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LU-12561 kernel: Remove 2.6 based SLES11 support
[fs/lustre-release.git] / lustre / kernel_patches / patches / quota-avoid-dqget-calls.patch
index 0a0c6cc..bf5107c 100644 (file)
@@ -1,62 +1,62 @@
-In dquot_initialize(), we'd call dqget() only when i_dquot not
-initialized, which can avoid 2 pair of dqget()/dqput() in most
-case. It could relieve the global locks contenion caused by
-dqget()/dqput().
-Index: linux-2.6.32-358.0.1.el6/fs/quota/dquot.c
+commit 1ea06bec78a128adc995ca32bd906a6c9bb9cf91
+Author: Niu Yawei <yawei.niu@gmail.com>
+Date:   Wed Jun 4 12:20:30 2014 +0800
+
+    quota: avoid unnecessary dqget()/dqput() calls
+
+    Avoid unnecessary dqget()/dqput() calls in __dquot_initialize(),
+    that will introduce global lock contention otherwise.
+
+    Signed-off-by: Lai Siyao <lai.siyao@intel.com>
+    Signed-off-by: Niu Yawei <yawei.niu@intel.com>
+    Signed-off-by: Jan Kara <jack@suse.cz>
+Index: linux-2.6.32-431.5.1.el6/fs/quota/dquot.c
 ===================================================================
---- linux-2.6.32-358.0.1.el6.orig/fs/quota/dquot.c
-+++ linux-2.6.32-358.0.1.el6/fs/quota/dquot.c
+--- linux-2.6.32-431.5.1.el6.orig/fs/quota/dquot.c
++++ linux-2.6.32-431.5.1.el6/fs/quota/dquot.c
 @@ -1230,7 +1230,7 @@ static int info_bdq_free(struct dquot *d
  int dquot_initialize(struct inode *inode, int type)
  {
        unsigned int id = 0;
 -      int cnt, ret = 0;
-+      int cnt, ret = 0, dq_get = 0;
++      int cnt, ret = 0, init_needed = 0;
        struct dquot *got[MAXQUOTAS] = { NULL, NULL };
        struct super_block *sb = inode->i_sb;
        qsize_t rsv;
-@@ -1240,7 +1240,14 @@ int dquot_initialize(struct inode *inode
-       if (IS_NOQUOTA(inode))
-               return 0;
--      /* First get references to structures we might need. */
-+      /* In most case, the i_dquot should have been initialized, except
-+       * the newly allocated one. We'd always try to skip the dqget() and
-+       * dqput() calls to avoid unnecessary global lock contention. */
-+      if (!(inode->i_state & I_NEW))
-+              goto init_idquot;
-+
-+get_dquots:
-+      dq_get = 1;
+@@ -1244,6 +1244,15 @@ int dquot_initialize(struct inode *inode
        for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
                if (type != -1 && cnt != type)
                        continue;
-@@ -1254,7 +1261,7 @@ int dquot_initialize(struct inode *inode
-               }
++              /*
++               * The i_dquot should have been initialized in most cases,
++               * we check it without locking here to avoid unnecessary
++               * dqget()/dqput() calls.
++               */
++              if (inode->i_dquot[cnt])
++                      continue;
++              init_needed = 1;
++
+               switch (cnt) {
+               case USRQUOTA:
+                       id = inode->i_uid;
+@@ -1255,6 +1264,10 @@ int dquot_initialize(struct inode *inode
                got[cnt] = dqget(sb, id, cnt);
        }
--
-+init_idquot:
++      /* All required i_dquot has been initialized */
++      if (!init_needed)
++              return 0;
++
        spin_lock(&inode->i_lock);
        if (IS_NOQUOTA(inode))
                goto out_err;
-@@ -1265,6 +1272,10 @@ int dquot_initialize(struct inode *inode
+@@ -1264,6 +1277,9 @@ int dquot_initialize(struct inode *inode
+               /* Avoid races with quotaoff() */
                if (!sb_has_quota_active(sb, cnt))
                        continue;
++              /* We could race with quotaon or dqget() could have failed */
++              if (!got[cnt])
++                      continue;
                if (!inode->i_dquot[cnt]) {
-+                      if (dq_get == 0) {
-+                              spin_unlock(&inode->i_lock);
-+                              goto get_dquots;
-+                      }
                        inode->i_dquot[cnt] = got[cnt];
                        got[cnt] = NULL;
-                       /*
-@@ -1272,7 +1283,7 @@ int dquot_initialize(struct inode *inode
-                        * did a write before quota was turned on
-                        */
-                       rsv = inode_get_rsv_space(inode);
--                      if (unlikely(rsv)) {
-+                      if (unlikely(rsv) && likely(inode->i_dquot[cnt])) {
-                               spin_lock(&dq_data_lock);
-                               dquot_resv_space(inode->i_dquot[cnt], rsv);
-                               spin_unlock(&dq_data_lock);