cluster/ec: Fix readdir de-itransform

Problem:
gf_deitransform returns the glbal client-id in the complete graph. So except
for the first disperse subvolume under dht, all the other disperse subvolumes
will return a client-id greater than ec->nodes, so readdir will always error
out in those subvolumes.

Fix:
Get the client subvolume whose client-id matches the client-id returned by
gf_deitransform of offset.

Change-Id: I26aa17504352d48d7ff14b390b62f49d7ab2d699
BUG: 1209113
Signed-off-by: Pranith Kumar K <pkarampu@redhat.com>
Reviewed-on: http://review.gluster.org/10165
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Xavier Hernandez <xhernandez@datalab.es>

1 files changed, 26 insertions, 8 deletions

diff --git a/xlators/cluster/ec/src/ec-dir-read.c b/xlators/cluster/ec/src/ec-dir-read.c
index 17e1a3d124e..ffc3ed5a7cd 100644
--- a/xlators/cluster/ec/src/ec-dir-read.c
+++ b/xlators/cluster/ec/src/ec-dir-read.c
@@ -296,6 +296,30 @@ out:
     }
 }
 
+/* Returns -1 if client_id is invalid else index of child subvol in xl_list */
+int
+ec_deitransform (xlator_t *this, off_t offset)
+{
+        int  idx       = -1;
+        int  client_id = -1;
+        ec_t *ec       = this->private;
+        char id[32]    = {0};
+
+        client_id = gf_deitransform (this, offset);
+        sprintf (id, "%d", client_id);
+        if (dict_get_int32 (ec->leaf_to_subvolid, id, &idx)) {
+                idx = -1;
+                goto out;
+        }
+
+out:
+        if (idx < 0) {
+                gf_log (this->name, GF_LOG_ERROR,
+                        "Invalid index %d in readdirp request", client_id);
+        }
+        return idx;
+}
+
 /* FOP: readdir */
 
 void ec_adjust_readdir(ec_t * ec, int32_t idx, gf_dirent_t * entries)
@@ -412,17 +436,11 @@ int32_t ec_manager_readdir(ec_fop_data_t * fop, int32_t state)
             if (fop->offset != 0)
             {
                 int32_t idx = -1;
-                ec_t    *ec = fop->xl->private;
-
-                idx = gf_deitransform(fop->xl, fop->offset);
 
-                if ((idx < 0) || (idx >= ec->nodes)) {
-
-                        gf_log(fop->xl->name, GF_LOG_ERROR,
-                               "Invalid index %d in readdirp request", idx);
+                idx = ec_deitransform (fop->xl, fop->offset);
 
+                if (idx < 0) {
                         fop->error = EIO;
-
                         return EC_STATE_REPORT;
                 }
                 fop->mask &= 1ULL << idx;