src/patches/suse-2.6.27.39/patches.suse/quota-Implement-function-for-scanning-active-dquots.patch

   1 From: Jan Kara <jack@suse.cz>
   2 References: fate#302681
   3 Subject: [PATCH 17/28] quota: Implement function for scanning active dquots
   4 Patch-mainline: 2.6.29?
   5
   6 OCFS2 needs to scan all active dquots once in a while and sync quota
   7 information among cluster nodes. Provide a helper function for it so
   8 that it does not have to reimplement internally a list which VFS
   9 already has. Moreover this function is probably going to be useful
  10 for other clustered filesystems if they decide to use VFS quotas.
  11
  12 Signed-off-by: Jan Kara <jack@suse.cz>
  13 ---
  14  fs/dquot.c               |   36 ++++++++++++++++++++++++++++++++++++
  15  include/linux/quotaops.h |    3 +++
  16  2 files changed, 39 insertions(+), 0 deletions(-)
  17
  18 diff --git a/fs/dquot.c b/fs/dquot.c
  19 index 9fb1d71..6a17416 100644
  20 --- a/fs/dquot.c
  21 +++ b/fs/dquot.c
  22 @@ -476,6 +476,41 @@ restart:
  23         spin_unlock(&dq_list_lock);
  24  }
  25
  26 +/* Call callback for every active dquot on given filesystem */
  27 +int dquot_scan_active(struct super_block *sb,
  28 +                     int (*fn)(struct dquot *dquot, unsigned long priv),
  29 +                     unsigned long priv)
  30 +{
  31 +       struct dquot *dquot, *old_dquot = NULL;
  32 +       int ret = 0;
  33 +
  34 +       mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
  35 +       spin_lock(&dq_list_lock);
  36 +       list_for_each_entry(dquot, &inuse_list, dq_inuse) {
  37 +               if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags))
  38 +                       continue;
  39 +               if (dquot->dq_sb != sb)
  40 +                       continue;
  41 +               /* Now we have active dquot so we can just increase use count */
  42 +               atomic_inc(&dquot->dq_count);
  43 +               dqstats.lookups++;
  44 +               spin_unlock(&dq_list_lock);
  45 +               dqput(old_dquot);
  46 +               old_dquot = dquot;
  47 +               ret = fn(dquot, priv);
  48 +               if (ret < 0)
  49 +                       goto out;
  50 +               spin_lock(&dq_list_lock);
  51 +               /* We are safe to continue now because our dquot could not
  52 +                * be moved out of the inuse list while we hold the reference */
  53 +       }
  54 +       spin_unlock(&dq_list_lock);
  55 +out:
  56 +       dqput(old_dquot);
  57 +       mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
  58 +       return ret;
  59 +}
  60 +
  61  int vfs_quota_sync(struct super_block *sb, int type)
  62  {
  63         struct list_head *dirty;
  64 @@ -2316,6 +2351,7 @@ EXPORT_SYMBOL(vfs_quota_on_path);
  65  EXPORT_SYMBOL(vfs_quota_on_mount);
  66  EXPORT_SYMBOL(vfs_quota_disable);
  67  EXPORT_SYMBOL(vfs_quota_off);
  68 +EXPORT_SYMBOL(dquot_scan_active);
  69  EXPORT_SYMBOL(vfs_quota_sync);
  70  EXPORT_SYMBOL(vfs_get_dqinfo);
  71  EXPORT_SYMBOL(vfs_set_dqinfo);
  72 diff --git a/include/linux/quotaops.h b/include/linux/quotaops.h
  73 index 1f990f2..f2147eb 100644
  74 --- a/include/linux/quotaops.h
  75 +++ b/include/linux/quotaops.h
  76 @@ -31,6 +31,9 @@ int dquot_drop_locked(struct inode *inode);
  77  struct dquot *dqget(struct super_block *sb, unsigned int id, int type);
  78  void dqput(struct dquot *dquot);
  79  int dquot_is_cached(struct super_block *sb, unsigned int id, int type);
  80 +int dquot_scan_active(struct super_block *sb,
  81 +                     int (*fn)(struct dquot *dquot, unsigned long priv),
  82 +                     unsigned long priv);
  83
  84  int dquot_alloc_space(struct inode *inode, qsize_t number, int prealloc);
  85  int dquot_alloc_inode(const struct inode *inode, qsize_t number);
  86 --
  87 1.5.2.4
  88