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authorDoug Zongker <dougz@android.com>2009-07-01 12:09:29 -0700
committerDoug Zongker <dougz@android.com>2009-07-01 12:09:29 -0700
commitbec02d57fb85cc7dd0196a54b0e9530e306623ac (patch)
tree88c0fc6a69cade6f9d4437666c6420e0f757e278
parentd8f7c9b85e25fab93fef2221a84b60edc2e7b837 (diff)
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skip over all-zero blocks when reading MTD partition
We fail to detect certain bad blocks (marked in the factory as bad, I think?) when reading mtd partitions. These come back as a block of all zeros. Since it's fairly unlikely a legitimate boot or recovery block will contain 128k of zeros, change mtdutils to skip over such blocks. Arve says https://review.source.android.com/10535 may be a long-term fix for this, but he isn't yet sure.
-rw-r--r--mtdutils/mtdutils.c13
1 files changed, 12 insertions, 1 deletions
diff --git a/mtdutils/mtdutils.c b/mtdutils/mtdutils.c
index 2b0106f..fc06766 100644
--- a/mtdutils/mtdutils.c
+++ b/mtdutils/mtdutils.c
@@ -297,7 +297,14 @@ static int read_block(const MtdPartition *partition, int fd, char *data)
after.corrected - before.corrected,
after.failed - before.failed, pos);
} else {
- return 0; // Success!
+ int i;
+ for (i = 0; i < size; ++i) {
+ if (data[i] != 0) {
+ return 0; // Success!
+ }
+ }
+ fprintf(stderr, "mtd: read all-zero block at 0x%08lx; skipping\n",
+ pos);
}
pos += partition->erase_size;
@@ -326,6 +333,10 @@ ssize_t mtd_read_data(MtdReadContext *ctx, char *data, size_t len)
read += ctx->partition->erase_size;
}
+ if (read >= len) {
+ return read;
+ }
+
// Read the next block into the buffer
if (ctx->consumed == ctx->partition->erase_size && read < (int) len) {
if (read_block(ctx->partition, ctx->fd, ctx->buffer)) return -1;