doc: The lock-ahead translator is not in tree, drop docs

Change-Id: Idda32338af416dc085c48ff023eeacf2397b65fd
Signed-off-by: Lubomir Rintel <lubo.rintel@gooddata.com>
Reviewed-on: http://review.gluster.org/5485
Reviewed-by: Vijay Bellur <vbellur@redhat.com>
Tested-by: Vijay Bellur <vbellur@redhat.com>

1 files changed, 0 insertions, 80 deletions

diff --git a/doc/legacy/hacker-guide/lock-ahead.txt b/doc/legacy/hacker-guide/lock-ahead.txt
deleted file mode 100644
index 70aa452d3de..00000000000
--- a/doc/legacy/hacker-guide/lock-ahead.txt
+++ /dev/null
@@ -1,80 +0,0 @@
-			Lock-ahead translator
-                        ---------------------
-
-The objective of the lock-ahead translator is to speculatively
-hold locks (inodelk and entrylk) on the universal set (0 - infinity
-in case of inodelk and all basenames in case of entrylk) even
-when a lock is requested only on a subset, in anticipation that
-further locks will be requested within the same universal set.
-
-So, for example, when cluster/replicate locks a region before
-writing to it, lock-ahead would instead lock the entire file.
-On further writes, lock-ahead can immediately return success for
-the lock requests, since the entire file has been previously locked.
-
-To avoid starvation of other clients/mountpoints, we employ a
-notify mechanism, described below.
-
-typedef struct {
-        struct list_head subset_locks;
-} la_universal_lock_t;
-
-Universal lock structure is stored in the inode context.
-
-typedef struct {
-	enum {LOCK_AHEAD_ENTRYLK, LOCK_AHEAD_FENTRYLK,
-              LOCK_AHEAD_INODELK, LOCK_AHEAD_FINODELK};
-
-        union {
-	      fd_t *fd;
-              loc_t loc;
-	};
-
-	off_t l_start;
-        off_t l_len;
-
-	const char *basename;
-
-	struct list_head universal_lock;
-} la_subset_lock_t;
-
-
-fops implemented:
-
-* inodelk/finodelk/entrylk/fentrylk:
-
-lock:
-  if universal lock held:
-    add subset to it (save loc_t or fd) and return success
-  else:
-    send lock-notify fop
-    hold universal lock and return
-      (set inode context, add subset to it, save loc_t or fd)
-
-    if this fails:
-      forward the lock request
-
-unlock:
-  if subset exists in universal lock:
-    delete subset lock from list
-  else:
-    forward it
-
-* release:
-    hold subset locks (each subset lock using the saved loc_t or fd)
-    and release universal lock
-
-* lock-notify (on unwind) (new fop)
-    hold subset locks and release universal lock
-
-
-lock-notify in locks translator:
-
-if a subset lock in entrylk/inodelk cannot be satisfied
-because of a universal lock held by someone else:
-    unwind the lock-notify fop
-
-==============================================
-$ Last updated: Tue Feb 17 11:31:18 IST 2009 $
-$ Author: Vikas Gorur <vikas@gluster.com>  $
-==============================================