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storage/stream/flash: Failed write of reminder rewinds buffer offset

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The stream_flash_buffered_write, when invoked to do flush write, will
attempt to write the tail bytes from the buffer, filling the required
minimal write block size with erase value bytes; after write it rewinds
the buffer offset, bytes_written, by number of the "filler bytes".
Doe to lack of return code processing from flash_sync call, two things
would happen to context in case of failure:
 1) the ctx->bytes_written would be rewind pass the value it had before
    function call as it gets decremented by "filler bytes" even if write
    failed;
 2) the ctx->buf_bytes offset would be accounting for added "filler
    bytes" which should not be counted as data in buffer.

Proper processing of return code has been added to remove effects
described above.

Unit tests have been expended to cover the scenarios.

Signed-off-by: Dominik Ermel <dominik.ermel@nordicsemi.no>
This commit is contained in:
Dominik Ermel 2021-02-24 14:59:12 +00:00 • committed by Ioannis Glaropoulos
commit 32451230e2
2 changed files with 29 additions and 1 deletions
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6
subsys/storage/stream/stream_flash.c
View file

@ -161,7 +161,11 @@ int stream_flash_buffered_write(struct stream_flash_ctx *ctx, const uint8_t *dat
} }
rc = flash_sync(ctx); rc = flash_sync(ctx);
ctx->bytes_written -= fill_length; if (rc == 0) {
ctx->bytes_written -= fill_length;
} else {
ctx->buf_bytes -= fill_length;
}
} }
return rc; return rc;

24
tests/subsys/storage/stream/stream_flash/src/main.c
View file

@ -280,6 +280,11 @@ static int fake_write(const struct device *dev, off_t off, const void *data, siz
return 0; return 0;
} }
static int bad_write(const struct device *dev, off_t off, const void *data, size_t len)
{
return -EINVAL;
}
static void test_stream_flash_buffered_write_callback(void) static void test_stream_flash_buffered_write_callback(void)
{ {
int rc; int rc;
@ -338,6 +343,25 @@ static void test_stream_flash_buffered_write_callback(void)
zassert_equal(rc, -EINVAL, "expected failure from flash_sync", rc); zassert_equal(rc, -EINVAL, "expected failure from flash_sync", rc);
zassert_equal(ctx.buf_bytes, BUF_LEN, "Expected bytes to be left in buffer"); zassert_equal(ctx.buf_bytes, BUF_LEN, "Expected bytes to be left in buffer");
/* Pretend flashed context and attempt write write block - 1 bytes to trigger unaligned
* write; the write needs to fail so that we could check that context does not get modified.
*/
fake_api.write = bad_write;
bad_ctx.callback = NULL;
bad_ctx.buf_bytes = 0;
cmp_ctx = bad_ctx;
size_t wblock = flash_get_write_block_size(ctx.fdev);
size_t tow = (wblock == 1) ? 1 : wblock - 1;
rc = stream_flash_buffered_write(&bad_ctx, write_buf, tow, true);
zassert_equal(rc, -EINVAL, "expected failure from flash_sync", rc);
zassert_equal(cmp_ctx.bytes_written, bad_ctx.bytes_written,
"Expected bytes_written not modified");
/* The write failed but bytes have already been added to buffer and buffer offset
* increased.
*/
zassert_equal(bad_ctx.buf_bytes, cmp_ctx.buf_bytes + tow,
"Expected %d bytes added to buffer", tow);
} }
static void test_stream_flash_flush(void) static void test_stream_flash_flush(void)