Avoid unnecessarily updating .. in SAFSS_Rename

Currently the .. entry for a directory is always recreated on a Rename
operation, even if the parent directory does not change. Now, avoid
altering the directory at all (including no COW nor DV bump nor vnode
modify time update) when we don't need to.

Change-Id: I53478ec05e2fc6362836043476ff67e2c41b7feb
Reviewed-on: http://gerrit.openafs.org/436
Reviewed-by: Derrick Brashear <shadow@dementia.org>
Tested-by: Derrick Brashear <shadow@dementia.org>

diff --git a/src/viced/afsfileprocs.c b/src/viced/afsfileprocs.c
index 6b524d4258ee5a797dff918e6d91c7783aa90cc4..7352a93e3d6e8e713482ca9d98802b8596d823d5 100644 (file)
--- a/src/viced/afsfileprocs.c
+++ b/src/viced/afsfileprocs.c
@@ -3847,6 +3847,8 @@ SAFSS_Rename(struct rx_call *acall, struct AFSFid *OldDirFid, char *OldName,
     afs_int32 newanyrights;    /* rights for any user */
     int doDelete;              /* deleted the rename target (ref count now 0) */
     int code;
+    int updatefile = 0;                /* are we changing the renamed file? (we do this
+                                * if we need to update .. on a renamed dir) */
     struct client *t_client;   /* tmp ptr to client data */
     struct in_addr logHostAddr;        /* host ip holder for inet_ntoa */
     struct rx_connection *tcon = rx_ConnectionOf(acall);
@@ -4088,10 +4090,28 @@ SAFSS_Rename(struct rx_call *acall, struct AFSFid *OldDirFid, char *OldName,
            assert(errorCode == 0);
        }
     }
+
+    if (fileptr->disk.type == vDirectory) {
+       SetDirHandle(&filedir, fileptr);
+       if (oldvptr != newvptr) {
+           /* we always need to update .. if we've moving fileptr to a
+            * different directory */
+           updatefile = 1;
+       } else {
+           struct AFSFid unused;
+
+           code = Lookup(&filedir, "..", &unused);
+           if (code == ENOENT) {
+               /* only update .. if it doesn't already exist */
+               updatefile = 1;
+           }
+       }
+    }
+
     /* Do the CopyonWrite first before modifying anything else. Copying is
-     *  required because we may have to change entries for .. 
+     * required when we have to change entries for ..
      */
-    if ((fileptr->disk.type == vDirectory) && (fileptr->disk.cloned)) {
+    if (updatefile && (fileptr->disk.cloned)) {
        ViceLog(25, ("Rename : calling CopyOnWrite on  target dir\n"));
        if ((errorCode = CopyOnWrite(fileptr, volptr, 0, MAXFSIZE)))
            goto Bad_Rename;
@@ -4167,17 +4187,23 @@ SAFSS_Rename(struct rx_call *acall, struct AFSFid *OldDirFid, char *OldName,
     if (oldvptr == newvptr)
        oldvptr->disk.dataVersion--;    /* Since it was bumped by 2! */
 
-    fileptr->disk.parent = newvptr->vnodeNumber;
-    fileptr->changed_newTime = 1;      /* status change of moved file */
+    if (fileptr->disk.parent != newvptr->vnodeNumber) {
+       fileptr->disk.parent = newvptr->vnodeNumber;
+       fileptr->changed_newTime = 1;
+    }
 
-    /* if we are dealing with a rename of a directory */
-    if (fileptr->disk.type == vDirectory) {
+    /* if we are dealing with a rename of a directory, and we need to
+     * update the .. entry of that directory */
+    if (updatefile) {
        assert(!fileptr->disk.cloned);
-       SetDirHandle(&filedir, fileptr);
+
+       fileptr->changed_newTime = 1;   /* status change of moved file */
+
        /* fix .. to point to the correct place */
        Delete(&filedir, ".."); /* No assert--some directories may be bad */
        assert(Create(&filedir, "..", NewDirFid) == 0);
        fileptr->disk.dataVersion++;
+
        /* if the parent directories are different the link counts have to be   */
        /* changed due to .. in the renamed directory */
        if (oldvptr != newvptr) {
@@ -4212,8 +4238,10 @@ SAFSS_Rename(struct rx_call *acall, struct AFSFid *OldDirFid, char *OldName,
     BreakCallBack(client->host, NewDirFid, 0);
     if (oldvptr != newvptr) {
        BreakCallBack(client->host, OldDirFid, 0);
-       if (fileptr->disk.type == vDirectory)   /* if a dir moved, .. changed */
-           BreakCallBack(client->host, &fileFid, 0);
+    }
+    if (updatefile) {
+       /* if a dir moved, .. changed */
+       BreakCallBack(client->host, &fileFid, 0);
     }
     if (newfileptr) {
        /* Note:  it is not necessary to break the callback */