diff options
Diffstat (limited to 'tools/virtiofsd/helper.c')
| -rw-r--r-- | tools/virtiofsd/helper.c | 47 |
1 files changed, 47 insertions, 0 deletions
diff --git a/tools/virtiofsd/helper.c b/tools/virtiofsd/helper.c index 819c2bc13c..00a1ef666a 100644 --- a/tools/virtiofsd/helper.c +++ b/tools/virtiofsd/helper.c @@ -23,6 +23,8 @@ #include <stdlib.h> #include <string.h> #include <sys/param.h> +#include <sys/time.h> +#include <sys/resource.h> #include <unistd.h> #define FUSE_HELPER_OPT(t, p) \ @@ -53,6 +55,7 @@ static const struct fuse_opt fuse_helper_opts[] = { FUSE_HELPER_OPT("subtype=", nodefault_subtype), FUSE_OPT_KEY("subtype=", FUSE_OPT_KEY_KEEP), FUSE_HELPER_OPT("max_idle_threads=%u", max_idle_threads), + FUSE_HELPER_OPT("--rlimit-nofile=%lu", rlimit_nofile), FUSE_HELPER_OPT("--syslog", syslog), FUSE_HELPER_OPT_VALUE("log_level=debug", log_level, FUSE_LOG_DEBUG), FUSE_HELPER_OPT_VALUE("log_level=info", log_level, FUSE_LOG_INFO), @@ -171,6 +174,10 @@ void fuse_cmdline_help(void) " default: no_writeback\n" " -o xattr|no_xattr enable/disable xattr\n" " default: no_xattr\n" + " --rlimit-nofile=<num> set maximum number of file descriptors\n" + " (0 leaves rlimit unchanged)\n" + " default: min(1000000, fs.file-max - 16384)\n" + " if the current rlimit is lower\n" ); } @@ -191,11 +198,51 @@ static int fuse_helper_opt_proc(void *data, const char *arg, int key, } } +static unsigned long get_default_rlimit_nofile(void) +{ + g_autofree gchar *file_max_str = NULL; + const rlim_t reserved_fds = 16384; /* leave at least this many fds free */ + rlim_t max_fds = 1000000; /* our default RLIMIT_NOFILE target */ + rlim_t file_max; + struct rlimit rlim; + + /* + * Reduce max_fds below the system-wide maximum, if necessary. This + * ensures there are fds available for other processes so we don't + * cause resource exhaustion. + */ + if (!g_file_get_contents("/proc/sys/fs/file-max", &file_max_str, + NULL, NULL)) { + fuse_log(FUSE_LOG_ERR, "can't read /proc/sys/fs/file-max\n"); + exit(1); + } + file_max = g_ascii_strtoull(file_max_str, NULL, 10); + if (file_max < 2 * reserved_fds) { + fuse_log(FUSE_LOG_ERR, + "The fs.file-max sysctl is too low (%lu) to allow a " + "reasonable number of open files.\n", + (unsigned long)file_max); + exit(1); + } + max_fds = MIN(file_max - reserved_fds, max_fds); + + if (getrlimit(RLIMIT_NOFILE, &rlim) < 0) { + fuse_log(FUSE_LOG_ERR, "getrlimit(RLIMIT_NOFILE): %m\n"); + exit(1); + } + + if (rlim.rlim_cur >= max_fds) { + return 0; /* we have more fds available than required! */ + } + return max_fds; +} + int fuse_parse_cmdline(struct fuse_args *args, struct fuse_cmdline_opts *opts) { memset(opts, 0, sizeof(struct fuse_cmdline_opts)); opts->max_idle_threads = 10; + opts->rlimit_nofile = get_default_rlimit_nofile(); opts->foreground = 1; if (fuse_opt_parse(args, opts, fuse_helper_opts, fuse_helper_opt_proc) == |