Author: obnox Date: 2007-07-20 14:23:12 +0000 (Fri, 20 Jul 2007) New Revision: 23977
WebSVN: http://websvn.samba.org/cgi-bin/viewcvs.cgi?view=rev&root=samba&rev=23977 Log: 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 Modified: branches/SAMBA_3_2/source/lib/tdb/common/io.c branches/SAMBA_3_2_0/source/lib/tdb/common/io.c branches/SAMBA_4_0/source/lib/tdb/common/io.c Changeset: Modified: branches/SAMBA_3_2/source/lib/tdb/common/io.c =================================================================== --- branches/SAMBA_3_2/source/lib/tdb/common/io.c 2007-07-19 14:49:08 UTC (rev 23976) +++ branches/SAMBA_3_2/source/lib/tdb/common/io.c 2007-07-20 14:23:12 UTC (rev 23977) @@ -232,15 +232,28 @@ 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; } Modified: branches/SAMBA_3_2_0/source/lib/tdb/common/io.c =================================================================== --- branches/SAMBA_3_2_0/source/lib/tdb/common/io.c 2007-07-19 14:49:08 UTC (rev 23976) +++ branches/SAMBA_3_2_0/source/lib/tdb/common/io.c 2007-07-20 14:23:12 UTC (rev 23977) @@ -232,15 +232,28 @@ 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; } Modified: branches/SAMBA_4_0/source/lib/tdb/common/io.c =================================================================== --- branches/SAMBA_4_0/source/lib/tdb/common/io.c 2007-07-19 14:49:08 UTC (rev 23976) +++ branches/SAMBA_4_0/source/lib/tdb/common/io.c 2007-07-20 14:23:12 UTC (rev 23977) @@ -232,15 +232,28 @@ 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; }
