This is my replacement patch.
- Ted
commit 0a92af260da381e2581074871707e487728373ad
Author: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
Date: Fri Dec 12 18:27:12 2014 -0500
libext2fs: use a dynamically sized block zeroing buffer
Dynamically grow the block zeroing buffer to a maximum of 4MB, and
allow callers to provide their own zeroed buffer in
ext2fs_zero_blocks2().
Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
Signed-off-by: Theodore Ts'o <tytso@xxxxxxx>
diff --git a/lib/ext2fs/mkjournal.c b/lib/ext2fs/mkjournal.c
index e8f8b30..fcc6741 100644
--- a/lib/ext2fs/mkjournal.c
+++ b/lib/ext2fs/mkjournal.c
@@ -148,12 +148,13 @@ errfree:
* attempt to free the static zeroizing buffer. (This is to keep
* programs that check for memory leaks happy.)
*/
-#define STRIDE_LENGTH (4194304 / fs->blocksize)
+#define MAX_STRIDE_LENGTH (4194304 / (int) fs->blocksize)
errcode_t ext2fs_zero_blocks2(ext2_filsys fs, blk64_t blk, int num,
blk64_t *ret_blk, int *ret_count)
{
int j, count;
- static char *buf;
+ static void *buf;
+ static int stride_length;
errcode_t retval;
/* If fs is null, clean up the static buffer and return */
@@ -164,24 +165,36 @@ errcode_t ext2fs_zero_blocks2(ext2_filsys fs, blk64_t blk, int num,
}
return 0;
}
+
+ /* Deal with zeroing less than 1 block */
+ if (num <= 0)
+ return 0;
+
/* Allocate the zeroizing buffer if necessary */
- if (!buf) {
- buf = malloc(fs->blocksize * STRIDE_LENGTH);
- if (!buf)
- return ENOMEM;
- memset(buf, 0, fs->blocksize * STRIDE_LENGTH);
+ if (num > stride_length && stride_length < MAX_STRIDE_LENGTH) {
+ void *p;
+ int new_stride = num;
+
+ if (new_stride > MAX_STRIDE_LENGTH)
+ new_stride = MAX_STRIDE_LENGTH;
+ p = realloc(buf, fs->blocksize * new_stride);
+ if (!p)
+ return EXT2_ET_NO_MEMORY;
+ buf = p;
+ stride_length = new_stride;
+ memset(buf, 0, fs->blocksize * stride_length);
}
/* OK, do the write loop */
j=0;
while (j < num) {
- if (blk % STRIDE_LENGTH) {
- count = STRIDE_LENGTH - (blk % STRIDE_LENGTH);
+ if (blk % stride_length) {
+ count = stride_length - (blk % stride_length);
if (count > (num - j))
count = num - j;
} else {
count = num - j;
- if (count > STRIDE_LENGTH)
- count = STRIDE_LENGTH;
+ if (count > stride_length)
+ count = stride_length;
}
retval = io_channel_write_blk64(fs->io, blk, count, buf);
if (retval) {
--
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