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From: prajnoha@sourceware.org To: lvm-devel@redhat.com, lvm2-cvs@sourceware.org Subject: LVM2 ./WHATS_NEW lib/format_text/archive.c Date: Thu, 09 Sep 2010 13:13:00 -0000 [thread overview] Message-ID: <20100909131314.13747.qmail@sourceware.org> (raw) CVSROOT: /cvs/lvm2 Module name: LVM2 Changes by: prajnoha@sourceware.org 2010-09-09 13:13:12 Modified files: . : WHATS_NEW lib/format_text: archive.c Log message: Add random suffix to archive file names to prevent races when being created. In certain configurations, we're not under a VG rw lock while trying to write a new archive file with VG metadata. A common example is using "vgs" while having the content of backup and archive directories empty. The code scans the content of these directories and tries to determine the final index that should be used in archive name. Since we're not under a lock, we can get into a race while choosing the index which could end up showing errors about not being able to rename to final archive name. Let's add random number suffix to these archive file names so we can avoid the race. Patches: http://sourceware.org/cgi-bin/cvsweb.cgi/LVM2/WHATS_NEW.diff?cvsroot=lvm2&r1=1.1728&r2=1.1729 http://sourceware.org/cgi-bin/cvsweb.cgi/LVM2/lib/format_text/archive.c.diff?cvsroot=lvm2&r1=1.38&r2=1.39 --- LVM2/WHATS_NEW 2010/09/09 13:07:13 1.1728 +++ LVM2/WHATS_NEW 2010/09/09 13:13:12 1.1729 @@ -1,5 +1,6 @@ Version 2.02.74 - ================================== + Add random suffix to archive file names to prevent races when being created. Reinitialize archive and backup handling on toolcontext refresh. Fix opprobriously slow I/O to cluster mirrors created with --nosync. Make poll_mirror_progress report PROGRESS_CHECK_FAILED if LV is not a mirror. --- LVM2/lib/format_text/archive.c 2010/08/03 13:09:22 1.38 +++ LVM2/lib/format_text/archive.c 2010/09/09 13:13:12 1.39 @@ -226,7 +226,7 @@ const char *dir, const char *desc, uint32_t retain_days, uint32_t min_archive) { - int i, fd, renamed = 0; + int i, fd, rnum, renamed = 0; uint32_t ix = 0; struct archive_file *last; FILE *fp = NULL; @@ -271,9 +271,12 @@ ix = last->index + 1; } + rnum = rand_r(&vg->cmd->rand_seed); + for (i = 0; i < 10; i++) { if (dm_snprintf(archive_name, sizeof(archive_name), - "%s/%s_%05u.vg", dir, vg->name, ix) < 0) { + "%s/%s_%05u-%d.vg", + dir, vg->name, ix, rnum) < 0) { log_error("Archive file name too long."); return 0; }
next reply other threads:[~2010-09-09 13:13 UTC|newest] Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top 2010-09-09 13:13 prajnoha [this message] -- strict thread matches above, loose matches on Subject: below -- 2010-08-03 13:09 zkabelac 2006-03-07 15:43 agk
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