From 74e810c602a40d6c316f111cc1333c13bd5aec08 Mon Sep 17 00:00:00 2001
From: Pranith Kumar K <pkarampu@redhat.com>
Date: Tue, 10 Sep 2019 19:06:54 +0530
Subject: cluster/ec: Implement read-mask feature

fixes: #725
Change-Id: Iaaefe6f49c8193c476b987b92df6bab3e2f62601
Signed-off-by: Pranith Kumar K <pkarampu@redhat.com>
---
 xlators/cluster/ec/src/ec-inode-read.c |  4 ++
 xlators/cluster/ec/src/ec-types.h      |  1 +
 xlators/cluster/ec/src/ec.c            | 77 ++++++++++++++++++++++++++++++++++
 3 files changed, 82 insertions(+)

(limited to 'xlators/cluster')

diff --git a/xlators/cluster/ec/src/ec-inode-read.c b/xlators/cluster/ec/src/ec-inode-read.c
index 503149cf840..8f6c2aab1f1 100644
--- a/xlators/cluster/ec/src/ec-inode-read.c
+++ b/xlators/cluster/ec/src/ec-inode-read.c
@@ -1330,6 +1330,7 @@ int32_t
 ec_manager_readv(ec_fop_data_t *fop, int32_t state)
 {
     ec_cbk_data_t *cbk;
+    ec_t *ec = fop->xl->private;
 
     switch (state) {
         case EC_STATE_INIT:
@@ -1349,6 +1350,9 @@ ec_manager_readv(ec_fop_data_t *fop, int32_t state)
             return EC_STATE_DISPATCH;
 
         case EC_STATE_DISPATCH:
+            if (ec->read_mask) {
+                fop->mask &= ec->read_mask;
+            }
             ec_dispatch_min(fop);
 
             return EC_STATE_PREPARE_ANSWER;
diff --git a/xlators/cluster/ec/src/ec-types.h b/xlators/cluster/ec/src/ec-types.h
index 2568b6b3223..7829b8c27b3 100644
--- a/xlators/cluster/ec/src/ec-types.h
+++ b/xlators/cluster/ec/src/ec-types.h
@@ -646,6 +646,7 @@ struct _ec {
     uintptr_t xl_notify;      /* Bit flag representing
                                  notification for bricks. */
     uintptr_t node_mask;
+    uintptr_t read_mask;         /*Stores user defined read-mask*/
     gf_atomic_t async_fop_count; /* Number of on going asynchronous fops. */
     xlator_t **xl_list;
     gf_lock_t lock;
diff --git a/xlators/cluster/ec/src/ec.c b/xlators/cluster/ec/src/ec.c
index d91d77a4962..66b4e634911 100644
--- a/xlators/cluster/ec/src/ec.c
+++ b/xlators/cluster/ec/src/ec.c
@@ -702,6 +702,67 @@ ec_statistics_init(ec_t *ec)
     GF_ATOMIC_INIT(ec->stats.stripe_cache.errors, 0);
 }
 
+static int
+ec_assign_read_mask(ec_t *ec, char *read_mask_str)
+{
+    char *mask = NULL;
+    char *maskptr = NULL;
+    char *saveptr = NULL;
+    char *id_str = NULL;
+    int id = 0;
+    int ret = 0;
+    uintptr_t read_mask = 0;
+
+    if (!read_mask_str) {
+        ec->read_mask = 0;
+        ret = 0;
+        goto out;
+    }
+
+    mask = gf_strdup(read_mask_str);
+    if (!mask) {
+        ret = -1;
+        goto out;
+    }
+    maskptr = mask;
+
+    for (;;) {
+        id_str = strtok_r(maskptr, ":", &saveptr);
+        if (id_str == NULL)
+            break;
+        if (gf_string2int(id_str, &id)) {
+            gf_msg(ec->xl->name, GF_LOG_ERROR, 0, EC_MSG_XLATOR_INIT_FAIL,
+                   "In read-mask \"%s\" id %s is not a valid integer",
+                   read_mask_str, id_str);
+            ret = -1;
+            goto out;
+        }
+
+        if ((id < 0) || (id >= ec->nodes)) {
+            gf_msg(ec->xl->name, GF_LOG_ERROR, 0, EC_MSG_XLATOR_INIT_FAIL,
+                   "In read-mask \"%s\" id %d is not in range [0 - %d]",
+                   read_mask_str, id, ec->nodes - 1);
+            ret = -1;
+            goto out;
+        }
+        read_mask |= (1UL << id);
+        maskptr = NULL;
+    }
+
+    if (gf_bits_count(read_mask) < ec->fragments) {
+        gf_msg(ec->xl->name, GF_LOG_ERROR, 0, EC_MSG_XLATOR_INIT_FAIL,
+               "read-mask \"%s\" should contain at least %d ids", read_mask_str,
+               ec->fragments);
+        ret = -1;
+        goto out;
+    }
+    ec->read_mask = read_mask;
+    ret = 0;
+out:
+    GF_FREE(mask);
+    return ret;
+}
+
 int32_t
 init(xlator_t *this)
 {
@@ -709,6 +770,7 @@ init(xlator_t *this)
     char *read_policy = NULL;
     char *extensions = NULL;
     int32_t err;
+    char *read_mask_str = NULL;
 
     if (this->parents == NULL) {
         gf_msg(this->name, GF_LOG_WARNING, 0, EC_MSG_NO_PARENTS,
@@ -796,6 +858,10 @@ init(xlator_t *this)
     GF_OPTION_INIT("parallel-writes", ec->parallel_writes, bool, failed);
     GF_OPTION_INIT("stripe-cache", ec->stripe_cache, uint32, failed);
     GF_OPTION_INIT("quorum-count", ec->quorum_count, uint32, failed);
+    GF_OPTION_INIT("ec-read-mask", read_mask_str, str, failed);
+
+    if (ec_assign_read_mask(ec, read_mask_str))
+        goto failed;
 
     this->itable = inode_table_new(EC_SHD_INODE_LRU_LIMIT, this);
     if (!this->itable)
@@ -1471,6 +1537,10 @@ ec_dump_private(xlator_t *this)
     gf_proc_dump_write("childs_up", "%u", ec->xl_up_count);
     gf_proc_dump_write("childs_up_mask", "%s",
                        ec_bin(tmp, sizeof(tmp), ec->xl_up, ec->nodes));
+    if (ec->read_mask) {
+        gf_proc_dump_write("read-mask", "%s",
+                           ec_bin(tmp, sizeof(tmp), ec->read_mask, ec->nodes));
+    }
     gf_proc_dump_write("background-heals", "%d", ec->background_heals);
     gf_proc_dump_write("heal-wait-qlength", "%d", ec->heal_wait_qlen);
     gf_proc_dump_write("self-heal-window-size", "%" PRIu32,
@@ -1759,6 +1829,13 @@ struct volume_options options[] = {
             " count should be in the range"
             "[disperse-data-count,  disperse-count] (inclusive)",
     },
+    {
+        .key = {"ec-read-mask"},
+        .type = GF_OPTION_TYPE_STR,
+        .default_value = NULL,
+        .description = "This option can be used to choose which bricks can be"
+                       " used for reading data/metadata of a file/directory",
+    },
     {
         .key = {NULL},
     },
-- 
cgit