From 3dd4200569133042cbf914f8158b703a9bb9a9a7 Mon Sep 17 00:00:00 2001 From: Thomas Munro Date: Mon, 25 Sep 2017 22:22:48 +0100 Subject: [PATCH] Fix error handling for posix_fallocate(). Commit 899bd785c0edf376077d3f5d65c316f92c1b64b5 introduced the use of posix_fallocate() to pre-allocate tmpfs space, based on an earlier proposal that used fallocate(). It assumed that posix_fallocate() set errno like fallocate(), but in fact it doesn't. So fix that. Also remove the handling for ENOSYS which is not a documented return value for posix_fallocate(), and shouldn't happen because posix_fallocate() is supposed to provide a fallback strategy if the underlying fallocate syscall is not available. Author: Thomas Munro Discussion: https://postgr.es/m/CAEepm%3D2Z%2BUrtAApqOaBbzko8oxcb8NBmx%2B2JnLnWGRVbzZAsXQ%40mail.gmail.com --- src/backend/storage/ipc/dsm_impl.c | 17 +++++++---------- 1 file changed, 7 insertions(+), 10 deletions(-) diff --git a/src/backend/storage/ipc/dsm_impl.c b/src/backend/storage/ipc/dsm_impl.c index a587906..e1b4143 100644 --- a/src/backend/storage/ipc/dsm_impl.c +++ b/src/backend/storage/ipc/dsm_impl.c @@ -425,17 +425,14 @@ dsm_impl_posix_resize(int fd, off_t size) do { rc = posix_fallocate(fd, 0, size); - } while (rc == -1 && errno == EINTR); + } while (rc == EINTR); - if (rc != 0 && errno == ENOSYS) - { - /* - * Kernel too old (< 2.6.23). Rather than fail, just trust that - * we won't hit the problem (it typically doesn't show up without - * many-GB-sized requests, anyway). - */ - rc = 0; - } + /* + * The caller expects errno to be set, but posix_fallocate() doesn't + * set it. Instead it returns error numbers directly. So set errno, + * even though we'll also return rc to indicate success or failure. + */ + errno = rc; } #endif /* HAVE_POSIX_FALLOCATE && __linux__ */ -- 1.8.3.1