2016-01-21 20:55:38

by Trond Myklebust

[permalink] [raw]
Subject: [PATCH 1/2] pNFS/flexfiles: Improve merging of errors in LAYOUTRETURN

When we hit 22 errors, we start to overflow the memory buffers allocated
to the LAYOUTRETURN errors. The issue is that currently, RPC call reply
ordering determines how successful we are in merging errors that refer
to contiguous READ or WRITE requests.

Fix is to use an insertion sort to help detect contiguity.

Signed-off-by: Trond Myklebust <[email protected]>
---
fs/nfs/flexfilelayout/flexfilelayoutdev.c | 99 +++++++++++++------------------
1 file changed, 40 insertions(+), 59 deletions(-)

diff --git a/fs/nfs/flexfilelayout/flexfilelayoutdev.c b/fs/nfs/flexfilelayout/flexfilelayoutdev.c
index e125e55de86d..bcf79aad86fc 100644
--- a/fs/nfs/flexfilelayout/flexfilelayoutdev.c
+++ b/fs/nfs/flexfilelayout/flexfilelayoutdev.c
@@ -218,63 +218,55 @@ static void extend_ds_error(struct nfs4_ff_layout_ds_err *err,
err->length = end - err->offset;
}

-static bool ds_error_can_merge(struct nfs4_ff_layout_ds_err *err, u64 offset,
- u64 length, int status, enum nfs_opnum4 opnum,
- nfs4_stateid *stateid,
- struct nfs4_deviceid *deviceid)
+static int
+ff_ds_error_match(const struct nfs4_ff_layout_ds_err *e1,
+ const struct nfs4_ff_layout_ds_err *e2)
{
- return err->status == status && err->opnum == opnum &&
- nfs4_stateid_match(&err->stateid, stateid) &&
- !memcmp(&err->deviceid, deviceid, sizeof(*deviceid)) &&
- end_offset(err->offset, err->length) >= offset &&
- err->offset <= end_offset(offset, length);
-}
-
-static bool merge_ds_error(struct nfs4_ff_layout_ds_err *old,
- struct nfs4_ff_layout_ds_err *new)
-{
- if (!ds_error_can_merge(old, new->offset, new->length, new->status,
- new->opnum, &new->stateid, &new->deviceid))
- return false;
-
- extend_ds_error(old, new->offset, new->length);
- return true;
+ int ret;
+
+ if (e1->opnum != e2->opnum)
+ return e1->opnum < e2->opnum ? -1 : 1;
+ if (e1->status != e2->status)
+ return e1->status < e2->status ? -1 : 1;
+ ret = memcmp(&e1->stateid, &e2->stateid, sizeof(e1->stateid));
+ if (ret != 0)
+ return ret;
+ ret = memcmp(&e1->deviceid, &e2->deviceid, sizeof(e1->deviceid));
+ if (ret != 0)
+ return ret;
+ if (end_offset(e1->offset, e1->length) < e2->offset)
+ return -1;
+ if (e1->offset > end_offset(e2->offset, e2->length))
+ return 1;
+ /* If ranges overlap or are contiguous, they are the same */
+ return 0;
}

-static bool
+static void
ff_layout_add_ds_error_locked(struct nfs4_flexfile_layout *flo,
struct nfs4_ff_layout_ds_err *dserr)
{
- struct nfs4_ff_layout_ds_err *err;
-
- list_for_each_entry(err, &flo->error_list, list) {
- if (merge_ds_error(err, dserr)) {
- return true;
- }
- }
-
- list_add(&dserr->list, &flo->error_list);
- return false;
-}
-
-static bool
-ff_layout_update_ds_error(struct nfs4_flexfile_layout *flo, u64 offset,
- u64 length, int status, enum nfs_opnum4 opnum,
- nfs4_stateid *stateid, struct nfs4_deviceid *deviceid)
-{
- bool found = false;
- struct nfs4_ff_layout_ds_err *err;
-
- list_for_each_entry(err, &flo->error_list, list) {
- if (ds_error_can_merge(err, offset, length, status, opnum,
- stateid, deviceid)) {
- found = true;
- extend_ds_error(err, offset, length);
+ struct nfs4_ff_layout_ds_err *err, *tmp;
+ struct list_head *head = &flo->error_list;
+ int match;
+
+ /* Do insertion sort w/ merges */
+ list_for_each_entry_safe(err, tmp, &flo->error_list, list) {
+ match = ff_ds_error_match(err, dserr);
+ if (match < 0)
+ continue;
+ if (match > 0) {
+ /* Add entry "dserr" _before_ entry "err" */
+ head = &err->list;
break;
}
+ /* Entries match, so merge "err" into "dserr" */
+ extend_ds_error(dserr, err->offset, err->length);
+ list_del(&err->list);
+ kfree(err);
}

- return found;
+ list_add_tail(&dserr->list, head);
}

int ff_layout_track_ds_error(struct nfs4_flexfile_layout *flo,
@@ -283,7 +275,6 @@ int ff_layout_track_ds_error(struct nfs4_flexfile_layout *flo,
gfp_t gfp_flags)
{
struct nfs4_ff_layout_ds_err *dserr;
- bool needfree;

if (status == 0)
return 0;
@@ -291,14 +282,6 @@ int ff_layout_track_ds_error(struct nfs4_flexfile_layout *flo,
if (mirror->mirror_ds == NULL)
return -EINVAL;

- spin_lock(&flo->generic_hdr.plh_inode->i_lock);
- if (ff_layout_update_ds_error(flo, offset, length, status, opnum,
- &mirror->stateid,
- &mirror->mirror_ds->id_node.deviceid)) {
- spin_unlock(&flo->generic_hdr.plh_inode->i_lock);
- return 0;
- }
- spin_unlock(&flo->generic_hdr.plh_inode->i_lock);
dserr = kmalloc(sizeof(*dserr), gfp_flags);
if (!dserr)
return -ENOMEM;
@@ -313,10 +296,8 @@ int ff_layout_track_ds_error(struct nfs4_flexfile_layout *flo,
NFS4_DEVICEID4_SIZE);

spin_lock(&flo->generic_hdr.plh_inode->i_lock);
- needfree = ff_layout_add_ds_error_locked(flo, dserr);
+ ff_layout_add_ds_error_locked(flo, dserr);
spin_unlock(&flo->generic_hdr.plh_inode->i_lock);
- if (needfree)
- kfree(dserr);

return 0;
}
--
2.5.0



2016-01-21 20:55:39

by Trond Myklebust

[permalink] [raw]
Subject: [PATCH 2/2] pNFS/flexfiles: Fix an XDR encoding bug in layoutreturn

We must not skip encoding the statistics, or the server will see an
XDR encoding error.

Signed-off-by: Trond Myklebust <[email protected]>
Cc: [email protected] # 4.0+
---
fs/nfs/flexfilelayout/flexfilelayout.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/fs/nfs/flexfilelayout/flexfilelayout.c b/fs/nfs/flexfilelayout/flexfilelayout.c
index 405f46ba490e..82959409b9a6 100644
--- a/fs/nfs/flexfilelayout/flexfilelayout.c
+++ b/fs/nfs/flexfilelayout/flexfilelayout.c
@@ -1859,9 +1859,7 @@ ff_layout_encode_layoutreturn(struct pnfs_layout_hdr *lo,
start = xdr_reserve_space(xdr, 4);
BUG_ON(!start);

- if (ff_layout_encode_ioerr(flo, xdr, args))
- goto out;
-
+ ff_layout_encode_ioerr(flo, xdr, args);
ff_layout_encode_iostats(flo, xdr, args);
out:
*start = cpu_to_be32((xdr->p - start - 1) * 4);
--
2.5.0


2016-01-22 14:39:19

by Anna Schumaker

[permalink] [raw]
Subject: Re: [PATCH 2/2] pNFS/flexfiles: Fix an XDR encoding bug in layoutreturn

Hi Trond,

On 01/21/2016 03:55 PM, Trond Myklebust wrote:
> We must not skip encoding the statistics, or the server will see an
> XDR encoding error.
>
> Signed-off-by: Trond Myklebust <[email protected]>
> Cc: [email protected] # 4.0+
> ---
> fs/nfs/flexfilelayout/flexfilelayout.c | 4 +---
> 1 file changed, 1 insertion(+), 3 deletions(-)
>
> diff --git a/fs/nfs/flexfilelayout/flexfilelayout.c b/fs/nfs/flexfilelayout/flexfilelayout.c
> index 405f46ba490e..82959409b9a6 100644
> --- a/fs/nfs/flexfilelayout/flexfilelayout.c
> +++ b/fs/nfs/flexfilelayout/flexfilelayout.c
> @@ -1859,9 +1859,7 @@ ff_layout_encode_layoutreturn(struct pnfs_layout_hdr *lo,
> start = xdr_reserve_space(xdr, 4);
> BUG_ON(!start);
>
> - if (ff_layout_encode_ioerr(flo, xdr, args))
> - goto out;

Can you remove the label "out", too? GCC tells me:

fs/nfs/flexfilelayout/flexfilelayout.c:1953:1: error: label 'out' defined but not used [-Werror=unused-label]

Thanks,
Anna

> -
> + ff_layout_encode_ioerr(flo, xdr, args);
> ff_layout_encode_iostats(flo, xdr, args);
> out:
> *start = cpu_to_be32((xdr->p - start - 1) * 4);
>


2016-01-22 16:05:03

by Trond Myklebust

[permalink] [raw]
Subject: Re: [PATCH 2/2] pNFS/flexfiles: Fix an XDR encoding bug in layoutreturn

On Fri, Jan 22, 2016 at 9:38 AM, Anna Schumaker
<[email protected]> wrote:
>
> Hi Trond,
>
> On 01/21/2016 03:55 PM, Trond Myklebust wrote:
> > We must not skip encoding the statistics, or the server will see an
> > XDR encoding error.
> >
> > Signed-off-by: Trond Myklebust <[email protected]>
> > Cc: [email protected] # 4.0+
> > ---
> > fs/nfs/flexfilelayout/flexfilelayout.c | 4 +---
> > 1 file changed, 1 insertion(+), 3 deletions(-)
> >
> > diff --git a/fs/nfs/flexfilelayout/flexfilelayout.c b/fs/nfs/flexfilelayout/flexfilelayout.c
> > index 405f46ba490e..82959409b9a6 100644
> > --- a/fs/nfs/flexfilelayout/flexfilelayout.c
> > +++ b/fs/nfs/flexfilelayout/flexfilelayout.c
> > @@ -1859,9 +1859,7 @@ ff_layout_encode_layoutreturn(struct pnfs_layout_hdr *lo,
> > start = xdr_reserve_space(xdr, 4);
> > BUG_ON(!start);
> >
> > - if (ff_layout_encode_ioerr(flo, xdr, args))
> > - goto out;
>
> Can you remove the label "out", too? GCC tells me:
>
> fs/nfs/flexfilelayout/flexfilelayout.c:1953:1: error: label 'out' defined but not used [-Werror=unused-label]
>

I intended to do this, but it slipped my mind. Done now...

Apologies
Trond