On 06/30/2010 12:05 PM, Boaz Harrosh wrote:
> On 06/29/2010 07:42 PM, andros@xxxxxxxxxx wrote:
>> From: Andy Adamson <andros@xxxxxxxxxx>
>>
>> Prepare to embed struct pnfs_layout_tupe into layout driver private structs
>> and to make layout a pointer: state flags need to be accessible before
>> allocation.
>>
>
> I don't get that. A pointer inspection operation is atomic. (gone are the
> days of 16-bit large/huge models where a pointer is two registers.)
>
> So an: if (lo->pointer) is just as atomic as test_bit()
>
> And I don't see, not here, and not in the next patch, where are these used before
> the allocation. if you throw away Fred's first patch and make:
> layoutcommit_needed(struct nfs_inode *nfsi)
> {
> - return nfsi->layout.lo_cred != NULL;
> + return nfsi->layout != NULL;
> }
>
Rrrr need my morning coffee, sorry.
But still, Fred's patch can go both sites of the pointer assignment have an
MB and a pointer inspection is there-for atomic. Above can then be:
layoutcommit_needed(struct nfs_inode *nfsi)
{
- return nfsi->layout.lo_cred != NULL;
+ return nfsi->layout && (nfsi->layout->lo_cred != NULL);
}
> Then all three patches (first one thrown away) can just collapse to a single
> embedded-to-pointer conversion.
>
This still applies
Boaz
> Boaz
>> Signed-off-by: Andy Adamson <andros@xxxxxxxxxx>
>> ---
>> fs/nfs/inode.c | 2 +-
>> fs/nfs/pnfs.c | 16 ++++++++--------
>> include/linux/nfs_fs.h | 10 +++++-----
>> 3 files changed, 14 insertions(+), 14 deletions(-)
>>
>> diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
>> index 7989dea..66d7be2 100644
>> --- a/fs/nfs/inode.c
>> +++ b/fs/nfs/inode.c
>> @@ -1364,7 +1364,6 @@ void nfs4_clear_inode(struct inode *inode)
>> static void pnfs_alloc_init_inode(struct nfs_inode *nfsi)
>> {
>> #ifdef CONFIG_NFS_V4_1
>> - nfsi->layout.pnfs_layout_state = 0;
>> memset(&nfsi->layout.stateid, 0, NFS4_STATEID_SIZE);
>> nfsi->layout.roc_iomode = 0;
>> nfsi->layout.lo_cred = NULL;
>> @@ -1420,6 +1419,7 @@ static void pnfs_init_once(struct nfs_inode *nfsi)
>> {
>> #ifdef CONFIG_NFS_V4_1
>> init_waitqueue_head(&nfsi->lo_waitq);
>> + nfsi->pnfs_layout_state = 0;
>> seqlock_init(&nfsi->layout.seqlock);
>> INIT_LIST_HEAD(&nfsi->layout.lo_layouts);
>> INIT_LIST_HEAD(&nfsi->layout.segs);
>> diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
>> index bf15b5c..d05cb03 100644
>> --- a/fs/nfs/pnfs.c
>> +++ b/fs/nfs/pnfs.c
>> @@ -951,7 +951,7 @@ get_lock_alloc_layout(struct inode *ino)
>> * wait until bit is cleared if we lost this race.
>> */
>> res = wait_on_bit_lock(
>> - &nfsi->layout.pnfs_layout_state,
>> + &nfsi->pnfs_layout_state,
>> NFS_INO_LAYOUT_ALLOC,
>> pnfs_wait_schedule, TASK_KILLABLE);
>> if (res) {
>> @@ -975,8 +975,8 @@ get_lock_alloc_layout(struct inode *ino)
>>
>> /* release the NFS_INO_LAYOUT_ALLOC bit and wake up waiters */
>> clear_bit_unlock(NFS_INO_LAYOUT_ALLOC,
>> - &nfsi->layout.pnfs_layout_state);
>> - wake_up_bit(&nfsi->layout.pnfs_layout_state,
>> + &nfsi->pnfs_layout_state);
>> + wake_up_bit(&nfsi->pnfs_layout_state,
>> NFS_INO_LAYOUT_ALLOC);
>> break;
>> }
>> @@ -1104,12 +1104,12 @@ _pnfs_update_layout(struct inode *ino,
>> }
>>
>> /* if get layout already failed once goto out */
>> - if (test_bit(lo_fail_bit(iomode), &nfsi->layout.pnfs_layout_state)) {
>> + if (test_bit(lo_fail_bit(iomode), &nfsi->pnfs_layout_state)) {
>> if (unlikely(nfsi->layout.pnfs_layout_suspend &&
>> get_seconds() >= nfsi->layout.pnfs_layout_suspend)) {
>> dprintk("%s: layout_get resumed\n", __func__);
>> clear_bit(lo_fail_bit(iomode),
>> - &nfsi->layout.pnfs_layout_state);
>> + &nfsi->pnfs_layout_state);
>> nfsi->layout.pnfs_layout_suspend = 0;
>> } else
>> goto out_put;
>> @@ -1121,7 +1121,7 @@ _pnfs_update_layout(struct inode *ino,
>> send_layoutget(ino, ctx, &arg, lsegpp, lo);
>> out:
>> dprintk("%s end, state 0x%lx lseg %p\n", __func__,
>> - nfsi->layout.pnfs_layout_state, lseg);
>> + nfsi->pnfs_layout_state, lseg);
>> return;
>> out_put:
>> if (lsegpp)
>> @@ -1226,12 +1226,12 @@ pnfs_get_layout_done(struct nfs4_pnfs_layoutget *lgp, int rpc_status)
>> /* remember that get layout failed and suspend trying */
>> nfsi->layout.pnfs_layout_suspend = suspend;
>> set_bit(lo_fail_bit(lgp->args.lseg.iomode),
>> - &nfsi->layout.pnfs_layout_state);
>> + &nfsi->pnfs_layout_state);
>> dprintk("%s: layout_get suspended until %ld\n",
>> __func__, suspend);
>> out:
>> dprintk("%s end (err:%d) state 0x%lx lseg %p\n",
>> - __func__, lgp->status, nfsi->layout.pnfs_layout_state, lseg);
>> + __func__, lgp->status, nfsi->pnfs_layout_state, lseg);
>> return;
>> }
>>
>> diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h
>> index a33e86e..e216e24 100644
>> --- a/include/linux/nfs_fs.h
>> +++ b/include/linux/nfs_fs.h
>> @@ -105,11 +105,6 @@ struct pnfs_layout_type {
>> seqlock_t seqlock; /* Protects the stateid */
>> nfs4_stateid stateid;
>> void *ld_data; /* layout driver private data */
>> - unsigned long pnfs_layout_state;
>> - #define NFS_INO_RO_LAYOUT_FAILED 0 /* get ro layout failed stop trying */
>> - #define NFS_INO_RW_LAYOUT_FAILED 1 /* get rw layout failed stop trying */
>> - #define NFS_INO_LAYOUT_ALLOC 2 /* bit lock for layout allocation */
>> - #define NFS_INO_LAYOUTCOMMIT 3 /* LAYOUTCOMMIT needed */
>> time_t pnfs_layout_suspend;
>> struct rpc_cred *lo_cred; /* layoutcommit credential */
>> /* DH: These vars keep track of the maximum write range
>> @@ -208,6 +203,11 @@ struct nfs_inode {
>> #if defined(CONFIG_NFS_V4_1)
>> wait_queue_head_t lo_waitq;
>> struct pnfs_layout_type layout;
>> + unsigned long pnfs_layout_state;
>> + #define NFS_INO_RO_LAYOUT_FAILED 0 /* ro LAYOUTGET failed stop trying */
>> + #define NFS_INO_RW_LAYOUT_FAILED 1 /* rw LAYOUTGET failed stop trying */
>> + #define NFS_INO_LAYOUT_ALLOC 2 /* bit lock for layout allocation */
>> + #define NFS_INO_LAYOUTCOMMIT 3 /* LAYOUTCOMMIT needed */
>> #endif /* CONFIG_NFS_V4_1 */
>> #endif /* CONFIG_NFS_V4*/
>> #ifdef CONFIG_NFS_FSCACHE
>
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