adds freed blocks to the free list

CVS patchset: 447
CVS date: 1996/03/01 03:28:55

diff --git a/lib/falloc.c b/lib/falloc.c
index 661d947..ec2d2be 100644 (file)
--- a/lib/falloc.c
+++ b/lib/falloc.c
@@ -117,6 +117,8 @@ unsigned int faAlloc(faFile fa, unsigned int size) { /* returns 0 on failure */
     (size % 64) ? size += (64 - (size % 64)) : 0;
 
     /* find a block via first fit - see Knuth vol 1 for why */
+    /* XXX this could be optimized a bit still */
+
     nextFreeBlock =  fa->firstFree;
     newBlockOffset = 0;
 
@@ -125,7 +127,7 @@ unsigned int faAlloc(faFile fa, unsigned int size) { /* returns 0 on failure */
        if (read(fa->fd, &header, sizeof(header)) != sizeof(header)) return 0;
 
        if (!header.isFree) {
-           fprintf(stderr, "free list corrupt");
+           fprintf(stderr, "free list corrupt - contact support@redhat.com");
            exit(1);
        }
 
@@ -137,9 +139,7 @@ unsigned int faAlloc(faFile fa, unsigned int size) { /* returns 0 on failure */
     }
 
     if (newBlockOffset) {
-       if (lseek(fa->fd, newBlockOffset, SEEK_SET) < 0) return 0;
-       if (read(fa->fd, &header, sizeof(header)) != sizeof(header)) 
-           return 0;
+       /* header should still be good from the search */
        origHeader = header;
 
        footerOffset = newBlockOffset + header.size - sizeof(footer);
@@ -150,7 +150,6 @@ unsigned int faAlloc(faFile fa, unsigned int size) { /* returns 0 on failure */
        origFooter = footer;
 
        /* should we split this block into two? */
-
        /* XXX implement fragment creation here */
 
        footer.isFree = header.isFree = 0;
@@ -159,6 +158,7 @@ unsigned int faAlloc(faFile fa, unsigned int size) { /* returns 0 on failure */
        if (newBlockOffset == fa->firstFree) {
            faHeader.magic = FA_MAGIC;
            faHeader.firstFree = header.freeNext;
+           updateHeader = 1;
        } else {
            if (lseek(fa->fd, header.freePrev, SEEK_SET) < 0) return 0;
            if (read(fa->fd, &prevFreeHeader, sizeof(prevFreeHeader)) !=
@@ -296,13 +296,39 @@ void faFree(faFile fa, unsigned int offset) {
     struct faHeader header;
     struct faFooter footer;
     int footerOffset;
+    int prevFreeOffset, nextFreeOffset;
+    struct faHeader prevFreeHeader, nextFreeHeader;
+    struct faFileHeader faHeader;
 
     /* any errors cause this to die, and thus result in lost space in the
        database. which is at least better then corruption */
 
     offset -= sizeof(header);
 
-    /* for now, just add it to the free list */
+    /* find out where in the (sorted) free list to put this */
+    prevFreeOffset = fa->firstFree;
+
+    while (prevFreeOffset) {
+       if (lseek(fa->fd, prevFreeOffset, SEEK_SET) < 0) return;
+       if (read(fa->fd, &prevFreeHeader, sizeof(prevFreeHeader)) != 
+               sizeof(prevFreeHeader)) return;
+
+       if (prevFreeHeader.freeNext > offset || !prevFreeHeader.freeNext)
+           break;
+       else
+           prevFreeOffset = prevFreeHeader.freeNext;
+    }
+
+    if (prevFreeOffset)
+       nextFreeOffset = prevFreeHeader.freeNext;
+    else
+       nextFreeOffset = fa->firstFree;
+
+    if (nextFreeOffset) {
+       if (lseek(fa->fd, nextFreeOffset, SEEK_SET) < 0) return;
+       if (read(fa->fd, &nextFreeHeader, sizeof(nextFreeHeader)) != 
+               sizeof(nextFreeHeader)) return;
+    }
 
     if (lseek(fa->fd, offset, SEEK_SET) < 0)
        return;
@@ -313,10 +339,12 @@ void faFree(faFile fa, unsigned int offset) {
 
     if (lseek(fa->fd, footerOffset, SEEK_SET) < 0)
        return;
-    if (read(fa->fd, &header, sizeof(header)) != sizeof(header))
+    if (read(fa->fd, &footer, sizeof(footer)) != sizeof(footer))
        return;
 
     header.isFree = 1;
+    header.freeNext = nextFreeOffset;
+    header.freePrev = prevFreeOffset;
     footer.isFree = 1;
 
     lseek(fa->fd, offset, SEEK_SET);
@@ -325,7 +353,26 @@ void faFree(faFile fa, unsigned int offset) {
     lseek(fa->fd, footerOffset, SEEK_SET);
     write(fa->fd, &footer, sizeof(footer));
 
-    return;
+    if (nextFreeOffset) {
+       nextFreeHeader.freePrev = offset;
+       if (lseek(fa->fd, nextFreeOffset, SEEK_SET) < 0) return;
+       if (write(fa->fd, &nextFreeHeader, sizeof(nextFreeHeader)) != 
+               sizeof(nextFreeHeader)) return;
+    }
+
+    if (prevFreeOffset) {
+       prevFreeHeader.freeNext = offset;
+       if (lseek(fa->fd, prevFreeOffset, SEEK_SET) < 0) return;
+       write(fa->fd, &prevFreeHeader, sizeof(prevFreeHeader));
+    } else {
+       fa->firstFree = offset;
+
+       faHeader.magic = FA_MAGIC;
+       faHeader.firstFree = fa->firstFree;
+
+       if (lseek(fa->fd, 0, SEEK_SET) < 0) return;
+       write(fa->fd, &faHeader, sizeof(faHeader));
+    }
 }
 
 void faClose(faFile fa) {