distribute: add hash-name-regex option

This is to support the common "write to temp file then rename" idiom. In our
case this causes us to create a linkfile during the rename in (N-1)/N cases,
with a significant impact on performance e.g. for UFO which uses this idiom.
This patch allows the user to specify up to two regular expressions that
separate the permanent and transient parts of a temp-file name:

    rsync-hash-regex reimplements the existing RSYNC_FRIENDLY_NAME
    pattern where the temporary name for EXAMPLE is .EXAMPLE.suffix

    extra-hash-regex can be used for a second pattern, active concurrently,
    and can include alternatives via the POSIX extended-regex syntax

Change-Id: Ic1a6ed19324bc31fefe91ee34b8478877a9c5d2c
BUG: 912564
Signed-off-by: Jeff Darcy <jdarcy@redhat.com>
Reviewed-on: http://review.gluster.org/4116
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Anand Avati <avati@redhat.com>

1 files changed, 9 insertions, 1 deletions

diff --git a/xlators/cluster/dht/src/dht-common.h b/xlators/cluster/dht/src/dht-common.h
index 8f266ef8e..bd00089fc 100644
--- a/xlators/cluster/dht/src/dht-common.h
+++ b/xlators/cluster/dht/src/dht-common.h
@@ -13,6 +13,8 @@
 #include "config.h"
 #endif
 
+#include <regex.h>
+
 #include "dht-mem-types.h"
 #include "libxlator.h"
 #include "syncop.h"
@@ -275,6 +277,12 @@ struct dht_conf {
         /* Request to filter directory entries in readdir request */
 
         gf_boolean_t    readdir_optimize;
+
+        /* Support regex-based name reinterpretation. */
+        regex_t         rsync_regex;
+        gf_boolean_t    rsync_regex_valid;
+        regex_t         extra_regex;
+        gf_boolean_t    extra_regex_valid;
 };
 typedef struct dht_conf dht_conf_t;
 
@@ -420,7 +428,7 @@ xlator_t *dht_subvol_get_cached (xlator_t *this, inode_t *inode);
 xlator_t *dht_subvol_next (xlator_t *this, xlator_t *prev);
 int       dht_subvol_cnt (xlator_t *this, xlator_t *subvol);
 
-int dht_hash_compute (int type, const char *name, uint32_t *hash_p);
+int dht_hash_compute (xlator_t *this, int type, const char *name, uint32_t *hash_p);
 
 int dht_linkfile_create (call_frame_t    *frame, fop_mknod_cbk_t linkfile_cbk,
                          xlator_t        *tovol, xlator_t *fromvol, loc_t *loc);