Imported Upstream version 4.0.35

[platform/upstream/mtools.git] / file.c

diff --git a/file.c b/file.c
index d4b0667..d72c7d0 100644 (file)
--- a/file.c
+++ b/file.c
@@ -357,6 +357,9 @@ static int normal_map(File_t *This, uint32_t where, uint32_t *len, int mode,
        if(batchmode &&
           mode == MT_WRITE &&
           end >= This->FileSize) {
+               /* In batch mode, when writing at end of file, "pad"
+                * to nearest cluster boundary so that we don't have
+                * to read that data back from disk. */
                *len += ROUND_UP(end, clus_size) - end;
        }
 
@@ -441,13 +444,17 @@ static ssize_t write_file(Stream_t *Stream, char *buf,
                /* Error occured */
                return ret;
        if((uint32_t)ret > requestedLen)
+               /* More data than requested may be written to lower
+                * levels if batch mode is active, in order to "pad"
+                * the last cluster of a file, so that we don't have
+                * to read that back from disk */
                bytesWritten = requestedLen;
        else
-               bytesWritten = requestedLen;
+               bytesWritten = (uint32_t)ret;
        if (where + bytesWritten > This->FileSize )
                This->FileSize = where + bytesWritten;
        recalcPreallocSize(This);
-       return ret;
+       return (ssize_t)bytesWritten;
 }