From bdd29249a882e599e5e365536372d08dee398cd4 Mon Sep 17 00:00:00 2001

From: Harald Hoyer <harald@redhat.com>

Date: Fri, 19 Apr 2013 13:44:56 +0200

Subject: [PATCH] Reintroduce f_type comparison macro

This reverts commit 4826f0b7b5c0aefa08b8cc7ef64d69027f84da2c.

Because statfs.t_type can be int on some architecures, we have to cast

the const magic to the type, otherwise the compiler warns about

signed/unsigned comparison, because the magic can be 32 bit unsigned.

statfs(2) man page is also wrong on some systems, because

f_type is not __SWORD_TYPE on some architecures.

The following program:

int main(int argc, char**argv)

{

        struct statfs s;

        statfs(argv[1], &s);

	printf("sizeof(f_type) = %d\n", sizeof(s.f_type));

	printf("sizeof(__SWORD_TYPE) = %d\n", sizeof(__SWORD_TYPE));

	printf("sizeof(long) = %d\n", sizeof(long));

	printf("sizeof(int) = %d\n", sizeof(int));

	if (sizeof(s.f_type) == sizeof(int)) {

		printf("f_type = 0x%x\n", s.f_type);

	} else {

                printf("f_type = 0x%lx\n", s.f_type);

	}

        return 0;

}

executed on s390x gives for a btrfs:

sizeof(f_type) = 4

sizeof(__SWORD_TYPE) = 8

sizeof(long) = 8

sizeof(int) = 4

f_type = 0x9123683e

---

 src/journal/sd-journal.c          | 10 +++++-----

 src/readahead/readahead-collect.c |  2 +-

 src/shared/macro.h                |  7 +++++++

 src/shared/util.c                 |  5 +++--

 4 files changed, 16 insertions(+), 8 deletions(-)

diff --git a/src/journal/sd-journal.c b/src/journal/sd-journal.c

index e021d98..15239b5 100644

--- a/src/journal/sd-journal.c

+++ b/src/journal/sd-journal.c

@@ -1251,11 +1251,11 @@ static void check_network(sd_journal *j, int fd) {

                 return;

         j->on_network =

-                sfs.f_type == (__SWORD_TYPE) CIFS_MAGIC_NUMBER ||

-                sfs.f_type == (__SWORD_TYPE) CODA_SUPER_MAGIC ||

-                sfs.f_type == (__SWORD_TYPE) NCP_SUPER_MAGIC ||

-                sfs.f_type == (__SWORD_TYPE) NFS_SUPER_MAGIC ||

-                sfs.f_type == (__SWORD_TYPE) SMB_SUPER_MAGIC;

+                F_TYPE_CMP(sfs.f_type, CIFS_MAGIC_NUMBER) ||

+                F_TYPE_CMP(sfs.f_type, CODA_SUPER_MAGIC) ||

+                F_TYPE_CMP(sfs.f_type, NCP_SUPER_MAGIC) ||

+                F_TYPE_CMP(sfs.f_type, NFS_SUPER_MAGIC) ||

+                F_TYPE_CMP(sfs.f_type, SMB_SUPER_MAGIC);

 }

 static int add_file(sd_journal *j, const char *prefix, const char *filename) {

diff --git a/src/readahead/readahead-collect.c b/src/readahead/readahead-collect.c

index 02ecbe5..75ec5b7 100644

--- a/src/readahead/readahead-collect.c

+++ b/src/readahead/readahead-collect.c

@@ -505,7 +505,7 @@ done:

         on_ssd = fs_on_ssd(root) > 0;

         log_debug("On SSD: %s", yes_no(on_ssd));

-        on_btrfs = statfs(root, &sfs) >= 0 && sfs.f_type == (__SWORD_TYPE) BTRFS_SUPER_MAGIC;

+        on_btrfs = statfs(root, &sfs) >= 0 && F_TYPE_CMP(sfs.f_type, BTRFS_SUPER_MAGIC);

         log_debug("On btrfs: %s", yes_no(on_btrfs));

         if (asprintf(&pack_fn_new, "%s/.readahead.new", root) < 0) {

diff --git a/src/shared/macro.h b/src/shared/macro.h

index 9bf81dc..ac61b49 100644

--- a/src/shared/macro.h

+++ b/src/shared/macro.h

@@ -264,6 +264,13 @@ do {                                                                    \

         }                                                               \

 } while(false)

+ /* Because statfs.t_type can be int on some architecures, we have to cast

+  * the const magic to the type, otherwise the compiler warns about

+  * signed/unsigned comparison, because the magic can be 32 bit unsigned.

+ */

+#define F_TYPE_CMP(a, b) (a == (typeof(a)) b)

+

+

 /* Returns the number of chars needed to format variables of the

  * specified type as a decimal string. Adds in extra space for a

  * negative '-' prefix. */

diff --git a/src/shared/util.c b/src/shared/util.c

index 5d03272..1fc6c5a 100644

--- a/src/shared/util.c

+++ b/src/shared/util.c

@@ -2779,8 +2779,9 @@ int rm_rf_children_dangerous(int fd, bool only_dirs, bool honour_sticky, struct

 static int is_temporary_fs(struct statfs *s) {

         assert(s);

-        return s->f_type == (__SWORD_TYPE) TMPFS_MAGIC ||

-                s->f_type == (__SWORD_TYPE) RAMFS_MAGIC;

+        return

+                F_TYPE_CMP(s->f_type, TMPFS_MAGIC) ||

+                F_TYPE_CMP(s->f_type, RAMFS_MAGIC);

 }

 int rm_rf_children(int fd, bool only_dirs, bool honour_sticky, struct stat *root_dev) {

-- 

1.8.2