On Mon, 2021-03-15 at 15:53 +0100, David Sterba wrote: > On Sun, Mar 14, 2021 at 07:49:13PM +0100, Pierre Labastie wrote: > > After sending the first version of the patch, I realized that it > > was flawed, because of some formatting by the MUA. It took me > > some time to set up an MTA so that git send-email works. Now the > > patch should apply cleanly. Please remove the present paragraph by using > > git am -c. Apologies for the inconvenience(s). > > -- >8 -- > > Commit b3df561fbf has introduced the ability to convert extended > > inode time precision on ext4, but this breaks builds on older distros, > > where ext4 does not have the nsec time precision. > > > > Commit c615287cc tried to fix that by testing the availability of > > the EXT4_EPOCH_MASK macro, but the test is not complete. > > > > This patch aims at fixing the macro test, and changes the > > name of the associated HAVE_ macro, since the logic is reverted. > > > > This fixes #353 when ext4 has nsec time precision. Note that > > the test fails when ext4 does not have the nsec time precision. > > Maybe the test shouldn't be run in that case? > > > > Issue: #353 > > Signed-off-by: Pierre Labastie <pierre.labas...@neuf.fr> > > --- > > configure.ac | 8 ++++---- > > convert/source-ext2.c | 6 +++--- > > 2 files changed, 7 insertions(+), 7 deletions(-) > > > > diff --git a/configure.ac b/configure.ac > > index 612a3f87..dd6a5de7 100644 > > --- a/configure.ac > > +++ b/configure.ac > > @@ -251,10 +251,10 @@ else > > AC_DEFINE([HAVE_OWN_FIEMAP_EXTENT_SHARED_DEFINE], [0], [We did not define > > FIEMAP_EXTENT_SHARED]) > > fi > > > > -HAVE_OWN_EXT4_EPOCH_MASK_DEFINE=0 > > -AX_CHECK_DEFINE([ext2fs/ext2_fs.h], [EXT4_EPOCH_MASK], [], > > - [HAVE_OWN_EXT4_EPOCH_MASK_DEFINE=1 > > - AC_MSG_WARN([no definition of EXT4_EPOCH_MASK found, > > probably old e2fsprogs, will use own definition, no 64bit time precision of > > converted images])]) > > +AX_CHECK_DEFINE([ext2fs/ext2_fs.h], [EXT4_EPOCH_MASK], > > + [AC_DEFINE([HAVE_EXT4_EPOCH_MASK_DEFINE], [1], > > + [Define to 1 if e2fsprogs defines EXT4_EPOCH_MASK])], > > + [AC_MSG_WARN([no definition of EXT4_EPOCH_MASK found, > > probably old e2fsprogs, will use own definition, no 64bit time precision of > > converted images])]) > > Inlining the AC_DEFINE to the check will skip defining the macro in case > the EXT4_EPOCH_MASK does not exist and then the C #if won't work. > > HAVE_EXT4_EPOCH_MASK_DEFINE=0 > AX_CHECK_DEFINE(... > HAVE_EXT4_EPOCH_MASK_DEFINE=1,...) > > if x"$HAVE_EXT4_EPOCH_MASK_DEFINE"; then > AC_DEFINE([HAVE_EXT4_EPOCH_MASK_DEFINE], [1]) > else > AC_DEFINE([HAVE_EXT4_EPOCH_MASK_DEFINE], [0]) > fi
Since autoheader is used, and autoheader uses AC_DEFINE macros to generate config.h.in, there is a risk that having two AC_DEFINE macros for the same identifier generates a conflict. I've not been able to find what it does in that case in the autoconf doc. OTOH, an undefined identifier is replaced by a zero when expanding a #if in the C preprocessor (this is in all the norms I have access to: C89 and C99), that is: #if UNDEFINED_IDENTIFIER is equivalent to #if 0 Except if a compiler does not respect the norm, what I have proposed works (I have only tested with gcc, and it does what it is supposed to do). > > This should work, maybe it's not the shortest way to write that but I > can't find anything better. Now, I've tested your version, and it works too. So, up to you... Pierre
