r3056: added a id -> pointer data structure (a type of radix tree). This is

an extremely efficient way of mapping from an integer handle (such as
an open file handle) to a pointer (such as the structure containing
the open file information). The code is taken from lib/idr.c in the
2.6 Linux kernel, and is very fast and space efficient. By using
talloc it even has auto cleanup.

This commit converts the handling of open file handles and open
directory search handles to use the idtree routines. In combination
with talloc destructors, this simplifies the structure handling in the
pvfs backend a lot. For example, we no longer need to keep a linked
list of open directory searches at all, and we no longer need to do
linear scans of the list of open files on most operations.

The end result is that the pvfs code is now extremely scalable. You
can have 10s of thousands of open files and open searches and the code
still runs very fast.

I have also added a small optimisation into the file close path, to
avoid looking in the byte range locking database if we know that there
are no locks outstanding.
(This used to be commit 16835a0ef91a16fa01145b773aad8d43da215dbf)

1 files changed, 33 insertions, 30 deletions

diff --git a/source4/ntvfs/posix/pvfs_open.c b/source4/ntvfs/posix/pvfs_open.c
index 429f519bca..c255558369 100644
--- a/source4/ntvfs/posix/pvfs_open.c
+++ b/source4/ntvfs/posix/pvfs_open.c
@@ -31,16 +31,19 @@ struct pvfs_file *pvfs_find_fd(struct pvfs_state *pvfs,
 			       struct smbsrv_request *req, uint16_t fnum)
 {
 	struct pvfs_file *f;
-	for (f=pvfs->open_files;f;f=f->next) {
-		if (f->fnum == fnum) {
-			if (req->session != f->session) {
-				DEBUG(2,("pvfs_find_fd: attempt to use wrong session for fnum %d\n", fnum));
-				return NULL;
-			}
-			return f;
-		}
+
+	f = idr_find(pvfs->idtree_fnum, fnum);
+	if (f == NULL) {
+		return NULL;
 	}
-	return NULL;
+
+	if (req->session != f->session) {
+		DEBUG(2,("pvfs_find_fd: attempt to use wrong session for fnum %d\n", 
+			 fnum));
+		return NULL;
+	}
+
+	return f;
 }
 
 /*
@@ -52,14 +55,15 @@ static int pvfs_fd_destructor(void *p)
 {
 	struct pvfs_file *f = p;
 
-	pvfs_lock_close_pending(f->pvfs, f);
-
-	brl_close(f->pvfs->brl_context, &f->locking_key, f->fnum);
+	pvfs_lock_close(f->pvfs, f);
 
 	if (f->fd != -1) {
 		close(f->fd);
 		f->fd = -1;
 	}
+
+	idr_remove(f->pvfs->idtree_fnum, f->fnum);
+
 	return 0;
 }
 
@@ -80,6 +84,7 @@ NTSTATUS pvfs_open(struct ntvfs_module_context *ntvfs,
 		dev_t device;
 		ino_t inode;
 	} lock_context;
+	int fnum;
 
 	if (io->generic.level != RAW_OPEN_GENERIC) {
 		return ntvfs_map_open(req, io, ntvfs);
@@ -147,6 +152,17 @@ NTSTATUS pvfs_open(struct ntvfs_module_context *ntvfs,
 		}
 	}
 
+	f = talloc_p(pvfs, struct pvfs_file);
+	if (f == NULL) {
+		return NT_STATUS_NO_MEMORY;
+	}
+
+	fnum = idr_get_new(pvfs->idtree_fnum, f, 0x10000);
+	if (fnum == -1) {
+		talloc_free(f);
+		return NT_STATUS_TOO_MANY_OPENED_FILES;
+	}
+
 do_open:
 	fd = open(name->full_name, flags, 0644);
 	if (fd == -1) {
@@ -155,25 +171,20 @@ do_open:
 		return pvfs_map_errno(pvfs,errno);
 	}
 
-	f = talloc_p(pvfs, struct pvfs_file);
-	if (f == NULL) {
-		close(fd);
-		return NT_STATUS_NO_MEMORY;
-	}
-
 	/* re-resolve the open fd */
 	status = pvfs_resolve_name_fd(pvfs, fd, name);
 	if (!NT_STATUS_IS_OK(status)) {
 		return status;
 	}
 
-	f->fnum = fd;
+	f->fnum = fnum;
 	f->fd = fd;
 	f->name = talloc_steal(f, name);
 	f->session = req->session;
 	f->smbpid = req->smbpid;
 	f->pvfs = pvfs;
 	f->pending_list = NULL;
+	f->lock_count = 0;
 
 	/* we must zero here to take account of padding */
 	ZERO_STRUCT(lock_context);
@@ -223,22 +234,16 @@ NTSTATUS pvfs_close(struct ntvfs_module_context *ntvfs,
 		return NT_STATUS_INVALID_HANDLE;
 	}
 
-	pvfs_lock_close_pending(pvfs, f);
-
-	status = brl_close(pvfs->brl_context, &f->locking_key, f->fnum);
-	if (!NT_STATUS_IS_OK(status)) {
-		return status;
-	}
-
 	if (close(f->fd) != 0) {
 		status = pvfs_map_errno(pvfs, errno);
 	} else {
 		status = NT_STATUS_OK;
 	}
-
-	talloc_set_destructor(f, NULL);
+	f->fd = -1;
 
 	DLIST_REMOVE(pvfs->open_files, f);
+
+	/* the destructor takes care of the rest */
 	talloc_free(f);
 
 	return status;
@@ -257,7 +262,6 @@ NTSTATUS pvfs_logoff(struct ntvfs_module_context *ntvfs,
 	for (f=pvfs->open_files;f;f=next) {
 		next = f->next;
 		if (f->session == req->session) {
-			talloc_set_destructor(f, NULL);
 			DLIST_REMOVE(pvfs->open_files, f);
 			talloc_free(f);
 		}
@@ -279,7 +283,6 @@ NTSTATUS pvfs_exit(struct ntvfs_module_context *ntvfs,
 	for (f=pvfs->open_files;f;f=next) {
 		next = f->next;
 		if (f->smbpid == req->smbpid) {
-			talloc_set_destructor(f, NULL);
 			DLIST_REMOVE(pvfs->open_files, f);
 			talloc_free(f);
 		}