lkml.org 
[lkml]   [2014]   [Feb]   [28]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 09/17] lustre/llite: simplify dentry revalidate
Date
From: Lai Siyao <lai.siyao@intel.com>

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>
---
.../lustre/lustre/include/lustre/lustre_idl.h | 2 +-
drivers/staging/lustre/lustre/llite/dcache.c | 290 ++-------------------
drivers/staging/lustre/lustre/llite/file.c | 8 +-
.../staging/lustre/lustre/llite/llite_internal.h | 4 +-
drivers/staging/lustre/lustre/lmv/lmv_intent.c | 1 -
drivers/staging/lustre/lustre/lmv/lmv_obd.c | 1 -
drivers/staging/lustre/lustre/mdc/mdc_locks.c | 52 ++--
7 files changed, 45 insertions(+), 313 deletions(-)

diff --git a/drivers/staging/lustre/lustre/include/lustre/lustre_idl.h b/drivers/staging/lustre/lustre/include/lustre/lustre_idl.h
index a55eebf..5f5b0ba 100644
--- a/drivers/staging/lustre/lustre/include/lustre/lustre_idl.h
+++ b/drivers/staging/lustre/lustre/include/lustre/lustre_idl.h
@@ -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
diff --git a/drivers/staging/lustre/lustre/llite/dcache.c b/drivers/staging/lustre/lustre/llite/dcache.c
index 3907c87..f971a54 100644
--- a/drivers/staging/lustre/lustre/llite/dcache.c
+++ b/drivers/staging/lustre/lustre/llite/dcache.c
@@ -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;
}


diff --git a/drivers/staging/lustre/lustre/llite/file.c b/drivers/staging/lustre/lustre/llite/file.c
index 7ceec74..70b48ab 100644
--- a/drivers/staging/lustre/lustre/llite/file.c
+++ b/drivers/staging/lustre/lustre/llite/file.c
@@ -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);

diff --git a/drivers/staging/lustre/lustre/llite/llite_internal.h b/drivers/staging/lustre/lustre/llite/llite_internal.h
index 47c5142..f67c508 100644
--- a/drivers/staging/lustre/lustre/llite/llite_internal.h
+++ b/drivers/staging/lustre/lustre/llite/llite_internal.h
@@ -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;

diff --git a/drivers/staging/lustre/lustre/lmv/lmv_intent.c b/drivers/staging/lustre/lustre/lmv/lmv_intent.c
index 56dedce..9ba5a0a 100644
--- a/drivers/staging/lustre/lustre/lmv/lmv_intent.c
+++ b/drivers/staging/lustre/lustre/lmv/lmv_intent.c
@@ -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)
diff --git a/drivers/staging/lustre/lustre/lmv/lmv_obd.c b/drivers/staging/lustre/lustre/lmv/lmv_obd.c
index 40fbd44..3ba0a0a 100644
--- a/drivers/staging/lustre/lustre/lmv/lmv_obd.c
+++ b/drivers/staging/lustre/lustre/lmv/lmv_obd.c
@@ -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);
diff --git a/drivers/staging/lustre/lustre/mdc/mdc_locks.c b/drivers/staging/lustre/lustre/mdc/mdc_locks.c
index 20706e7..81adc2b 100644
--- a/drivers/staging/lustre/lustre/mdc/mdc_locks.c
+++ b/drivers/staging/lustre/lustre/mdc/mdc_locks.c
@@ -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;
--
1.8.5.3


\
 
 \ /
  Last update: 2014-03-01 04:01    [W:0.090 / U:1.368 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site