Correct free size calculation

When clearchain or trunc, move the fatcache to rb_free_root tree.
This way writefat will generate correct FAT table.
When clearchain or trunc, re-calculate the free sectors of
filesystem.

Change-Id: I3b480ab161db5777e6f948f780b6bdaf3ada9467

5 files changed, 84 insertions, 28 deletions

diff --git a/dir.c b/dir.c
index 2d52492..0b26fd4 100644
--- a/dir.c
+++ b/dir.c
@@ -476,7 +476,7 @@ checksize(struct bootblock *boot, u_char *p,
 			//TODO: i don't no why exec clearchain here.when cl != fat.head,clear do nothing
 			//clearchain(boot, fat,cl);
 			//if trunc it ,when next fsck ,the rest will locate in LOST.DIR
-			Trunc(fat,cl);
+			Trunc(boot,fat,cl);
 			fsck_debug("after truncate ,fat->length = %d \n",fat->length);
 			return FSFATMOD;
 		} else
@@ -840,7 +840,7 @@ readDosDirSection(int f, struct bootblock *boot,
 						tofind.head = dirent.head;
 						c_fat = RB_FIND(FSCK_MSDOS_CACHE,&rb_root,&tofind);
 						if(c_fat)
-							clearchain(c_fat, dirent.head);
+							clearchain(boot,c_fat, dirent.head);
 						else
 							mod |= FSERROR;
 						dirent.head = 0;
diff --git a/ext.h b/ext.h
index 17f5326..05e8c96 100644
--- a/ext.h
+++ b/ext.h
@@ -143,5 +143,5 @@ char *rsrvdcltype(cl_t);
 /*
  * Clear a cluster chain in a FAT
  */
-void clearchain(struct cluster_chain_descriptor *, cl_t);
+void clearchain(struct bootblock *,struct cluster_chain_descriptor *, cl_t);
 #endif
diff --git a/fat.c b/fat.c
index 73725be..b5a3302 100644
--- a/fat.c
+++ b/fat.c
@@ -52,7 +52,7 @@ static const char rcsid[] =
 #include "fragment.h"
 static int checkclnum(struct bootblock *, cl_t, cl_t *);
 static int clustdiffer(cl_t, cl_t *, cl_t *, int,int *);
-static int tryclear(struct cluster_chain_descriptor *, cl_t, cl_t *);
+static int tryclear(struct bootblock* ,struct cluster_chain_descriptor *, cl_t, cl_t *);
 int _readfat(int, struct bootblock *, int, u_char **);
 
 static cl_t firstfreecl = 0xFFFFFFFF;
@@ -360,11 +360,12 @@ int checkfat(int fs, struct bootblock *boot, int no,u_char *buffer)
 				p = buffer + 3*(nextclus/2);
 				break;
 			}
-			ret = checkclnum(boot,prevcl,&nextclus);
-			if(ret == FSERROR)
+			err = checkclnum(boot,prevcl,&nextclus);
+			ret |= err;
+			if(err & FSERROR)
 				return -1;
 			//truncate the rest clusters
-			if(ret == FSFATMOD)
+			if(err &  FSFATMOD)
 				break;
 			len++;
 			/*
@@ -388,14 +389,14 @@ int checkfat(int fs, struct bootblock *boot, int no,u_char *buffer)
 				fsck_warn("Cluster chain starting at %u ends with cluster marked %s,cl = %d ,nextclus = %d\n",cl,rsrvdcltype(nextclus),cl,nextclus);
 				SET_BIT(fat_bitmap[prevcl/32],prevcl%32);
 				/*if the next cluster is free or reversed ,just clear the existing cluster chain ,let this free or reversed cluster alone*/
-				ret |= tryclear(fat,cl,&prevcl);
+				ret |= tryclear(boot,fat,cl,&prevcl);
 				break;
 			}
 			/*out of range*/
 			if(nextclus < CLUST_FIRST ||(( nextclus >= boot->NumClusters) && (nextclus < (CLUST_EOFS & boot->ClustMask)))){
 				fsck_warn("Clusters chain starting at %u ends with cluster out of range (%u) \n",cl,nextclus);
 				SET_BIT(fat_bitmap[prevcl/32],prevcl%32);
-				ret |= tryclear(fat,cl,&prevcl);
+				ret |= tryclear(boot,fat,cl,&prevcl);
 				break;
 			}
 
@@ -471,7 +472,7 @@ int checkfat(int fs, struct bootblock *boot, int no,u_char *buffer)
 					 *because i handle fat chain by chain here,
 					 *it never appear  situation  that three or more cluster chains linked
 					 */
-					ret |= tryclear(fat,cl,&prevcl);
+					ret |= tryclear(boot,fat,cl,&prevcl);
 					break;
 				}
 			}
@@ -732,19 +733,42 @@ comparefat(struct bootblock *boot, u_char*first, u_char  *second, int fatnum)
 }
 
 void
-clearchain(struct cluster_chain_descriptor *fat, cl_t head)
-{
+clearchain(struct bootblock *boot,struct cluster_chain_descriptor *fat, cl_t head)
+ {
+	struct fatcache * curr,*next;
+	struct fragment *frag, *insert;
+
 	fsck_debug("%s:fat:%p , head(%d) ,length(%d)\n",__func__,fat,fat->head,fat->length);
 	assert(fat);
 	if(fat->head != head)
-		return ;
+		return;
+	/*re-calc free blocks*/
+	boot->NumFree += fat->length;
+	/*move to free tree for writefat()*/
+	curr = fat->child;
+	while(curr){
+		next = curr->next;
+		frag = New_fragment();
+		if(!frag){
+			fsck_warn("%s: No space left\n",__func__);
+			goto free;
+		}
+		frag->head = curr->head;
+		frag->length = curr->length;
+		insert = RB_INSERT(FSCK_MSDOS_FRAGMENT,&rb_free_root,frag);
+		if(insert)
+			fsck_warn("%s:fragment(head:0x%x) exist\n",__func__,frag->head);
+free:
+		free(curr);
+		curr = next;
+	}
 	/*must remove from rb tree before free*/
 	RB_REMOVE(FSCK_MSDOS_CACHE,&rb_root,fat);
 	free(fat);
 }
 
 int
-tryclear(struct cluster_chain_descriptor *fat, cl_t head, cl_t *trunc)
+tryclear(struct bootblock* boot, struct cluster_chain_descriptor *fat, cl_t head, cl_t *trunc)
 {
 	fsck_debug("fat:%p ,head :%d ,trunc :%d \n",fat,head,*trunc);
 	if(!fat || !trunc){
@@ -752,10 +776,10 @@ tryclear(struct cluster_chain_descriptor *fat, cl_t head, cl_t *trunc)
 		return FSERROR;
 	}
 	if (ask(1, "Clear chain starting at %u", head)) {
-		clearchain(fat, head);
+		clearchain(boot,fat, head);
 		return FSFATMOD;
 	} else if (ask(1, "Truncate")) {
-		Trunc(fat,*trunc);
+		Trunc(boot,fat,*trunc);
 		return FSFATMOD;
 	} else
 		return FSERROR;
@@ -817,7 +841,7 @@ writefat(int fs, struct bootblock *boot, int correct_fat)
 			break;
 		}
 
-		if (!_readfat(fs, boot, boot->ValidFat >= 0 ? boot->ValidFat :0,
+		if (_readfat(fs, boot, boot->ValidFat >= 0 ? boot->ValidFat :0,
 					 &old_fat)) {
 			free(buffer);
 			return FSFATAL;
@@ -907,13 +931,13 @@ checklost(int dosfs, struct bootblock *boot)
 			/* If the reconnect failed, then just clear the chain */
 			pwarn("Error reconnecting chain - clearing\n");
 			mod &= ~FSFATAL;
-			clearchain(fat,fat->head);
+			clearchain(boot,fat,fat->head);
 			mod |= FSFATMOD;
 			fat  = RB_NEXT(FSCK_MSDOS_CACHE,0,fat);
 			continue;
 		}
 		if (ret == FSERROR && ask(1, "Clear")) {
-			clearchain(fat, fat->head);
+			clearchain(boot, fat, fat->head);
 			mod |= FSFATMOD;
 		}
 		fat  = RB_NEXT(FSCK_MSDOS_CACHE,0,fat);
diff --git a/fatcache.c b/fatcache.c
index 4d1e1a6..5b9a73b 100644
--- a/fatcache.c
+++ b/fatcache.c
@@ -29,6 +29,7 @@
 #include "dosfs.h"
 #include "ext.h"
 #include "fatcache.h"
+#include "fragment.h"
 #include "fsutil.h"
 #include <stdio.h>
 #include <unistd.h>
@@ -287,6 +288,8 @@ struct fatcache* Find_nextclus(struct cluster_chain_descriptor* fat,unsigned int
 int delete_fatcache_below(struct cluster_chain_descriptor * fatentry,struct fatcache*cache)
 {
 	struct fatcache *curr = cache,*next,*last;
+	struct fragment *frag,*insert;
+
 	last = cache;
 	if(!cache || !fatentry){
 		fsck_warn("%s:NULL pointer\n",__func__);
@@ -299,6 +302,18 @@ int delete_fatcache_below(struct cluster_chain_descriptor * fatentry,struct fatc
 		curr = next;
 		next = next->next;
 		fatentry->length -= curr->length;
+		frag = New_fragment();
+		if(!frag){
+			fsck_err("%s: No space left\n",__func__);
+			goto free;
+		}
+		/*when clear chain or Trunc ,move this cluster cache to free tree for writefat()*/
+		frag->head = curr->head;
+		curr->length = curr->length;
+		insert = RB_INSERT(FSCK_MSDOS_FRAGMENT,&rb_free_root,frag);
+		if(insert)
+		fsck_warn("%s:fragment(head:0x%x) exist\n",__func__,frag->head);
+free:
 		free((void*)curr);
 	}
 	last->next = NULL;
@@ -313,18 +328,35 @@ int delete_fatcache_below(struct cluster_chain_descriptor * fatentry,struct fatc
  * cl -> the cluster whose below clusters will be removed
  *NOTE: this function was used to handle the issue when a file has incorrect cluster numbers
  */
-void Trunc(struct cluster_chain_descriptor *fat, unsigned int cl)
+void Trunc(struct bootblock *boot, struct cluster_chain_descriptor *fat, unsigned int cl)
 {
-	fsck_info("fat :%p ,cl : %d \n",fat,cl);
-	struct fatcache*prev ;
-	struct fatcache*cache =	Find_cache(fat,cl,&prev);
+	struct fatcache *prev , *cache = Find_cache(fat,cl,&prev);
+	unsigned int currlen = 0,org_chain_len = fat->length;
+	struct fragment *frag,*insert;
+	fsck_info("cluster chain :%p ,cl : %d \n",fat,cl);
+
 	if(!cache)
-		return ;
+		return;
 	delete_fatcache_below(fat,cache);
-	cache->length = cl - cache->head + 1;
-	fat->length -= (cache->length - (cl - cache->head) - 1);
+	currlen = cl - cache->head + 1;
+	if(currlen != cache->length){
+		frag = New_fragment();
+		if(!frag){
+			fsck_err("%s ,No space left\n",__func__);
+			goto re_calc;
+		}
+		frag->head = cl + 1;
+		frag->length = cache->length - currlen;
+		insert = RB_INSERT(FSCK_MSDOS_FRAGMENT,&rb_free_root,frag);
+		if(insert)
+		fsck_info("%s:fragment(head:0x%x) exist\n",__func__,frag->head);
+   }
+re_calc:
+	fat->length -= (cache->length - currlen);
+	cache->length = currlen;
+	/*re-calc Numfree*/
+	boot->NumFree += (org_chain_len - fat->length);
 }
-
 struct cluster_chain_descriptor* New_fatentry(void)
 {
 		struct cluster_chain_descriptor *fat;
diff --git a/fatcache.h b/fatcache.h
index ea8d5ff..db08af0 100644
--- a/fatcache.h
+++ b/fatcache.h
@@ -79,7 +79,7 @@ struct fatcache *Find_cache(struct cluster_chain_descriptor *fat,unsigned int cl
 /*find the next cluster*/
 struct fatcache	*Find_nextclus(struct cluster_chain_descriptor* fat,unsigned int clus, unsigned int* cl);
 int delete_fatcache_below(struct cluster_chain_descriptor* fatentry,struct fatcache*cache);
-void Trunc(struct cluster_chain_descriptor *fat, unsigned int cl);
+void Trunc(struct bootblock *boot, struct cluster_chain_descriptor *fat, unsigned int cl);
 void free_rb_tree(void);
 /*for test*/
 void Dump_fatentry(struct cluster_chain_descriptor *fat);