORCE)
  52                         mark_files_ro(sb);
  53                 else if (!fs_may_remount_ro(sb))
  54                         return -EBUSY;
  55 @@ -646,6 +641,21 @@ int do_remount_sb(struct super_block *sb
  56         return 0;
  57  }
  58
  59 +/**
  60 + *     do_remount_sb - asks filesystem to change mount options.
  61 + *     @sb:    superblock in question
  62 + *     @flags: numeric part of options
  63 + *     @data:  the rest of options
  64 + *      @force: whether or not to force the change
  65 + *
  66 + *     Alters the mount options of a mounted file system.
  67 + */
  68 +int do_remount_sb(struct super_block *sb, int flags, void *data, int force)
  69 +{
  70 +       return __do_remount_sb(sb, flags, data,
  71 +                       REMOUNT_SHRINK_DCACHE|(force? REMOUNT_FORCE : 0));
  72 +}
  73 +
  74  static void do_emergency_remount(unsigned long foo)
  75  {
  76         struct super_block *sb;
  77 @@ -877,7 +887,7 @@ int get_sb_single(struct file_system_typ
  78                 }
  79                 s->s_flags |= MS_ACTIVE;
  80         }
  81 -       do_remount_sb(s, flags, data, 0);
  82 +       __do_remount_sb(s, flags, data, 0);
  83         return simple_set_mnt(mnt, s);
  84  }
  85