2010-12-14 19:00:04

by Eric Sandeen

[permalink] [raw]
Subject: [PATCH] e2fsprogs: fix type-punning warnings

Flags used during RHEL/Fedora builds lead to a couple type-punning
warnings:

recovery.c: In function 'do_one_pass':
recovery.c:539: warning: dereferencing type-punned pointer will break strict-aliasing rules
./csum.c: In function 'print_csum':
./csum.c:170: warning: dereferencing type-punned pointer will break strict-aliasing rules

The two changes below fix this up.

Note that the csum test binary output changes slightly, but this does
not break any tests.

Signed-off-by: Eric Sandeen <[email protected]>
---

diff --git a/e2fsck/recovery.c b/e2fsck/recovery.c
index 8e40575..cac9294 100644
--- a/e2fsck/recovery.c
+++ b/e2fsck/recovery.c
@@ -536,8 +536,10 @@ static int do_one_pass(journal_t *journal,
memcpy(nbh->b_data, obh->b_data,
journal->j_blocksize);
if (flags & JFS_FLAG_ESCAPE) {
- *((__be32 *)nbh->b_data) =
- cpu_to_be32(JFS_MAGIC_NUMBER);
+ journal_header_t *header;
+
+ header = (journal_header_t *) &nbh->b_data[0];
+ header->h_magic = cpu_to_be32(JFS_MAGIC_NUMBER);
}

BUFFER_TRACE(nbh, "marking dirty");
diff --git a/lib/ext2fs/Makefile.in b/lib/ext2fs/Makefile.in
index a71d12c..1024c10 100644
--- a/lib/ext2fs/Makefile.in
+++ b/lib/ext2fs/Makefile.in
@@ -317,7 +317,7 @@ tst_extents: $(srcdir)/extent.c extent_dbg.c $(DEBUG_OBJS) $(DEPLIBSS) \
tst_csum: csum.c $(STATIC_LIBEXT2FS) $(DEPLIBCOM_ERR)
$(E) " LD $@"
$(Q) $(CC) -o tst_csum $(srcdir)/csum.c -DDEBUG \
- $(ALL_CFLAGS) $(STATIC_LIBEXT2FS) $(LIBCOM_ERR)
+ $(ALL_CFLAGS) $(STATIC_LIBEXT2FS) $(LIBCOM_ERR) $(LIBE2P)

mkjournal: mkjournal.c $(STATIC_LIBEXT2FS) $(DEPLIBCOM_ERR)
$(E) " LD $@"
diff --git a/lib/ext2fs/csum.c b/lib/ext2fs/csum.c
index 58ebd23..2b6b364 100644
--- a/lib/ext2fs/csum.c
+++ b/lib/ext2fs/csum.c
@@ -166,9 +166,9 @@ void print_csum(const char *msg, ext2_filsys fs, dgrp_t group)
crc2 = ext2fs_crc16(crc1, &swabgroup, sizeof(swabgroup));
crc3 = ext2fs_crc16(crc2, desc,
offsetof(struct ext2_group_desc, bg_checksum));
- printf("%s: UUID %016Lx%016Lx(%04x), grp %u(%04x): %04x=%04x\n",
- msg, *(long long *)&sb->s_uuid, *(long long *)&sb->s_uuid[8],
- crc1, group, crc2, crc3, ext2fs_group_desc_csum(fs, group));
+ printf("%s: UUID %s(%04x), grp %u(%04x): %04x=%04x\n",
+ msg, e2p_uuid2str(sb->s_uuid), crc1, group, crc2,crc3,
+ ext2fs_group_desc_csum(fs, group));
}

unsigned char sb_uuid[16] = { 0x4f, 0x25, 0xe8, 0xcf, 0xe7, 0x97, 0x48, 0x23,


2010-12-15 18:54:31

by Edward Shishkin

[permalink] [raw]
Subject: Re: [PATCH] e2fsprogs: fix type-punning warnings

Eric Sandeen wrote:
> Flags used during RHEL/Fedora builds lead to a couple type-punning
> warnings:
>
> recovery.c: In function 'do_one_pass':
> recovery.c:539: warning: dereferencing type-punned pointer will break strict-aliasing rules
> ./csum.c: In function 'print_csum':
> ./csum.c:170: warning: dereferencing type-punned pointer will break strict-aliasing rules
>
> The two changes below fix this up.
>
> Note that the csum test binary output changes slightly, but this does
> not break any tests.
>
> Signed-off-by: Eric Sandeen <[email protected]>
>

Acked-by: Edward Shishkin <[email protected]>


> ---
>
> diff --git a/e2fsck/recovery.c b/e2fsck/recovery.c
> index 8e40575..cac9294 100644
> --- a/e2fsck/recovery.c
> +++ b/e2fsck/recovery.c
> @@ -536,8 +536,10 @@ static int do_one_pass(journal_t *journal,
> memcpy(nbh->b_data, obh->b_data,
> journal->j_blocksize);
> if (flags & JFS_FLAG_ESCAPE) {
> - *((__be32 *)nbh->b_data) =
> - cpu_to_be32(JFS_MAGIC_NUMBER);
> + journal_header_t *header;
> +
> + header = (journal_header_t *) &nbh->b_data[0];
> + header->h_magic = cpu_to_be32(JFS_MAGIC_NUMBER);
> }
>
> BUFFER_TRACE(nbh, "marking dirty");
> diff --git a/lib/ext2fs/Makefile.in b/lib/ext2fs/Makefile.in
> index a71d12c..1024c10 100644
> --- a/lib/ext2fs/Makefile.in
> +++ b/lib/ext2fs/Makefile.in
> @@ -317,7 +317,7 @@ tst_extents: $(srcdir)/extent.c extent_dbg.c $(DEBUG_OBJS) $(DEPLIBSS) \
> tst_csum: csum.c $(STATIC_LIBEXT2FS) $(DEPLIBCOM_ERR)
> $(E) " LD $@"
> $(Q) $(CC) -o tst_csum $(srcdir)/csum.c -DDEBUG \
> - $(ALL_CFLAGS) $(STATIC_LIBEXT2FS) $(LIBCOM_ERR)
> + $(ALL_CFLAGS) $(STATIC_LIBEXT2FS) $(LIBCOM_ERR) $(LIBE2P)
>
> mkjournal: mkjournal.c $(STATIC_LIBEXT2FS) $(DEPLIBCOM_ERR)
> $(E) " LD $@"
> diff --git a/lib/ext2fs/csum.c b/lib/ext2fs/csum.c
> index 58ebd23..2b6b364 100644
> --- a/lib/ext2fs/csum.c
> +++ b/lib/ext2fs/csum.c
> @@ -166,9 +166,9 @@ void print_csum(const char *msg, ext2_filsys fs, dgrp_t group)
> crc2 = ext2fs_crc16(crc1, &swabgroup, sizeof(swabgroup));
> crc3 = ext2fs_crc16(crc2, desc,
> offsetof(struct ext2_group_desc, bg_checksum));
> - printf("%s: UUID %016Lx%016Lx(%04x), grp %u(%04x): %04x=%04x\n",
> - msg, *(long long *)&sb->s_uuid, *(long long *)&sb->s_uuid[8],
> - crc1, group, crc2, crc3, ext2fs_group_desc_csum(fs, group));
> + printf("%s: UUID %s(%04x), grp %u(%04x): %04x=%04x\n",
> + msg, e2p_uuid2str(sb->s_uuid), crc1, group, crc2,crc3,
> + ext2fs_group_desc_csum(fs, group));
> }
>
> unsigned char sb_uuid[16] = { 0x4f, 0x25, 0xe8, 0xcf, 0xe7, 0x97, 0x48, 0x23,
> --
> To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
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>

2010-12-15 23:09:29

by Theodore Ts'o

[permalink] [raw]
Subject: Re: [PATCH] e2fsprogs: fix type-punning warnings

On Tue, Dec 14, 2010 at 01:00:01PM -0600, Eric Sandeen wrote:
> Flags used during RHEL/Fedora builds lead to a couple type-punning
> warnings:
>
> recovery.c: In function 'do_one_pass':
> recovery.c:539: warning: dereferencing type-punned pointer will break strict-aliasing rules
> ./csum.c: In function 'print_csum':
> ./csum.c:170: warning: dereferencing type-punned pointer will break strict-aliasing rules
>
> The two changes below fix this up.
>
> Note that the csum test binary output changes slightly, but this does
> not break any tests.
>
> Signed-off-by: Eric Sandeen <[email protected]>

Thanks, applied. There's also a bone-headed big-endian compile bug
which means I'll be doing an e2fsprogs 1.41.14 shortly.

- Ted

2010-12-16 20:39:41

by Eric Sandeen

[permalink] [raw]
Subject: Re: [PATCH] e2fsprogs: fix type-punning warnings

On 12/15/2010 05:09 PM, Ted Ts'o wrote:
> On Tue, Dec 14, 2010 at 01:00:01PM -0600, Eric Sandeen wrote:
>> Flags used during RHEL/Fedora builds lead to a couple type-punning
>> warnings:
>>
>> recovery.c: In function 'do_one_pass':
>> recovery.c:539: warning: dereferencing type-punned pointer will break strict-aliasing rules
>> ./csum.c: In function 'print_csum':
>> ./csum.c:170: warning: dereferencing type-punned pointer will break strict-aliasing rules
>>
>> The two changes below fix this up.
>>
>> Note that the csum test binary output changes slightly, but this does
>> not break any tests.
>>
>> Signed-off-by: Eric Sandeen <[email protected]>
>
> Thanks, applied. There's also a bone-headed big-endian compile bug
> which means I'll be doing an e2fsprogs 1.41.14 shortly.
>
> - Ted

Hm this may need an include of the e2p.h header as well, if built in
a pristine buildroot...

--- e2fsprogs-1.41.12.orig/lib/ext2fs/csum.c
+++ e2fsprogs-1.41.12/lib/ext2fs/csum.c
@@ -17,6 +17,7 @@
#include "ext2_fs.h"
#include "ext2fs.h"
#include "crc16.h"
+#include "e2p/e2p.h"
#include <assert.h>

#ifndef offsetof


Sorry about that,
-Eric

2010-12-16 22:15:11

by Theodore Ts'o

[permalink] [raw]
Subject: Re: [PATCH] e2fsprogs: fix type-punning warnings

On Thu, Dec 16, 2010 at 02:39:38PM -0600, Eric Sandeen wrote:
> Hm this may need an include of the e2p.h header as well, if built in
> a pristine buildroot...

Actually we only need it if we are building tst_csum (i.e., if #DEBUG
is defined). So I'll apply it under #ifdef DEBUG, and then add a
dependency for tst_csum in the Makefile.

Thanks for pointing this out.

- Ted