From 8de0788b9c7b2dce693b85801e9564576b9d9a21 Mon Sep 17 00:00:00 2001 From: Hallvard Furuseth Date: Tue, 27 Sep 2016 07:03:45 +0200 Subject: [PATCH] Only set me_mfd if needed. Drop unused read access. --- libraries/liblmdb/mdb.c | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-) diff --git a/libraries/liblmdb/mdb.c b/libraries/liblmdb/mdb.c index e2f1bbc..fe7f688 100644 --- a/libraries/liblmdb/mdb.c +++ b/libraries/liblmdb/mdb.c @@ -1239,7 +1239,7 @@ typedef struct MDB_pgstate { struct MDB_env { HANDLE me_fd; /**< The main data file */ HANDLE me_lfd; /**< The lock file */ - HANDLE me_mfd; /**< just for writing the meta pages */ + HANDLE me_mfd; /**< For writing and syncing the meta pages */ /** Failed to update the meta page. Probably an I/O error. */ #define MDB_FATAL_ERROR 0x80000000U /** Some fields are initialized. */ @@ -3827,7 +3827,10 @@ mdb_env_write_meta(MDB_txn *txn) len = sizeof(MDB_meta) - off; off += (char *)mp - env->me_map; - /* Write to the SYNC fd */ + /* Write to the SYNC fd unless MDB_NOSYNC/MDB_NOMETASYNC. + * (me_mfd goes to the same file as me_fd, but writing to it + * also syncs to disk. Avoids a separate fdatasync() call.) + */ mfd = (flags & (MDB_NOSYNC|MDB_NOMETASYNC)) ? env->me_fd : env->me_mfd; #ifdef _WIN32 { @@ -4156,7 +4159,7 @@ enum mdb_fopen_type { /* A comment in mdb_fopen() explains some O_* flag choices. */ MDB_O_RDONLY= O_RDONLY, /**< for RDONLY me_fd */ MDB_O_RDWR = O_RDWR |O_CREAT, /**< for me_fd */ - MDB_O_META = O_RDWR |MDB_DSYNC |MDB_CLOEXEC, /**< for me_mfd */ + MDB_O_META = O_WRONLY|MDB_DSYNC |MDB_CLOEXEC, /**< for me_mfd */ MDB_O_COPY = O_WRONLY|O_CREAT|O_EXCL|MDB_CLOEXEC, /**< for #mdb_env_copy() */ /** Bitmask for open() flags in enum #mdb_fopen_type. The other bits * distinguish otherwise-equal MDB_O_* constants from each other. @@ -4217,6 +4220,7 @@ mdb_fopen(const MDB_env *env, MDB_name *fname, disp = OPEN_EXISTING; break; case MDB_O_META: /* for writing metapages */ + acc = GENERIC_WRITE; disp = OPEN_EXISTING; attrs = FILE_ATTRIBUTE_NORMAL|FILE_FLAG_WRITE_THROUGH; break; @@ -4955,9 +4959,7 @@ mdb_env_open(MDB_env *env, const char *path, unsigned int flags, mdb_mode_t mode } if ((rc = mdb_env_open2(env)) == MDB_SUCCESS) { - if (flags & (MDB_RDONLY|MDB_WRITEMAP)) { - env->me_mfd = env->me_fd; - } else { + if (!(flags & (MDB_RDONLY|MDB_WRITEMAP))) { /* Synchronous fd for meta writes. Needed even with * MDB_NOSYNC/MDB_NOMETASYNC, in case these get reset. */ @@ -5040,7 +5042,7 @@ mdb_env_close0(MDB_env *env, int excl) if (env->me_map) { munmap(env->me_map, env->me_mapsize); } - if (env->me_mfd != env->me_fd && env->me_mfd != INVALID_HANDLE_VALUE) + if (env->me_mfd != INVALID_HANDLE_VALUE) (void) close(env->me_mfd); if (env->me_fd != INVALID_HANDLE_VALUE) (void) close(env->me_fd);