b=21489 fix several write+utimes race conditions

Disable mtime updates on write and serialize fmd_mactime_xid checks in order to
avoid certain write(2)+utimes(2) race conditions on OSS

i=Johann Lombardi
i=Vitaly Fertman

diff --git a/lustre/include/obd_support.h b/lustre/include/obd_support.h
index 0d90654..c93a200 100644 (file)
--- a/lustre/include/obd_support.h
+++ b/lustre/include/obd_support.h
@@ -273,6 +273,7 @@ int obd_alloc_fail(const void *ptr, const char *name, const char *type,
 #define OBD_FAIL_OST_BRW_PAUSE_PACK      0x224
 #define OBD_FAIL_OST_CONNECT_NET2        0x225
 #define OBD_FAIL_OST_NOMEM               0x226
+#define OBD_FAIL_OST_BRW_PAUSE_BULK2     0x227
 
 #define OBD_FAIL_LDLM                    0x300
 #define OBD_FAIL_LDLM_NAMESPACE_NEW      0x301

diff --git a/lustre/obdfilter/filter.c b/lustre/obdfilter/filter.c
index 13c2530..711746a 100644 (file)
--- a/lustre/obdfilter/filter.c
+++ b/lustre/obdfilter/filter.c
@@ -3437,12 +3437,21 @@ int filter_setattr(struct obd_export *exp, struct obd_info *oinfo,
         filter = &exp->exp_obd->u.filter;
         push_ctxt(&saved, &exp->exp_obd->obd_lvfs_ctxt, NULL);
 
+        /*
+         * We need to be atomic against a concurrent write
+         * (which takes the semaphore for reading). fmd_mactime_xid
+         * checks will have no effect if a write request with lower
+         * xid starts just before a setattr and finishes later than
+         * the setattr (see bug 21489, comment 27).
+         */
         if (oa->o_valid &
             (OBD_MD_FLMTIME | OBD_MD_FLATIME | OBD_MD_FLCTIME)) {
+                down_write(&dentry->d_inode->i_alloc_sem);
                 fmd = filter_fmd_get(exp, oa->o_id, oa->o_gr);
                 if (fmd && fmd->fmd_mactime_xid < oti->oti_xid)
                         fmd->fmd_mactime_xid = oti->oti_xid;
                 filter_fmd_put(exp, fmd);
+                up_write(&dentry->d_inode->i_alloc_sem);
         }
 
         /* setting objects attributes (including owner/group) */

diff --git a/lustre/obdfilter/filter_io.c b/lustre/obdfilter/filter_io.c
index 7a2700f..3e7fee2 100644 (file)
--- a/lustre/obdfilter/filter_io.c
+++ b/lustre/obdfilter/filter_io.c
@@ -702,6 +702,14 @@ static int filter_preprw_write(int cmd, struct obd_export *exp, struct obdo *oa,
 
         fsfilt_check_slow(obd, now, "preprw_write setup");
 
+        /* Filter truncate first locks i_mutex then partially truncated
+         * page, filter write code first locks pages then take
+         * i_mutex.  To avoid a deadlock in case of concurrent
+         * punch/write requests from one client, filter writes and
+         * filter truncates are serialized by i_alloc_sem, allowing
+         * multiple writes or single truncate. */
+        down_read(&dentry->d_inode->i_alloc_sem);
+
         /* Don't update inode timestamps if this write is older than a
          * setattr which modifies the timestamps. b=10150 */
         /* XXX when we start having persistent reservations this needs to
@@ -737,18 +745,12 @@ static int filter_preprw_write(int cmd, struct obd_export *exp, struct obdo *oa,
         cfs_spin_unlock(&obd->obd_osfs_lock);
         filter_fmd_put(exp, fmd);
 
+        OBD_FAIL_TIMEOUT(OBD_FAIL_OST_BRW_PAUSE_BULK2, (obd_timeout + 1) / 4);
+
         if (rc)
                 GOTO(cleanup, rc);
         cleanup_phase = 4;
 
-        /* Filter truncate first locks i_mutex then partally truncated
-         * page, filter write code first locks pages then take
-         * i_mutex.  To avoid a deadlock in case of concurrent
-         * punch/write requests from one client, filter writes and
-         * filter truncates are serialized by i_alloc_sem, allowing
-         * multiple writes or single truncate. */
-        down_read(&dentry->d_inode->i_alloc_sem);
-
         cfs_gettimeofday(&start);
         for (i = 0, lnb = res; i < *npages; i++, lnb++) {
 
@@ -836,9 +838,11 @@ cleanup:
                                         lnb->page = NULL;
                                 }
                         }
-                        up_read(&dentry->d_inode->i_alloc_sem);
                 }
         case 3:
+                if (rc)
+                        up_read(&dentry->d_inode->i_alloc_sem);
+
                 filter_iobuf_put(&obd->u.filter, iobuf, oti);
         case 2:
                 pop_ctxt(&saved, &obd->obd_lvfs_ctxt, NULL);

diff --git a/lustre/ost/ost_handler.c b/lustre/ost/ost_handler.c
index 9c20008..28f3deb 100644 (file)
--- a/lustre/ost/ost_handler.c
+++ b/lustre/ost/ost_handler.c
@@ -1129,6 +1129,13 @@ static int ost_brw_write(struct ptlrpc_request *req, struct obd_trans_info *oti)
                 repbody->oa.o_gid = o_gid;
         }
 
+        /*
+         * Disable sending mtime back to the client. If the client locked the
+         * whole object, then it has already updated the mtime on its side,
+         * otherwise it will have to glimpse anyway (see bug 21489, comment 32)
+         */
+        repbody->oa.o_valid &= ~(OBD_MD_FLMTIME | OBD_MD_FLATIME);
+
         if (unlikely(client_cksum != server_cksum && rc == 0)) {
                 int  new_cksum = ost_checksum_bulk(desc, OST_WRITE, cksum_type);
                 char *msg;

diff --git a/lustre/tests/sanity.sh b/lustre/tests/sanity.sh
index be74422..7541e1e 100644 (file)
--- a/lustre/tests/sanity.sh
+++ b/lustre/tests/sanity.sh
@@ -74,7 +74,7 @@ init_test_env $@
 . ${CONFIG:=$LUSTRE/tests/cfg/${NAME}.sh}
 init_logging
 
-[ "$SLOW" = "no" ] && EXCEPT_SLOW="24o 24v 27m 36f 36g 51b 51c 60c 63 64b 68 71 73 77f 78 101 103 115 120g 124b"
+[ "$SLOW" = "no" ] && EXCEPT_SLOW="24o 24v 27m 36f 36g 36h 51b 51c 60c 63 64b 68 71 73 77f 78 101 103 115 120g 124b"
 
 SANITYLOG=${TESTSUITELOG:-$TMP/$(basename $0 .sh).log}
 FAIL_ON_ERROR=false
@@ -1830,15 +1830,15 @@ test_36e() {
 }
 run_test 36e "utime on non-owned file (should return error) ===="
 
-test_36f() {
+subr_36fh() {
+       local fl="$1"
        local LANG_SAVE=$LANG
        local LC_LANG_SAVE=$LC_LANG
        export LANG=C LC_LANG=C # for date language
 
        DATESTR="Dec 20  2000"
        mkdir -p $DIR/$tdir
-       #define OBD_FAIL_OST_BRW_PAUSE_BULK 0x214
-       lctl set_param fail_loc=0x80000214
+       lctl set_param fail_loc=$fl
        date; date +%s
        cp /etc/hosts $DIR/$tdir/$tfile
        sync & # write RPC generated with "current" inode timestamp, but delayed
@@ -1856,6 +1856,11 @@ test_36f() {
 
        export LANG=$LANG_SAVE LC_LANG=$LC_LANG_SAVE
 }
+
+test_36f() {
+       #define OBD_FAIL_OST_BRW_PAUSE_BULK 0x214
+       subr_36fh "0x80000214"
+}
 run_test 36f "utime on file racing with OST BRW write =========="
 
 test_36g() {
@@ -1873,6 +1878,12 @@ test_36g() {
 }
 run_test 36g "filter mod data cache expiry ====================="
 
+test_36h() {
+       #define OBD_FAIL_OST_BRW_PAUSE_BULK2 0x227
+       subr_36fh "0x80000227"
+}
+run_test 36h "utime on file racing with OST BRW write =========="
+
 test_37() {
        mkdir -p $DIR/$tdir
        echo f > $DIR/$tdir/fbugfile