fs/fat: Remove two statements without effect

fatlength is a local variable which is no more used after the assignment. s_name is not used in the function, save the strncpy.

Signed-off-by Stefan Br?ns <[email protected]>

---
 fs/fat/fat_write.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

fs/fat/fat_write.c +0 -1

index eb3a916..961ccd8 100644
@@ -183,7 +183,6 @@ static __u32 get_fatent_value(fsdata *mydata,
 __u32 entry) if (getsize > fatlength)
 			getsize = fatlength;
 
-		fatlength *= mydata->sect_size;	/* We want it

in bytes now */ startblock += mydata->fat_sect; /* Offset from
start of disk */

fs/fat/fat_write.c +0 -0

 		/* Write back the fatbuf to the disk */

@@ -326,10 +325,8 @@ fill_dir_slot(fsdata *mydata, dir_entry
 **dentptr, const char *l_name) dir_slot *slotptr = (dir_slot

fatlength is a local variable which is no more used after the assignment. s_name is not used in the function, save the strncpy.

fatlength is a local variable which is no more used after the assignment. s_name is not used in the function, save the strncpy.

Signed-off-by Stefan Br?ns <[email protected]>

fatlength is a local variable which is no more used after the assignment. s_name is not used in the function, save the strncpy.

Signed-off-by Stefan Br?ns <[email protected]>

Acked-by Lukasz Majewski <[email protected]>

Acked-by Stephen Warren <[email protected]>

Reviewed-by Beno?t Th?baudeau <[email protected]>

The code caches 6 sectors of the FAT. On FAT traversal, the old contents needs to be flushed to disk, but only if any FAT entries had been modified. Explicitly flag the buffer on modification.

Currently, creating a new file traverses the whole FAT up to the first free cluster and rewrites the on-disk blocks.

Signed-off-by Stefan Br?ns <[email protected]>

---
 fs/fat/fat.c       |  1 +
 fs/fat/fat_write.c | 31 +++++++++++++++++++------------
 include/fat.h      |  1 +
 3 files changed, 21 insertions(+), 12 deletions(-)

fs/fat/fat.c +1 -0

index 826bd85..df9f2b5 100644
@@ -876,6 +876,7 @@ int do_fat_read_at(const char *filename, loff_t
 pos, void *buffer, }
 
 	mydata->fatbufnum = -1;
+	mydata->fat_dirty = 0;
 	mydata->fatbuf = memalign(ARCH_DMA_MINALIGN, FATBUFSIZE);
 	if (mydata->fatbuf == NULL) {
 		debug("Error: allocating memory\n");

fs/fat/fat_write.c +8 -1

index 961ccd8..babe9c8 100644
@@ -104,13 +104,19 @@ static __u8 num_of_fats;
 /*
  * Write fat buffer into block device
  */
-static int flush_fat_buffer(fsdata *mydata)
+static int flush_dirty_fat_buffer(fsdata *mydata)
 {
 	int getsize = FATBUFBLOCKS;
 	__u32 fatlength = mydata->fatlength;
 	__u8 *bufptr = mydata->fatbuf;
 	__u32 startblock = mydata->fatbufnum * FATBUFBLOCKS;
 
+	debug("debug: evicting %d, dirty: %d\n", mydata->fatbufnum,
+	      (int)mydata->fat_dirty);
+
+	if ((!mydata->fat_dirty) || (mydata->fatbufnum == -1))
+		return 0;
+
 	startblock += mydata->fat_sect;
 
 	if (getsize > fatlength)

@@ -130,6 +136,7 @@ static int flush_fat_buffer(fsdata *mydata)
 			return -1;
 		}
 	}
+	mydata->fat_dirty = 0;
 
 	return 0;
 }

@@ -186,10 +193,8 @@ static __u32 get_fatent_value(fsdata *mydata,

__u32 entry) startblock += mydata->fat_sect; /* Offset from
start of disk */

fs/fat/fat_write.c +11 -11

 		/* Write back the fatbuf to the disk */
-		if (mydata->fatbufnum != -1) {
-			if (flush_fat_buffer(mydata) < 0)
-				return -1;
-		}
+		if (flush_dirty_fat_buffer(mydata) < 0)
+			return -1;
 
 		if (disk_read(startblock, getsize, bufptr) < 0) {
 			debug("Error reading FAT blocks\n");

@@ -494,10 +499,8 @@ static int set_fatent_value(fsdata *mydata,
 __u32 entry, __u32 entry_value) if (getsize > fatlength)
 			getsize = fatlength;
 
-		if (mydata->fatbufnum != -1) {
-			if (flush_fat_buffer(mydata) < 0)
-				return -1;
-		}
+		if (flush_dirty_fat_buffer(mydata) < 0)
+			return -1;
 
 		if (disk_read(startblock, getsize, bufptr) < 0) {
 			debug("Error reading FAT blocks\n");

@@ -506,6 +509,9 @@ static int set_fatent_value(fsdata *mydata, __u32
 entry, __u32 entry_value) mydata->fatbufnum = bufnum;
 	}
 
+	/* Mark as dirty */
+	mydata->fat_dirty = 1;
+
 	/* Set the actual entry */
 	switch (mydata->fatsize) {
 	case 32:

@@ -645,7 +651,7 @@ static void flush_dir_table(fsdata *mydata,
 dir_entry **dentptr) 
 	dir_curclust = dir_newclust;
 
-	if (flush_fat_buffer(mydata) < 0)
+	if (flush_dirty_fat_buffer(mydata) < 0)
 		return;
 
 	memset(get_dentfromdir_block, 0x00,

@@ -675,7 +681,7 @@ static int clear_fatent(fsdata *mydata, __u32
 entry) }
 
 	/* Flush fat buffer */
-	if (flush_fat_buffer(mydata) < 0)
+	if (flush_dirty_fat_buffer(mydata) < 0)
 		return -1;
 
 	return 0;

@@ -1011,6 +1017,7 @@ static int do_fat_write(const char *filename,
 void *buffer, loff_t size, }
 
 	mydata->fatbufnum = -1;
+	mydata->fat_dirty = 0;
 	mydata->fatbuf = memalign(ARCH_DMA_MINALIGN, FATBUFSIZE);
 	if (mydata->fatbuf == NULL) {
 		debug("Error: allocating memory\n");

@@ -1111,7 +1118,7 @@ static int do_fat_write(const char *filename,
 void *buffer, loff_t size, debug("attempt to write 0x%llx bytes\n",
 *actwrite); 
 	/* Flush fat buffer */
-	ret = flush_fat_buffer(mydata);
+	ret = flush_dirty_fat_buffer(mydata);
 	if (ret) {
 		printf("Error: flush fat buffer\n");
 		goto exit;

include/fat.h +1 -0

index 9d053e6..8ec91cd 100644
@@ -169,6 +169,7 @@ typedef struct {
 	int	fatsize;	/* Size of FAT in bits */
 	__u32	fatlength;	/* Length of FAT in sectors */
 	__u16	fat_sect;	/* Starting sector of the FAT
 */
+	__u8	fat_dirty;      /* Set if fatbuf has been

modified */ __u32 rootdir_sect; /* Start sector of root
directory */ __u16 sect_size; /* Size of sectors in
bytes */ __u16 clust_size; /* Size of clusters in
sectors */

The code caches 6 sectors of the FAT. On FAT traversal, the old contents needs to be flushed to disk, but only if any FAT entries had been modified. Explicitly flag the buffer on modification.

Currently, creating a new file traverses the whole FAT up to the first free cluster and rewrites the on-disk blocks.

Signed-off-by Stefan Br?ns <[email protected]>

Reviewed-by Lukasz Majewski <[email protected]>

Current description does not match the function behaviour.

Signed-off-by Stefan Br?ns <[email protected]>

---
 fs/fat/fat_write.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

fs/fat/fat_write.c +1 -1

index babe9c8..0583af3 100644
@@ -528,7 +528,8 @@ static int set_fatent_value(fsdata *mydata, __u32
 entry, __u32 entry_value) }
 
 /*
- * Determine the entry value at index 'entry' in a FAT (16/32) table
+ * Determine the next free cluster after 'entry' in a FAT (16/32)

table
+ * and link it to 'entry'. EOC marker is not set on returned entry. */
static __u32 determine_fatent(fsdata *mydata, __u32 entry) {

Current description does not match the function behaviour.

Signed-off-by Stefan Br?ns <[email protected]>

Acked-by Lukasz Majewski <[email protected]>

argc is checked, but is off by one. In case <bytes> is not specified, create an empty file, which is identical to the ext4write behaviour.

Signed-off-by Stefan Br?ns <[email protected]>

---
 cmd/fat.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

argc is checked, but is off by one. In case <bytes> is not specified, create an empty file, which is identical to the ext4write behaviour.

Signed-off-by Stefan Br?ns <[email protected]>

Reviewed-by Simon Glass <[email protected]>