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NFSv4.1 test the mdsthreshold hint parameters 

Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
This commit is contained in:
Andy Adamson 2012-05-23 05:02:37 -04:00 committed by Trond Myklebust
parent 2701d086db
commit d23d61c8d3
1 changed files with 79 additions and 0 deletions
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79
fs/nfs/pnfs.c
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@ -935,6 +935,81 @@ pnfs_find_lseg(struct pnfs_layout_hdr *lo,
return ret;
}
/*
* Use mdsthreshold hints set at each OPEN to determine if I/O should go
* to the MDS or over pNFS
*
* The nfs_inode read_io and write_io fields are cumulative counters reset
* when there are no layout segments. Note that in pnfs_update_layout iomode
* is set to IOMODE_READ for a READ request, and set to IOMODE_RW for a
* WRITE request.
*
* A return of true means use MDS I/O.
*
* From rfc 5661:
* If a file's size is smaller than the file size threshold, data accesses
* SHOULD be sent to the metadata server. If an I/O request has a length that
* is below the I/O size threshold, the I/O SHOULD be sent to the metadata
* server. If both file size and I/O size are provided, the client SHOULD
* reach or exceed both thresholds before sending its read or write
* requests to the data server.
*/
static bool pnfs_within_mdsthreshold(struct nfs_open_context *ctx,
struct inode *ino, int iomode)
{
struct nfs4_threshold *t = ctx->mdsthreshold;
struct nfs_inode *nfsi = NFS_I(ino);
loff_t fsize = i_size_read(ino);
bool size = false, size_set = false, io = false, io_set = false, ret = false;
if (t == NULL)
return ret;
dprintk("%s bm=0x%x rd_sz=%llu wr_sz=%llu rd_io=%llu wr_io=%llu\n",
__func__, t->bm, t->rd_sz, t->wr_sz, t->rd_io_sz, t->wr_io_sz);
switch (iomode) {
case IOMODE_READ:
if (t->bm & THRESHOLD_RD) {
dprintk("%s fsize %llu\n", __func__, fsize);
size_set = true;
if (fsize < t->rd_sz)
size = true;
}
if (t->bm & THRESHOLD_RD_IO) {
dprintk("%s nfsi->read_io %llu\n", __func__,
nfsi->read_io);
io_set = true;
if (nfsi->read_io < t->rd_io_sz)
io = true;
}
break;
case IOMODE_RW:
if (t->bm & THRESHOLD_WR) {
dprintk("%s fsize %llu\n", __func__, fsize);
size_set = true;
if (fsize < t->wr_sz)
size = true;
}
if (t->bm & THRESHOLD_WR_IO) {
dprintk("%s nfsi->write_io %llu\n", __func__,
nfsi->write_io);
io_set = true;
if (nfsi->write_io < t->wr_io_sz)
io = true;
}
break;
}
if (size_set && io_set) {
if (size && io)
ret = true;
} else if (size || io)
ret = true;
dprintk("<-- %s size %d io %d ret %d\n", __func__, size, io, ret);
return ret;
}
/*
* Layout segment is retreived from the server if not cached.
* The appropriate layout segment is referenced and returned to the caller.
@ -962,6 +1037,10 @@ pnfs_update_layout(struct inode *ino,
if (!pnfs_enabled_sb(NFS_SERVER(ino)))
return NULL;
if (pnfs_within_mdsthreshold(ctx, ino, iomode))
return NULL;
spin_lock(&ino->i_lock);
lo = pnfs_find_alloc_layout(ino, ctx, gfp_flags);
if (lo == NULL) {