Modified ext2 code to use GetN/PutN.

lsvmutils/ext2.c

@@ -140,6 +140,59 @@ static void _HexDump(
 typedef unsigned long ssize_t;
 #endif
 
+static ssize_t _ReadPartialBlock(
+    Blkdev* dev,
+    UINTN blkno,
+    size_t offset,
+    size_t size,
+    void* data)
+{
+    UINT8 blk[BLKDEV_BLKSIZE];
+    UINT32 off; /* offset into this block */
+    UINT32 len; /* bytes to read from this block */
+
+    if (!size)
+        return 0;
+
+    if (dev->GetN(dev, blkno, 1, blk) != 0)
+        return -1;
+
+    off = offset % BLKDEV_BLKSIZE;
+    len = _Min(BLKDEV_BLKSIZE - off, size);
+    Memcpy(data, &blk[off], len);
+    return len;
+}
+
+static ssize_t _WritePartialBlock(
+   Blkdev* dev,
+   UINTN blkno,
+   ssize_t offset,
+   size_t size,
+   const void* data)
+{
+    UINT8 blk[BLKDEV_BLKSIZE];
+    UINT32 off; /* offset into this block */
+    UINT32 len; /* bytes to read from this block */
+
+    if (!size)
+        return 0;
+
+    /* Fetch the block */
+    if (dev->GetN(dev, blkno, 1, blk) != 0)
+        return -1;
+
+    /* Replace the specified data in the block. */
+    off = offset % BLKDEV_BLKSIZE;
+    len = _Min(BLKDEV_BLKSIZE - off, size);
+    Memcpy(&blk[off], data, len);
+
+    /* Rewrite the block */
+    if (dev->PutN(dev, blkno, 1, blk) != 0)
+        return -1;
+
+    return len;
+}
+
 static ssize_t _Read(
     Blkdev* dev,
     size_t offset,
@@ -147,40 +200,44 @@ static ssize_t _Read(
     size_t size)
 {
     UINT32 blkno;
-    UINT32 i;
+    UINT32 nblocks;
     UINT32 rem;
     UINT8* ptr;
+    ssize_t bytesRead;
 
     if (!dev || !data)
         return -1;
 
     blkno = offset / BLKDEV_BLKSIZE;
+    rem = size;
+    ptr = data;
 
-    for (i = blkno, rem = size, ptr = (UINT8*)data; rem; i++)
+    /* Handle the special case if offset is unaligned to the sector. */
+    if (offset % BLKDEV_BLKSIZE != 0)
     {
-        UINT8 blk[BLKDEV_BLKSIZE];
-        UINT32 off; /* offset into this block */
-        UINT32 len; /* bytes to read from this block */
-
-        if (dev->Get(dev, i, blk) != 0)
+        bytesRead = _ReadPartialBlock(dev, blkno, offset, rem, ptr);
+        if (bytesRead < 0)
             return -1;
 
-        /* If first block */
-        if (i == blkno)
-            off = offset % BLKDEV_BLKSIZE;
-        else
-            off = 0;
-
-        len = BLKDEV_BLKSIZE - off;
-
-        if (len > rem)
-            len = rem;
-
-        Memcpy(ptr, &blk[off], len);
-        rem -= len;
-        ptr += len;
+        blkno++;
+        rem -= bytesRead;
+        ptr += bytesRead;
     }
 
+    /* Read the remaining full blocks. */
+    nblocks = rem / BLKDEV_BLKSIZE;
+    if (dev->GetN(dev, blkno, nblocks, ptr) != 0)
+        return -1;
+
+    blkno += nblocks;
+    rem -= nblocks * BLKDEV_BLKSIZE;
+    ptr += nblocks * BLKDEV_BLKSIZE;
+
+    /* Read the last partial block if needed. */
+    bytesRead = _ReadPartialBlock(dev, blkno, 0, rem, ptr);
+    if (bytesRead < 0)
+        return -1;
+
     return size;
 }
 
@@ -191,45 +248,44 @@ static ssize_t _Write(
     size_t size)
 {
     UINT32 blkno;
-    UINT32 i;
+    UINT32 nblocks;
     UINT32 rem;
-    UINT8* ptr;
+    const UINT8* ptr;
+    ssize_t bytesWritten;
 
     if (!dev || !data)
         return -1;
 
     blkno = offset / BLKDEV_BLKSIZE;
+    rem = size;
+    ptr = data;
 
-    for (i = blkno, rem = size, ptr = (UINT8*)data; rem; i++)
+    /* Handle the special case if offset is not aligned to sector. */
+    if (offset % BLKDEV_BLKSIZE != 0)
     {
-        UINT8 blk[BLKDEV_BLKSIZE];
-        UINT32 off; /* offset into this block */
-        UINT32 len; /* bytes to write from this block */
-
-        /* Fetch the block */
-        if (dev->Get(dev, i, blk) != 0)
+        bytesWritten = _WritePartialBlock(dev, blkno, offset, rem, ptr);
+        if (bytesWritten < 0)
             return -1;
 
-        /* If first block */
-        if (i == blkno)
-            off = offset % BLKDEV_BLKSIZE;
-        else
-            off = 0;
-
-        len = BLKDEV_BLKSIZE - off;
-
-        if (len > rem)
-            len = rem;
-
-        Memcpy(&blk[off], ptr, len);
-        rem -= len;
-        ptr += len;
-
-        /* Rewrite the block */
-        if (dev->Put(dev, i, blk) != 0)
-            return -1;
+        blkno++;
+        rem -= bytesWritten;
+        ptr += bytesWritten;
     }
 
+    /* Write the remaining blocks full blocks. */
+    nblocks = rem / BLKDEV_BLKSIZE;
+    if (dev->PutN(dev, blkno, nblocks, ptr) != 0)
+        return -1;
+
+    blkno += nblocks;
+    rem -= nblocks * BLKDEV_BLKSIZE;
+    ptr += nblocks * BLKDEV_BLKSIZE;
+
+    /* Write the partial block if needed. */
+    bytesWritten = _WritePartialBlock(dev, blkno, 0, rem, ptr);
+    if (bytesWritten < 0)
+        return -1;
+
     return size;
 }
 
@@ -3774,7 +3830,7 @@ EXT2Err EXT2Rm(
     /* Truncate the file first */
     if (EXT2_IFERR(err = EXT2Trunc(ext2, path)))
     {
-        goto done;
+        GOTO(done);
     }
 
     /* Split the path */