From af8432e692eeb94bce80f155c6b9ab158258fff8 Mon Sep 17 00:00:00 2001 From: Michael Adam Date: Fri, 20 Jul 2007 14:23:12 +0000 Subject: r23977: Im prove the pwrite-patch to tdb_expand_file of r23972: * prevent infinite loops due to 0 bytes written: try once more. if we still get 0 as return, set errno to ENOSPC and return -1 (error) * replace int by correct types (ssize_t and size_t). * print a warning log message in case "written < requested to write" usually this means, that the next call to pwrite will fail with return value -1 and set errno accordingly. Note that the former error condition "written != requested to write" is not a correct error condition of write/pwrite. If this is due to an error, a subsequent call to (p)write will reveal the cause (typically "no space left on device" - ENOSPC). Michael (This used to be commit 7f415d12239fc67eb2c7894c6359b9507fe122c6) --- source4/lib/tdb/common/io.c | 27 ++++++++++++++++++++------- 1 file changed, 20 insertions(+), 7 deletions(-) diff --git a/source4/lib/tdb/common/io.c b/source4/lib/tdb/common/io.c index ea925f3895..a24b5e24a2 100644 --- a/source4/lib/tdb/common/io.c +++ b/source4/lib/tdb/common/io.c @@ -232,15 +232,28 @@ static int tdb_expand_file(struct tdb_context *tdb, tdb_off_t size, tdb_off_t ad disk. This must be done with write, not via mmap */ memset(buf, TDB_PAD_BYTE, sizeof(buf)); while (addition) { - int n = addition>sizeof(buf)?sizeof(buf):addition; - int ret = pwrite(tdb->fd, buf, n, size); - if (ret == -1) { - TDB_LOG((tdb, TDB_DEBUG_FATAL, "expand_file write of %d failed (%s)\n", - n, strerror(errno))); + size_t n = addition>sizeof(buf)?sizeof(buf):addition; + ssize_t written = pwrite(tdb->fd, buf, n, size); + if (written == 0) { + /* prevent infinite loops: try _once_ more */ + written = pwrite(tdb->fd, buf, n, size); + } + if (written == 0) { + /* give up, trying to provide a useful errno */ + TDB_LOG((tdb, TDB_DEBUG_FATAL, "expand_file write " + "returned 0 twice: giving up!\n")); + errno = ENOSPC; + return -1; + } else if (written == -1) { + TDB_LOG((tdb, TDB_DEBUG_FATAL, "expand_file write of " + "%d bytes failed (%s)\n", n, strerror(errno))); return -1; + } else if (written != n) { + TDB_LOG((tdb, TDB_DEBUG_WARNING, "expand_file: wrote " + "only %d of %d bytes - retrying\n", written,n)); } - addition -= ret; - size += ret; + addition -= written; + size += written; } return 0; } -- cgit