gfs2: allow quota_check and inplace_reserve to return available blocks

struct gfs2_alloc_parms is passed to gfs2_quota_check() and
gfs2_inplace_reserve() with ap->target containing the number of
blocks being requested for allocation in the current operation.

We add a new field to struct gfs2_alloc_parms called 'allowed'.
gfs2_quota_check() and gfs2_inplace_reserve() return the max
blocks allowed by quota and the max blocks allowed by the chosen
rgrp respectively in 'allowed'.

A new field 'min_target', when non-zero, tells gfs2_quota_check()
and gfs2_inplace_reserve() to not return -EDQUOT/-ENOSPC when
there are atleast 'min_target' blocks allowable/available. The
assumption is that the caller is ok with just 'min_target' blocks
and will likely proceed with allocating them.

Signed-off-by: Abhi Das <adas@redhat.com>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Acked-by: Steven Whitehouse <swhiteho@redhat.com>

diff --git a/fs/gfs2/incore.h b/fs/gfs2/incore.h
index 3a4ea50..58b75ab 100644 (file)
--- a/fs/gfs2/incore.h
+++ b/fs/gfs2/incore.h
@@ -302,7 +302,9 @@ struct gfs2_blkreserv {
  */
 struct gfs2_alloc_parms {
        u64 target;
+       u32 min_target;
        u32 aflags;
+       u64 allowed;
 };
 
 enum {

diff --git a/fs/gfs2/quota.c b/fs/gfs2/quota.c
index 964a769..5561468 100644 (file)
--- a/fs/gfs2/quota.c
+++ b/fs/gfs2/quota.c
@@ -1094,15 +1094,33 @@ static int print_message(struct gfs2_quota_data *qd, char *type)
        return 0;
 }
 
+/**
+ * gfs2_quota_check - check if allocating new blocks will exceed quota
+ * @ip:  The inode for which this check is being performed
+ * @uid: The uid to check against
+ * @gid: The gid to check against
+ * @ap:  The allocation parameters. ap->target contains the requested
+ *       blocks. ap->min_target, if set, contains the minimum blks
+ *       requested.
+ *
+ * Returns: 0 on success.
+ *                  min_req = ap->min_target ? ap->min_target : ap->target;
+ *                  quota must allow atleast min_req blks for success and
+ *                  ap->allowed is set to the number of blocks allowed
+ *
+ *          -EDQUOT otherwise, quota violation. ap->allowed is set to number
+ *                  of blocks available.
+ */
 int gfs2_quota_check(struct gfs2_inode *ip, kuid_t uid, kgid_t gid,
                     struct gfs2_alloc_parms *ap)
 {
        struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
        struct gfs2_quota_data *qd;
-       s64 value;
+       s64 value, warn, limit;
        unsigned int x;
        int error = 0;
 
+       ap->allowed = UINT_MAX; /* Assume we are permitted a whole lot */
        if (!test_bit(GIF_QD_LOCKED, &ip->i_flags))
                return 0;
 
@@ -1116,29 +1134,37 @@ int gfs2_quota_check(struct gfs2_inode *ip, kuid_t uid, kgid_t gid,
                      qid_eq(qd->qd_id, make_kqid_gid(gid))))
                        continue;
 
+               warn = (s64)be64_to_cpu(qd->qd_qb.qb_warn);
+               limit = (s64)be64_to_cpu(qd->qd_qb.qb_limit);
                value = (s64)be64_to_cpu(qd->qd_qb.qb_value);
                spin_lock(&qd_lock);
-               value += qd->qd_change + ap->target;
+               value += qd->qd_change;
                spin_unlock(&qd_lock);
 
-               if (be64_to_cpu(qd->qd_qb.qb_limit) && (s64)be64_to_cpu(qd->qd_qb.qb_limit) < value) {
-                       print_message(qd, "exceeded");
-                       quota_send_warning(qd->qd_id,
-                                          sdp->sd_vfs->s_dev, QUOTA_NL_BHARDWARN);
-                       error = -EDQUOT;
-                       break;
-               } else if (be64_to_cpu(qd->qd_qb.qb_warn) &&
-                          (s64)be64_to_cpu(qd->qd_qb.qb_warn) < value &&
+               if (limit > 0 && (limit - value) < ap->allowed)
+                       ap->allowed = limit - value;
+               /* If we can't meet the target */
+               if (limit && limit < (value + (s64)ap->target)) {
+                       /* If no min_target specified or we don't meet
+                        * min_target, return -EDQUOT */
+                       if (!ap->min_target || ap->min_target > ap->allowed) {
+                               print_message(qd, "exceeded");
+                               quota_send_warning(qd->qd_id,
+                                                  sdp->sd_vfs->s_dev,
+                                                  QUOTA_NL_BHARDWARN);
+                               error = -EDQUOT;
+                               break;
+                       }
+               } else if (warn && warn < value &&
                           time_after_eq(jiffies, qd->qd_last_warn +
-                                        gfs2_tune_get(sdp,
-                                               gt_quota_warn_period) * HZ)) {
+                                        gfs2_tune_get(sdp, gt_quota_warn_period)
+                                        * HZ)) {
                        quota_send_warning(qd->qd_id,
                                           sdp->sd_vfs->s_dev, QUOTA_NL_BSOFTWARN);
                        error = print_message(qd, "warning");
                        qd->qd_last_warn = jiffies;
                }
        }
-
        return error;
 }
 

diff --git a/fs/gfs2/rgrp.c b/fs/gfs2/rgrp.c
index 9150207..6af2396 100644 (file)
--- a/fs/gfs2/rgrp.c
+++ b/fs/gfs2/rgrp.c
@@ -1946,10 +1946,18 @@ static inline int fast_to_acquire(struct gfs2_rgrpd *rgd)
  * @ip: the inode to reserve space for
  * @ap: the allocation parameters
  *
- * Returns: errno
+ * We try our best to find an rgrp that has at least ap->target blocks
+ * available. After a couple of passes (loops == 2), the prospects of finding
+ * such an rgrp diminish. At this stage, we return the first rgrp that has
+ * atleast ap->min_target blocks available. Either way, we set ap->allowed to
+ * the number of blocks available in the chosen rgrp.
+ *
+ * Returns: 0 on success,
+ *          -ENOMEM if a suitable rgrp can't be found
+ *          errno otherwise
  */
 
-int gfs2_inplace_reserve(struct gfs2_inode *ip, const struct gfs2_alloc_parms *ap)
+int gfs2_inplace_reserve(struct gfs2_inode *ip, struct gfs2_alloc_parms *ap)
 {
        struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
        struct gfs2_rgrpd *begin = NULL;
@@ -2012,7 +2020,7 @@ int gfs2_inplace_reserve(struct gfs2_inode *ip, const struct gfs2_alloc_parms *a
                /* Skip unuseable resource groups */
                if ((rs->rs_rbm.rgd->rd_flags & (GFS2_RGF_NOALLOC |
                                                 GFS2_RDF_ERROR)) ||
-                   (ap->target > rs->rs_rbm.rgd->rd_extfail_pt))
+                   (loops == 0 && ap->target > rs->rs_rbm.rgd->rd_extfail_pt))
                        goto skip_rgrp;
 
                if (sdp->sd_args.ar_rgrplvb)
@@ -2027,11 +2035,13 @@ int gfs2_inplace_reserve(struct gfs2_inode *ip, const struct gfs2_alloc_parms *a
                        goto check_rgrp;
 
                /* If rgrp has enough free space, use it */
-               if (rs->rs_rbm.rgd->rd_free_clone >= ap->target) {
+               if (rs->rs_rbm.rgd->rd_free_clone >= ap->target ||
+                   (loops == 2 && ap->min_target &&
+                    rs->rs_rbm.rgd->rd_free_clone >= ap->min_target)) {
                        ip->i_rgd = rs->rs_rbm.rgd;
+                       ap->allowed = ip->i_rgd->rd_free_clone;
                        return 0;
                }
-
 check_rgrp:
                /* Check for unlinked inodes which can be reclaimed */
                if (rs->rs_rbm.rgd->rd_flags & GFS2_RDF_CHECK)

diff --git a/fs/gfs2/rgrp.h b/fs/gfs2/rgrp.h
index b104f4a..68972ec 100644 (file)
--- a/fs/gfs2/rgrp.h
+++ b/fs/gfs2/rgrp.h
@@ -41,7 +41,8 @@ extern void gfs2_rgrp_go_unlock(struct gfs2_holder *gh);
 extern struct gfs2_alloc *gfs2_alloc_get(struct gfs2_inode *ip);
 
 #define GFS2_AF_ORLOV 1
-extern int gfs2_inplace_reserve(struct gfs2_inode *ip, const struct gfs2_alloc_parms *ap);
+extern int gfs2_inplace_reserve(struct gfs2_inode *ip,
+                               struct gfs2_alloc_parms *ap);
 extern void gfs2_inplace_release(struct gfs2_inode *ip);
 
 extern int gfs2_alloc_blocks(struct gfs2_inode *ip, u64 *bn, unsigned int *n,