On 10/19/2011 01:28 PM, J. Bruce Fields wrote: > On Wed, Oct 19, 2011 at 01:10:19PM -0400, Steve Dickson wrote: >> >> >> On 10/19/2011 12:36 PM, Jeff Layton wrote: >>> On Wed, 19 Oct 2011 11:34:30 -0400 >>> Steve Dickson <steved@xxxxxxxxxx> wrote: >>> >>>> This patch is a following on to commit 7a802337. Using the >>>> tool in https://bugzilla.redhat.com/show_bug.cgi?id=695916 >>>> caused the fflush() and fclose() to fail in turn causing >>>> corruption in the mtab. >>>> >>>> The failures were in the internals of both calls. Switch those >>>> calls with the actual system calls eliminated the failures. >>>> >>>> Signed-off-by: Steve Dickson <steved@xxxxxxxxxx> >>>> --- >>>> support/nfs/nfs_mntent.c | 4 ++-- >>>> 1 files changed, 2 insertions(+), 2 deletions(-) >>>> >>>> diff --git a/support/nfs/nfs_mntent.c b/support/nfs/nfs_mntent.c >>>> index a2118a2..b80f270 100644 >>>> --- a/support/nfs/nfs_mntent.c >>>> +++ b/support/nfs/nfs_mntent.c >>>> @@ -117,7 +117,7 @@ void >>>> nfs_endmntent (mntFILE *mfp) { >>>> if (mfp) { >>>> if (mfp->mntent_fp) >>>> - fclose(mfp->mntent_fp); >>>> + close(fileno(mfp->mntent_fp)); >>>> if (mfp->mntent_file) >>>> free(mfp->mntent_file); >>>> free(mfp); >>>> @@ -147,7 +147,7 @@ nfs_addmntent (mntFILE *mfp, struct mntent *mnt) { >>>> free(m3); >>>> free(m4); >>>> if (res >= 0) { >>>> - res = fflush(mfp->mntent_fp); >>>> + res = fsync(fileno(mfp->mntent_fp)); >>> >>> fsync doesn't imply an fflush. With this, I think you may end up >>> without everything being committed to disk if part or all of it is >>> still in the file stream buffer. You probably want to do an fflush() >>> and then an fsync here. >> The problem was with the fflush() call. The call was causing the >> mount to drop core in turn causing mtab corruption. Changing that >> call to a fsync() worked just fine... no corruption... every time! > > Looking at man setrlimit.... If you're worried about RLIMIT_FSIZE, then > I guess you need to handle SIGXFSZ and EFBIG returns from write(). > > It looks like lock_mtab() already sets SIGXFSZ to be ignored. Is a libc > bug crashing fflush on EFBIG? Or maybe the ftruncate is a problem? > Maybe you just want to do away with stream IO completely? Calling fsync() clearly works. So why are looking for alternative solutions?? steved. -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
