lustre/llite: simplify dentry revalidate
authorLai Siyao <lai.siyao@intel.com>
Sat, 1 Mar 2014 02:16:38 +0000 (21:16 -0500)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Sat, 1 Mar 2014 03:11:20 +0000 (19:11 -0800)
Lustre client dentry validation is protected by LDLM lock, so
any time a dentry is found, it's valid and no need to revalidate
from MDS, and even it does, there is race that it may be
invalidated after revalidation is finished.

Signed-off-by: Lai Siyao <lai.siyao@intel.com>
Reviewed-on: http://review.whamcloud.com/7475
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-3544
Reviewed-by: Peng Tao <bergwolf@gmail.com>
Reviewed-by: Bob Glossman <bob.glossman@intel.com>
Reviewed-by: John L. Hammond <john.hammond@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>
Signed-off-by: Oleg Drokin <oleg.drokin@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/staging/lustre/lustre/include/lustre/lustre_idl.h
drivers/staging/lustre/lustre/llite/dcache.c
drivers/staging/lustre/lustre/llite/file.c
drivers/staging/lustre/lustre/llite/llite_internal.h
drivers/staging/lustre/lustre/lmv/lmv_intent.c
drivers/staging/lustre/lustre/lmv/lmv_obd.c
drivers/staging/lustre/lustre/mdc/mdc_locks.c

index a55eebfda165abebb6530e688bc285910a617e4e..5f5b0ba9ea94afefbd9ac13edf7b623900f548c2 100644 (file)
@@ -2112,7 +2112,7 @@ extern void lustre_swab_generic_32s (__u32 *val);
 #define DISP_LOOKUP_POS      0x00000008
 #define DISP_OPEN_CREATE     0x00000010
 #define DISP_OPEN_OPEN       0x00000020
-#define DISP_ENQ_COMPLETE    0x00400000
+#define DISP_ENQ_COMPLETE    0x00400000                /* obsolete and unused */
 #define DISP_ENQ_OPEN_REF    0x00800000
 #define DISP_ENQ_CREATE_REF  0x01000000
 #define DISP_OPEN_LOCK       0x02000000
index 3907c87c2ba1b03cc257d0bd03392df6dfc8ef9d..f971a543cb586afa69f4ad9aa9ff15b071267bd1 100644 (file)
@@ -241,9 +241,6 @@ void ll_intent_release(struct lookup_intent *it)
                 ptlrpc_req_finished(it->d.lustre.it_data); /* ll_file_open */
        if (it_disposition(it, DISP_ENQ_CREATE_REF)) /* create rec */
                ptlrpc_req_finished(it->d.lustre.it_data);
-       if (it_disposition(it, DISP_ENQ_COMPLETE)) /* saved req from revalidate
-                                                   * to lookup */
-               ptlrpc_req_finished(it->d.lustre.it_data);
 
        it->d.lustre.it_disposition = 0;
        it->d.lustre.it_data = NULL;
@@ -328,262 +325,32 @@ void ll_frob_intent(struct lookup_intent **itp, struct lookup_intent *deft)
 
 }
 
-int ll_revalidate_it(struct dentry *de, int lookup_flags,
-                    struct lookup_intent *it)
+static int ll_revalidate_dentry(struct dentry *dentry,
+                               unsigned int lookup_flags)
 {
-       struct md_op_data *op_data;
-       struct ptlrpc_request *req = NULL;
-       struct lookup_intent lookup_it = { .it_op = IT_LOOKUP };
-       struct obd_export *exp;
-       struct inode *parent = de->d_parent->d_inode;
-       int rc;
-
-       CDEBUG(D_VFSTRACE, "VFS Op:name=%s,intent=%s\n", de->d_name.name,
-              LL_IT2STR(it));
-
-       LASSERT(de != de->d_sb->s_root);
-
-       if (de->d_inode == NULL) {
-               __u64 ibits;
-
-               /* We can only use negative dentries if this is stat or lookup,
-                  for opens and stuff we do need to query server. */
-               /* If there is IT_CREAT in intent op set, then we must throw
-                  away this negative dentry and actually do the request to
-                  kernel to create whatever needs to be created (if possible)*/
-               if (it && (it->it_op & IT_CREAT))
-                       return 0;
+       struct inode *dir = dentry->d_parent->d_inode;
 
-               if (d_lustre_invalid(de))
-                       return 0;
-
-               ibits = MDS_INODELOCK_UPDATE;
-               rc = ll_have_md_lock(parent, &ibits, LCK_MINMODE);
-               GOTO(out_sa, rc);
-       }
-
-       /* Never execute intents for mount points.
-        * Attributes will be fixed up in ll_inode_revalidate_it */
-       if (d_mountpoint(de))
-               GOTO(out_sa, rc = 1);
-
-       exp = ll_i2mdexp(de->d_inode);
-
-       OBD_FAIL_TIMEOUT(OBD_FAIL_MDC_REVALIDATE_PAUSE, 5);
-       ll_frob_intent(&it, &lookup_it);
-       LASSERT(it);
+       /*
+        * if open&create is set, talk to MDS to make sure file is created if
+        * necessary, because we can't do this in ->open() later since that's
+        * called on an inode. return 0 here to let lookup to handle this.
+        */
+       if ((lookup_flags & (LOOKUP_OPEN | LOOKUP_CREATE)) ==
+           (LOOKUP_OPEN | LOOKUP_CREATE))
+               return 0;
 
-       if (it->it_op == IT_LOOKUP && !d_lustre_invalid(de))
+       if (lookup_flags & (LOOKUP_PARENT | LOOKUP_OPEN | LOOKUP_CREATE))
                return 1;
 
-       if (it->it_op == IT_OPEN) {
-               struct inode *inode = de->d_inode;
-               struct ll_inode_info *lli = ll_i2info(inode);
-               struct obd_client_handle **och_p;
-               __u64 ibits;
-
-               /*
-                * We used to check for MDS_INODELOCK_OPEN here, but in fact
-                * just having LOOKUP lock is enough to justify inode is the
-                * same. And if inode is the same and we have suitable
-                * openhandle, then there is no point in doing another OPEN RPC
-                * just to throw away newly received openhandle.  There are no
-                * security implications too, if file owner or access mode is
-                * change, LOOKUP lock is revoked.
-                */
-
-
-               if (it->it_flags & FMODE_WRITE)
-                       och_p = &lli->lli_mds_write_och;
-               else if (it->it_flags & FMODE_EXEC)
-                       och_p = &lli->lli_mds_exec_och;
-               else
-                       och_p = &lli->lli_mds_read_och;
-
-               /* Check for the proper lock. */
-               ibits = MDS_INODELOCK_LOOKUP;
-               if (!ll_have_md_lock(inode, &ibits, LCK_MINMODE))
-                       goto do_lock;
-               mutex_lock(&lli->lli_och_mutex);
-               if (*och_p) { /* Everything is open already, do nothing */
-                       /* Originally it was idea to do not let them steal our
-                        * open handle from under us by (*och_usecount)++ here.
-                        * But in case we have the handle, but we cannot use it
-                        * due to later checks (e.g. O_CREAT|O_EXCL flags set),
-                        * nobody would decrement counter increased here. So we
-                        * just hope the lock won't be invalidated in between.
-                        * But if it would be, we'll reopen the open request to
-                        * MDS later during file open path.
-                        */
-                       mutex_unlock(&lli->lli_och_mutex);
-                       return 1;
-               }
-               mutex_unlock(&lli->lli_och_mutex);
-       }
-
-       if (it->it_op == IT_GETATTR) {
-               rc = ll_statahead_enter(parent, &de, 0);
-               if (rc == 1)
-                       goto mark;
-               else if (rc != -EAGAIN && rc != 0)
-                       GOTO(out, rc = 0);
-       }
-
-do_lock:
-       op_data = ll_prep_md_op_data(NULL, parent, de->d_inode,
-                                    de->d_name.name, de->d_name.len,
-                                    0, LUSTRE_OPC_ANY, NULL);
-       if (IS_ERR(op_data))
-               return PTR_ERR(op_data);
-
-       if (!IS_POSIXACL(parent) || !exp_connect_umask(exp))
-               it->it_create_mode &= ~current_umask();
-       it->it_create_mode |= M_CHECK_STALE;
-       rc = md_intent_lock(exp, op_data, NULL, 0, it,
-                           lookup_flags,
-                           &req, ll_md_blocking_ast, 0);
-       it->it_create_mode &= ~M_CHECK_STALE;
-       ll_finish_md_op_data(op_data);
-
-       /* If req is NULL, then md_intent_lock only tried to do a lock match;
-        * if all was well, it will return 1 if it found locks, 0 otherwise. */
-       if (req == NULL && rc >= 0) {
-               if (!rc)
-                       goto do_lookup;
-               GOTO(out, rc);
-       }
-
-       if (rc < 0) {
-               if (rc != -ESTALE) {
-                       CDEBUG(D_INFO, "ll_intent_lock: rc %d : it->it_status "
-                              "%d\n", rc, it->d.lustre.it_status);
-               }
-               GOTO(out, rc = 0);
-       }
-
-revalidate_finish:
-       rc = ll_revalidate_it_finish(req, it, de);
-       if (rc != 0) {
-               if (rc != -ESTALE && rc != -ENOENT)
-                       ll_intent_release(it);
-               GOTO(out, rc = 0);
-       }
-
-       if ((it->it_op & IT_OPEN) && de->d_inode &&
-           !S_ISREG(de->d_inode->i_mode) &&
-           !S_ISDIR(de->d_inode->i_mode)) {
-               ll_release_openhandle(de, it);
-       }
-       rc = 1;
-
-out:
-       /* We do not free request as it may be reused during following lookup
-        * (see comment in mdc/mdc_locks.c::mdc_intent_lock()), request will
-        * be freed in ll_lookup_it or in ll_intent_release. But if
-        * request was not completed, we need to free it. (bug 5154, 9903) */
-       if (req != NULL && !it_disposition(it, DISP_ENQ_COMPLETE))
-               ptlrpc_req_finished(req);
-       if (rc == 0) {
-               /* mdt may grant layout lock for the newly created file, so
-                * release the lock to avoid leaking */
-               ll_intent_drop_lock(it);
-               ll_invalidate_aliases(de->d_inode);
-       } else {
-               __u64 bits = 0;
-               __u64 matched_bits = 0;
-
-               CDEBUG(D_DENTRY, "revalidated dentry %.*s (%p) parent %p "
-                      "inode %p refc %d\n", de->d_name.len,
-                      de->d_name.name, de, de->d_parent, de->d_inode,
-                      d_count(de));
-
-               ll_set_lock_data(exp, de->d_inode, it, &bits);
-
-               /* Note: We have to match both LOOKUP and PERM lock
-                * here to make sure the dentry is valid and no one
-                * changing the permission.
-                * But if the client connects < 2.4 server, which will
-                * only grant LOOKUP lock, so we can only Match LOOKUP
-                * lock for old server */
-               if (exp_connect_flags(ll_i2mdexp(de->d_inode)) &&
-                                                       OBD_CONNECT_LVB_TYPE)
-                       matched_bits =
-                               MDS_INODELOCK_LOOKUP | MDS_INODELOCK_PERM;
-               else
-                       matched_bits = MDS_INODELOCK_LOOKUP;
-
-               if (((bits & matched_bits) == matched_bits) &&
-                   d_lustre_invalid(de))
-                       d_lustre_revalidate(de);
-               ll_lookup_finish_locks(it, de);
-       }
-
-mark:
-       if (it != NULL && it->it_op == IT_GETATTR && rc > 0)
-               ll_statahead_mark(parent, de);
-       return rc;
+       if (d_need_statahead(dir, dentry) <= 0)
+               return 1;
 
-       /*
-        * This part is here to combat evil-evil race in real_lookup on 2.6
-        * kernels.  The race details are: We enter do_lookup() looking for some
-        * name, there is nothing in dcache for this name yet and d_lookup()
-        * returns NULL.  We proceed to real_lookup(), and while we do this,
-        * another process does open on the same file we looking up (most simple
-        * reproducer), open succeeds and the dentry is added. Now back to
-        * us. In real_lookup() we do d_lookup() again and suddenly find the
-        * dentry, so we call d_revalidate on it, but there is no lock, so
-        * without this code we would return 0, but unpatched real_lookup just
-        * returns -ENOENT in such a case instead of retrying the lookup. Once
-        * this is dealt with in real_lookup(), all of this ugly mess can go and
-        * we can just check locks in ->d_revalidate without doing any RPCs
-        * ever.
-        */
-do_lookup:
-       if (it != &lookup_it) {
-               /* MDS_INODELOCK_UPDATE needed for IT_GETATTR case. */
-               if (it->it_op == IT_GETATTR)
-                       lookup_it.it_op = IT_GETATTR;
-               ll_lookup_finish_locks(it, de);
-               it = &lookup_it;
-       }
+       if (lookup_flags & LOOKUP_RCU)
+               return -ECHILD;
 
-       /* Do real lookup here. */
-       op_data = ll_prep_md_op_data(NULL, parent, NULL, de->d_name.name,
-                                    de->d_name.len, 0, (it->it_op & IT_CREAT ?
-                                                        LUSTRE_OPC_CREATE :
-                                                        LUSTRE_OPC_ANY), NULL);
-       if (IS_ERR(op_data))
-               return PTR_ERR(op_data);
-
-       rc = md_intent_lock(exp, op_data, NULL, 0,  it, 0, &req,
-                           ll_md_blocking_ast, 0);
-       if (rc >= 0) {
-               struct mdt_body *mdt_body;
-               struct lu_fid fid = {.f_seq = 0, .f_oid = 0, .f_ver = 0};
-               mdt_body = req_capsule_server_get(&req->rq_pill, &RMF_MDT_BODY);
-
-               if (de->d_inode)
-                       fid = *ll_inode2fid(de->d_inode);
-
-               /* see if we got same inode, if not - return error */
-               if (lu_fid_eq(&fid, &mdt_body->fid1)) {
-                       ll_finish_md_op_data(op_data);
-                       op_data = NULL;
-                       goto revalidate_finish;
-               }
-               ll_intent_release(it);
-       }
-       ll_finish_md_op_data(op_data);
-       GOTO(out, rc = 0);
-
-out_sa:
-       /*
-        * For rc == 1 case, should not return directly to prevent losing
-        * statahead windows; for rc == 0 case, the "lookup" will be done later.
-        */
-       if (it != NULL && it->it_op == IT_GETATTR && rc == 1)
-               ll_statahead_enter(parent, &de, 1);
-       goto mark;
+       do_statahead_enter(dir, &dentry, dentry->d_inode == NULL);
+       ll_statahead_mark(dir, dentry);
+       return 1;
 }
 
 /*
@@ -591,24 +358,13 @@ out_sa:
  */
 int ll_revalidate_nd(struct dentry *dentry, unsigned int flags)
 {
-       struct inode *parent = dentry->d_parent->d_inode;
-       int unplug = 0;
+       int rc;
 
-       CDEBUG(D_VFSTRACE, "VFS Op:name=%s,flags=%u\n",
+       CDEBUG(D_VFSTRACE, "VFS Op:name=%s, flags=%u\n",
               dentry->d_name.name, flags);
 
-       if (!(flags & (LOOKUP_PARENT|LOOKUP_OPEN|LOOKUP_CREATE)) &&
-           ll_need_statahead(parent, dentry) > 0) {
-               if (flags & LOOKUP_RCU)
-                       return -ECHILD;
-
-               if (dentry->d_inode == NULL)
-                       unplug = 1;
-               do_statahead_enter(parent, &dentry, unplug);
-               ll_statahead_mark(parent, dentry);
-       }
-
-       return 1;
+       rc = ll_revalidate_dentry(dentry, flags);
+       return rc;
 }
 
 
index 7ceec740ece51716f78bdd274f442e51a0ff4582..70b48ab30fe87916a7e11eecfc0ce8dad50a8031 100644 (file)
@@ -446,8 +446,7 @@ static int ll_intent_file_open(struct file *file, void *lmm,
                                 itp, NULL);
 
 out:
-       ptlrpc_req_finished(itp->d.lustre.it_data);
-       it_clear_disposition(itp, DISP_ENQ_COMPLETE);
+       ptlrpc_req_finished(req);
        ll_intent_drop_lock(itp);
 
        return rc;
@@ -815,10 +814,7 @@ struct obd_client_handle *ll_lease_open(struct inode *inode, struct file *file,
         * doesn't deal with openhandle, so normal openhandle will be leaked. */
                                LDLM_FL_NO_LRU | LDLM_FL_EXCL);
        ll_finish_md_op_data(op_data);
-       if (req != NULL) {
-               ptlrpc_req_finished(req);
-               it_clear_disposition(&it, DISP_ENQ_COMPLETE);
-       }
+       ptlrpc_req_finished(req);
        if (rc < 0)
                GOTO(out_release_it, rc);
 
index 47c514293691a519d933981390dc168225ec99f2..f67c50829437d41a986759a4a617170dd909e934 100644 (file)
@@ -1309,7 +1309,7 @@ ll_statahead_mark(struct inode *dir, struct dentry *dentry)
 }
 
 static inline int
-ll_need_statahead(struct inode *dir, struct dentry *dentryp)
+d_need_statahead(struct inode *dir, struct dentry *dentryp)
 {
        struct ll_inode_info  *lli;
        struct ll_dentry_data *ldd;
@@ -1354,7 +1354,7 @@ ll_statahead_enter(struct inode *dir, struct dentry **dentryp, int only_unplug)
 {
        int ret;
 
-       ret = ll_need_statahead(dir, *dentryp);
+       ret = d_need_statahead(dir, *dentryp);
        if (ret <= 0)
                return ret;
 
index 56dedceaf0a0c519adf0c4bb9d7e75efc5c1c364..9ba5a0a573909bb022f3426aa52ecadef2515b9d 100644 (file)
@@ -119,7 +119,6 @@ static int lmv_intent_remote(struct obd_export *exp, void *lmm,
        CDEBUG(D_INODE, "REMOTE_INTENT with fid="DFID" -> mds #%d\n",
               PFID(&body->fid1), tgt->ltd_idx);
 
-       it->d.lustre.it_disposition &= ~DISP_ENQ_COMPLETE;
        rc = md_intent_lock(tgt->ltd_exp, op_data, lmm, lmmsize, it,
                            flags, &req, cb_blocking, extra_lock_flags);
        if (rc)
index 40fbd44bdda1d6062886bcc8ad740d1fc0a6ea33..3ba0a0a1d945f9be02cf4c1a9238acb6cd8e1530 100644 (file)
@@ -1744,7 +1744,6 @@ lmv_enqueue_remote(struct obd_export *exp, struct ldlm_enqueue_info *einfo,
        it->d.lustre.it_data = NULL;
        fid1 = body->fid1;
 
-       it->d.lustre.it_disposition &= ~DISP_ENQ_COMPLETE;
        ptlrpc_req_finished(req);
 
        tgt = lmv_find_target(lmv, &fid1);
index 20706e788de909e1a44c9af2e39c5fba1cff5179..81adc2b8298706553d6a9ac7feff07a14eb90ee2 100644 (file)
@@ -968,7 +968,6 @@ static int mdc_finish_intent_lock(struct obd_export *exp,
        if (fid_is_sane(&op_data->op_fid2) &&
            it->it_create_mode & M_CHECK_STALE &&
            it->it_op != IT_GETATTR) {
-               it_set_disposition(it, DISP_ENQ_COMPLETE);
 
                /* Also: did we find the same inode? */
                /* sever can return one of two fids:
@@ -1139,6 +1138,12 @@ int mdc_intent_lock(struct obd_export *exp, struct md_op_data *op_data,
                    ldlm_blocking_callback cb_blocking,
                    __u64 extra_lock_flags)
 {
+       struct ldlm_enqueue_info einfo = {
+               .ei_type        = LDLM_IBITS,
+               .ei_mode        = it_to_lock_mode(it),
+               .ei_cb_bl       = cb_blocking,
+               .ei_cb_cp       = ldlm_completion_ast,
+       };
        struct lustre_handle lockh;
        int rc = 0;
 
@@ -1164,42 +1169,19 @@ int mdc_intent_lock(struct obd_export *exp, struct md_op_data *op_data,
                        return rc;
        }
 
-       /* lookup_it may be called only after revalidate_it has run, because
-        * revalidate_it cannot return errors, only zero.  Returning zero causes
-        * this call to lookup, which *can* return an error.
-        *
-        * We only want to execute the request associated with the intent one
-        * time, however, so don't send the request again.  Instead, skip past
-        * this and use the request from revalidate.  In this case, revalidate
-        * never dropped its reference, so the refcounts are all OK */
-       if (!it_disposition(it, DISP_ENQ_COMPLETE)) {
-               struct ldlm_enqueue_info einfo = {
-                       .ei_type        = LDLM_IBITS,
-                       .ei_mode        = it_to_lock_mode(it),
-                       .ei_cb_bl       = cb_blocking,
-                       .ei_cb_cp       = ldlm_completion_ast,
-               };
-
-               /* For case if upper layer did not alloc fid, do it now. */
-               if (!fid_is_sane(&op_data->op_fid2) && it->it_op & IT_CREAT) {
-                       rc = mdc_fid_alloc(exp, &op_data->op_fid2, op_data);
-                       if (rc < 0) {
-                               CERROR("Can't alloc new fid, rc %d\n", rc);
-                               return rc;
-                       }
-               }
-               rc = mdc_enqueue(exp, &einfo, it, op_data, &lockh,
-                                lmm, lmmsize, NULL, extra_lock_flags);
-               if (rc < 0)
+       /* For case if upper layer did not alloc fid, do it now. */
+       if (!fid_is_sane(&op_data->op_fid2) && it->it_op & IT_CREAT) {
+               rc = mdc_fid_alloc(exp, &op_data->op_fid2, op_data);
+               if (rc < 0) {
+                       CERROR("Can't alloc new fid, rc %d\n", rc);
                        return rc;
-       } else if (!fid_is_sane(&op_data->op_fid2) ||
-                  !(it->it_create_mode & M_CHECK_STALE)) {
-               /* DISP_ENQ_COMPLETE set means there is extra reference on
-                * request referenced from this intent, saved for subsequent
-                * lookup.  This path is executed when we proceed to this
-                * lookup, so we clear DISP_ENQ_COMPLETE */
-               it_clear_disposition(it, DISP_ENQ_COMPLETE);
+               }
        }
+       rc = mdc_enqueue(exp, &einfo, it, op_data, &lockh, lmm, lmmsize, NULL,
+                        extra_lock_flags);
+       if (rc < 0)
+               return rc;
+
        *reqp = it->d.lustre.it_data;
        rc = mdc_finish_intent_lock(exp, *reqp, op_data, it, &lockh);
        return rc;
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