From 462dc097451834477b597447af69c5acc93182b7 Mon Sep 17 00:00:00 2001 From: Howard Chu Date: Thu, 8 Jan 2015 12:54:14 +0000 Subject: [PATCH] fdatasync hack, again Check for ext3/ext4 fs, then check kernel version. --- libraries/liblmdb/mdb.c | 62 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 62 insertions(+) diff --git a/libraries/liblmdb/mdb.c b/libraries/liblmdb/mdb.c index cc6eaa2..b6703d6 100644 --- a/libraries/liblmdb/mdb.c +++ b/libraries/liblmdb/mdb.c @@ -1180,6 +1180,9 @@ struct MDB_env { #ifdef _WIN32 int me_pidquery; /**< Used in OpenProcess */ #endif +#ifdef __linux + int me_fsynconly; /**< fdatasync is unreliable */ +#endif #if defined(_WIN32) || defined(MDB_USE_SYSV_SEM) /* Windows mutexes/SysV semaphores do not reside in shared mem */ mdb_mutex_t me_rmutex; @@ -2356,6 +2359,12 @@ mdb_env_sync(MDB_env *env, int force) rc = ErrCode(); #endif } else { +#ifdef __linux + if (env->me_fsynconly) { + if (fsync(env->me_fd)) + rc = ErrCode(); + } else +#endif if (MDB_FDATASYNC(env->me_fd)) rc = ErrCode(); } @@ -3918,6 +3927,11 @@ mdb_fsize(HANDLE fd, size_t *size) return MDB_SUCCESS; } +#ifdef __linux +#include +#include +#endif + /** Further setup required for opening an LMDB environment */ static int ESECT @@ -3936,6 +3950,54 @@ mdb_env_open2(MDB_env *env) env->me_pidquery = PROCESS_QUERY_INFORMATION; #endif /* _WIN32 */ +#ifdef __linux + /* ext3/ext4 fdatasync is broken on some older Linux kernels. + * https://lkml.org/lkml/2012/9/3/83 + * Kernels after 3.6-rc6 are known good. + * https://lkml.org/lkml/2012/9/10/556 + * See if the DB is on ext3/ext4, then check for new enough kernel + * Kernels 2.6.32.60, 2.6.34.15, 3.2.30, and 3.5.4 are also known + * to be patched. + */ + { + struct statfs st; + fstatfs(env->me_fd, &st); + while (st.f_type == 0xEF53) { + struct utsname uts; + int i; + uname(&uts); + if (uts.release[0] < '3') { + if (!strncmp(uts.release, "2.6.32.", 7)) { + i = atoi(uts.release+7); + if (i >= 60) + break; /* 2.6.32.60 and newer is OK */ + } else if (!strncmp(uts.release, "2.6.34.", 7)) { + i = atoi(uts.release+7); + if (i >= 15) + break; /* 2.6.34.15 and newer is OK */ + } + } else if (uts.release[0] == '3') { + i = atoi(uts.release+2); + if (i > 5) + break; /* 3.6 and newer is OK */ + if (i == 5) { + i = atoi(uts.release+4); + if (i >= 4) + break; /* 3.5.4 and newer is OK */ + } else if (i == 2) { + i = atoi(uts.release+4); + if (i >= 30) + break; /* 3.2.30 and newer is OK */ + } + } else { /* 4.x and newer is OK */ + break; + } + env->me_fsynconly = 1; + break; + } + } +#endif + if ((i = mdb_env_read_header(env, &meta)) != 0) { if (i != ENOENT) return i; -- 2.7.4