copyonwrite-optimization-fix-20090325
authorRainer Toebbicke <rtb@pclella.cern.ch>
Wed, 25 Mar 2009 14:34:38 +0000 (14:34 +0000)
committerDerrick Brashear <shadow@dementia.org>
Wed, 25 Mar 2009 14:34:38 +0000 (14:34 +0000)
LICENSE IPL10

update to do tail case

src/viced/afsfileprocs.c

index e4e67e8..6890b8c 100644 (file)
@@ -1257,6 +1257,7 @@ CopyOnWrite2(FdHandle_t *targFdP, FdHandle_t *newFdP, afs_fsize_t off, afs_fsize
     FDH_SEEK(targFdP, off, SEEK_SET);
     FDH_SEEK(newFdP, off, SEEK_SET);
 
+    if (size > FDH_SIZE(targFdP) - off) size = FDH_SIZE(targFdP) - off;
     while (size > 0) {
        if (size > COPYBUFFSIZE) {      /* more than a buffer */
            length = COPYBUFFSIZE;
@@ -7203,7 +7204,7 @@ StoreData_RXStyle(Volume * volptr, Vnode * targetptr, struct AFSFid * Fid,
     afs_fsize_t NewLength;     /* size after this store completes */
     afs_sfsize_t adjustSize;   /* bytes to call VAdjust... with */
     int linkCount = 0;         /* link count on inode */
-    afs_fsize_t CoW_off = 0, CoW_len = 0;
+    afs_fsize_t CoW_off, CoW_len;
     FdHandle_t *fdP, *origfdP = NULL;
     struct in_addr logHostAddr;        /* host ip holder for inet_ntoa */
 
@@ -7274,18 +7275,15 @@ StoreData_RXStyle(Volume * volptr, Vnode * targetptr, struct AFSFid * Fid,
                return (errorCode);
            }
 
-           if (Pos == 0) 
-               CoW_off = Length;       /* only copy remaining parts of file */
-           if (Length <= FileLength)
-               CoW_len = FileLength - Length;
+           CoW_len = (FileLength >= (Length + Pos)) ? FileLength - Length : Pos;
            CopyOnWrite_calls++;
            if (CoW_len == 0) CopyOnWrite_size0++;
-           if (CoW_off == 0) CopyOnWrite_off0++;
+           if (Pos == 0) CopyOnWrite_off0++;
            if (CoW_len > CopyOnWrite_maxsize) CopyOnWrite_maxsize = CoW_len;
 
            ViceLog(1, ("StoreData : calling CopyOnWrite on vnode %lu.%lu (%s) off 0x%llx size 0x%llx\n",
-                       V_id(volptr), targetptr->vnodeNumber, V_name(volptr), CoW_off, CoW_len));
-           if ((errorCode = CopyOnWrite(targetptr, volptr, CoW_off, CoW_len))) {
+                       V_id(volptr), targetptr->vnodeNumber, V_name(volptr), 0, Pos));
+           if ((errorCode = CopyOnWrite(targetptr, volptr, 0, Pos))) {
                ViceLog(25, ("StoreData : CopyOnWrite failed\n"));
                volptr->partition->flags &= ~PART_DONTUPDATE;
                FDH_CLOSE(origfdP);
@@ -7426,7 +7424,7 @@ StoreData_RXStyle(Volume * volptr, Vnode * targetptr, struct AFSFid * Fid,
         */
        targetptr->changed_newTime = 1;
        if (origfdP && (bytesTransfered < Length))      /* Need to "finish" CopyOnWrite still */
-           CopyOnWrite2(origfdP, fdP, bytesTransfered, Length - bytesTransfered);
+           CopyOnWrite2(origfdP, fdP, Pos + bytesTransfered, NewLength - Pos - bytesTransfered);
        if (origfdP) FDH_CLOSE(origfdP);
        FDH_CLOSE(fdP);
        /* set disk usage to be correct */
@@ -7435,7 +7433,14 @@ StoreData_RXStyle(Volume * volptr, Vnode * targetptr, struct AFSFid * Fid,
                                         nBlocks(NewLength)), 0);
        return errorCode;
     }
-    if (origfdP) FDH_CLOSE(origfdP);
+    if (origfdP) {                                     /* finish CopyOnWrite */
+       if ( (CoW_off = Pos + Length) < NewLength) {
+           errorCode = CopyOnWrite2(origfdP, fdP, CoW_off, CoW_len = NewLength - CoW_off);
+           ViceLog(1, ("StoreData : CopyOnWrite2 on vnode %lu.%lu (%s) off 0x%llx size 0x%llx returns %d\n",
+                        V_id(volptr), targetptr->vnodeNumber, V_name(volptr), CoW_off, CoW_len, errorCode));
+       }
+       FDH_CLOSE(origfdP);
+    }
     FDH_CLOSE(fdP);
 
     FT_GetTimeOfDay(&StopTime, 0);