| Message ID | 20180222183445.GG9827@magnolia (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Thu, Feb 22, 2018 at 10:34:45AM -0800, Darrick J. Wong wrote: > On Thu, Feb 22, 2018 at 06:17:31PM +0000, Luis Henriques wrote: > > On Thu, Feb 22, 2018 at 09:27:41AM -0800, Darrick J. Wong wrote: > > > On Thu, Feb 22, 2018 at 04:06:14PM +0000, Luis Henriques wrote: > > > > On Thu, Dec 14, 2017 at 06:07:31PM -0800, Darrick J. Wong wrote: > > > > > > > > <snip> > > > > > > > > > +void > > > > > +clonerange_f( > > > > > + int opno, > > > > > + long r) > > > > > +{ > > > > > > > > <snip> > > > > > > > > > + /* Calculate offsets */ > > > > > + len = (random() % FILELEN_MAX) + 1; > > > > > + len &= ~(stat1.st_blksize - 1); > > > > > + if (len == 0) > > > > > + len = stat1.st_blksize; > > > > > + if (len > stat1.st_size) > > > > > + len = stat1.st_size; > > > > > + > > > > > + lr = ((__int64_t)random() << 32) + random(); > > > > > + if (stat1.st_size == len) > > > > > + off1 = 0; > > > > > + else > > > > > + off1 = (off64_t)(lr % MIN(stat1.st_size - len, MAXFSIZE)); > > > > > + off1 %= maxfsize; > > > > > + off1 &= ~(stat1.st_blksize - 1); > > > > > + > > > > > + /* > > > > > + * If srcfile == destfile, randomly generate destination ranges > > > > > + * until we find one that doesn't overlap the source range. > > > > > + */ > > > > > + do { > > > > > + lr = ((__int64_t)random() << 32) + random(); > > > > > + off2 = (off64_t)(lr % MIN(stat2.st_size + (1024 * 1024), MAXFSIZE)); > > > > > + off2 %= maxfsize; > > > > > + off2 &= ~(stat2.st_blksize - 1); > > > > > + } while (stat1.st_ino == stat2.st_ino && llabs(off2 - off1) < len); > > > > > > > > I started seeing hangs in generic/013 on cephfs. After spending some > > > > time looking, I found that this loops forever. And the reason seems to > > > > be that stat1.st_blksize is too big for this filesystem (4M) -- when > > > > doing: > > > > > > "Too big for this filesystem"? > > > > > > Uh... maybe you'd better start by giving me more stat buffer info -- > > > what's st_size? > > > > > > > off1 &= ~(stat1.st_blksize - 1); > > > > > > These bits round the start offset down to block granularity, since clone > > > range implementations generally require that the ranges align to block > > > boundaries. > > > > > > (Though AFAICT ceph doesn't support clone range anyway...) > > > > > > So reading between the lines, is the problem here that ceph advertises a > > > blocksize of 4M and fsstress calls clonerange_f with files that are > > > smaller than 4M in size, so the only possible offsets with a 4M > > > blocksize are zero and that's why we end up looping forever? > > > > Brilliantly described! That is *exactly* what I'm seeing and failed to > > describe. I guess I could use FSSTRESS_AVOID to work around this issue, > > but there are probably better options. > > Better to patch fsstress.c against this bug. :) > > Does the following patch help? Yes, it does. Thanks! Feel free to add my Tested-by: Luis Henriques <lhenriques@suse.com> Cheers, -- Luís > > --D > > diff --git a/ltp/fsstress.c b/ltp/fsstress.c > index 935f5de..e107099 100644 > --- a/ltp/fsstress.c > +++ b/ltp/fsstress.c > @@ -2222,6 +2222,7 @@ clonerange_f( > off64_t lr; > off64_t off1; > off64_t off2; > + off64_t max_off2; > size_t len; > int v1; > int v2; > @@ -2305,9 +2306,10 @@ clonerange_f( > * If srcfile == destfile, randomly generate destination ranges > * until we find one that doesn't overlap the source range. > */ > + max_off2 = MIN(stat2.st_size + (1024ULL * stat2.st_blksize), MAXFSIZE); > do { > lr = ((int64_t)random() << 32) + random(); > - off2 = (off64_t)(lr % MIN(stat2.st_size + (1024 * 1024), MAXFSIZE)); > + off2 = (off64_t)(lr % max_off2); > off2 %= maxfsize; > off2 &= ~(stat2.st_blksize - 1); > } while (stat1.st_ino == stat2.st_ino && llabs(off2 - off1) < len); > -- To unsubscribe from this list: send the line "unsubscribe fstests" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/ltp/fsstress.c b/ltp/fsstress.c index 935f5de..e107099 100644 --- a/ltp/fsstress.c +++ b/ltp/fsstress.c @@ -2222,6 +2222,7 @@ clonerange_f( off64_t lr; off64_t off1; off64_t off2; + off64_t max_off2; size_t len; int v1; int v2; @@ -2305,9 +2306,10 @@ clonerange_f( * If srcfile == destfile, randomly generate destination ranges * until we find one that doesn't overlap the source range. */ + max_off2 = MIN(stat2.st_size + (1024ULL * stat2.st_blksize), MAXFSIZE); do { lr = ((int64_t)random() << 32) + random(); - off2 = (off64_t)(lr % MIN(stat2.st_size + (1024 * 1024), MAXFSIZE)); + off2 = (off64_t)(lr % max_off2); off2 %= maxfsize; off2 &= ~(stat2.st_blksize - 1); } while (stat1.st_ino == stat2.st_ino && llabs(off2 - off1) < len);