* [V2 3/3] pnfs: pnfs_update_layout needs to consider if strict iomode checking is on
2016-05-25 14:31 [V2 0/3] FF_FLAGS_NO_READ_IO Tom Haynes
2016-05-25 14:31 ` [V2 1/3] nfs/flexfiles: Helper function to detect FF_FLAGS_NO_READ_IO Tom Haynes
2016-05-25 14:31 ` [V2 2/3] nfs/flexfiles: Use the layout segment for reading unless it a IOMODE_RW and reading is disabled Tom Haynes
@ 2016-05-25 14:31 ` Tom Haynes
2 siblings, 0 replies; 4+ messages in thread
From: Tom Haynes @ 2016-05-25 14:31 UTC (permalink / raw)
To: Trond Myklebust; +Cc: Linux NFS Mailing list, Anna Schumaker
As flexfiles has FF_FLAGS_NO_READ_IO, there is a need to generically
support enforcing that a IOMODE_RW segment will not allow READ I/O.
Signed-off-by: Tom Haynes <loghyr@primarydata.com>
---
fs/nfs/filelayout/filelayout.c | 2 ++
fs/nfs/flexfilelayout/flexfilelayout.c | 49 +++++++++++++++++++++++++---------
fs/nfs/pnfs.c | 34 ++++++++++++++---------
fs/nfs/pnfs.h | 1 +
4 files changed, 61 insertions(+), 25 deletions(-)
diff --git a/fs/nfs/filelayout/filelayout.c b/fs/nfs/filelayout/filelayout.c
index 3e50057..aa59757 100644
--- a/fs/nfs/filelayout/filelayout.c
+++ b/fs/nfs/filelayout/filelayout.c
@@ -890,6 +890,7 @@ filelayout_pg_init_read(struct nfs_pageio_descriptor *pgio,
0,
NFS4_MAX_UINT64,
IOMODE_READ,
+ false,
GFP_KERNEL);
if (IS_ERR(pgio->pg_lseg)) {
pgio->pg_error = PTR_ERR(pgio->pg_lseg);
@@ -915,6 +916,7 @@ filelayout_pg_init_write(struct nfs_pageio_descriptor *pgio,
0,
NFS4_MAX_UINT64,
IOMODE_RW,
+ false,
GFP_NOFS);
if (IS_ERR(pgio->pg_lseg)) {
pgio->pg_error = PTR_ERR(pgio->pg_lseg);
diff --git a/fs/nfs/flexfilelayout/flexfilelayout.c b/fs/nfs/flexfilelayout/flexfilelayout.c
index a7aeb74..0e8018b 100644
--- a/fs/nfs/flexfilelayout/flexfilelayout.c
+++ b/fs/nfs/flexfilelayout/flexfilelayout.c
@@ -821,6 +821,36 @@ ff_layout_choose_best_ds_for_read(struct pnfs_layout_segment *lseg,
}
static void
+ff_layout_pg_get_read(struct nfs_pageio_descriptor *pgio,
+ struct nfs_page *req,
+ bool strict_iomode)
+{
+retry_strict:
+ pnfs_put_lseg(pgio->pg_lseg);
+ pgio->pg_lseg = pnfs_update_layout(pgio->pg_inode,
+ req->wb_context,
+ 0,
+ NFS4_MAX_UINT64,
+ IOMODE_READ,
+ strict_iomode,
+ GFP_KERNEL);
+ if (IS_ERR(pgio->pg_lseg)) {
+ pgio->pg_error = PTR_ERR(pgio->pg_lseg);
+ pgio->pg_lseg = NULL;
+ }
+
+ /* If we don't have checking, do get a IOMODE_RW
+ * segment, and the server wants to avoid READs
+ * there, then retry!
+ */
+ if (pgio->pg_lseg && !strict_iomode &&
+ ff_layout_avoid_read_on_rw(pgio->pg_lseg)) {
+ strict_iomode = true;
+ goto retry_strict;
+ }
+}
+
+static void
ff_layout_pg_init_read(struct nfs_pageio_descriptor *pgio,
struct nfs_page *req)
{
@@ -830,19 +860,10 @@ ff_layout_pg_init_read(struct nfs_pageio_descriptor *pgio,
int ds_idx;
/* Use full layout for now */
- if (!pgio->pg_lseg || ff_layout_avoid_read_on_rw(pgio->pg_lseg)) {
- pnfs_put_lseg(pgio->pg_lseg);
- pgio->pg_lseg = pnfs_update_layout(pgio->pg_inode,
- req->wb_context,
- 0,
- NFS4_MAX_UINT64,
- IOMODE_READ,
- GFP_KERNEL);
- if (IS_ERR(pgio->pg_lseg)) {
- pgio->pg_error = PTR_ERR(pgio->pg_lseg);
- pgio->pg_lseg = NULL;
- }
- }
+ if (!pgio->pg_lseg)
+ ff_layout_pg_get_read(pgio, req, false);
+ else if (ff_layout_avoid_read_on_rw(pgio->pg_lseg))
+ ff_layout_pg_get_read(pgio, req, true);
/* If no lseg, fall back to read through mds */
if (pgio->pg_lseg == NULL)
@@ -894,6 +915,7 @@ ff_layout_pg_init_write(struct nfs_pageio_descriptor *pgio,
0,
NFS4_MAX_UINT64,
IOMODE_RW,
+ false,
GFP_NOFS);
if (IS_ERR(pgio->pg_lseg)) {
pgio->pg_error = PTR_ERR(pgio->pg_lseg);
@@ -952,6 +974,7 @@ ff_layout_pg_get_mirror_count_write(struct nfs_pageio_descriptor *pgio,
0,
NFS4_MAX_UINT64,
IOMODE_RW,
+ false,
GFP_NOFS);
if (IS_ERR(pgio->pg_lseg)) {
pgio->pg_error = PTR_ERR(pgio->pg_lseg);
diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index 79ae304..0c7e0d4 100644
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -1321,23 +1321,28 @@ out_existing:
/*
* iomode matching rules:
- * iomode lseg match
- * ----- ----- -----
- * ANY READ true
- * ANY RW true
- * RW READ false
- * RW RW true
- * READ READ true
- * READ RW true
+ * iomode lseg strict match
+ * iomode
+ * ----- ----- ------ -----
+ * ANY READ N/A true
+ * ANY RW N/A true
+ * RW READ N/A false
+ * RW RW N/A true
+ * READ READ N/A true
+ * READ RW true false
+ * READ RW false true
*/
static bool
pnfs_lseg_range_match(const struct pnfs_layout_range *ls_range,
- const struct pnfs_layout_range *range)
+ const struct pnfs_layout_range *range,
+ bool strict_iomode)
{
struct pnfs_layout_range range1;
if ((range->iomode == IOMODE_RW &&
ls_range->iomode != IOMODE_RW) ||
+ (range->iomode != ls_range->iomode &&
+ strict_iomode == true) ||
!pnfs_lseg_range_intersecting(ls_range, range))
return 0;
@@ -1352,7 +1357,8 @@ pnfs_lseg_range_match(const struct pnfs_layout_range *ls_range,
*/
static struct pnfs_layout_segment *
pnfs_find_lseg(struct pnfs_layout_hdr *lo,
- struct pnfs_layout_range *range)
+ struct pnfs_layout_range *range,
+ bool strict_iomode)
{
struct pnfs_layout_segment *lseg, *ret = NULL;
@@ -1361,7 +1367,8 @@ pnfs_find_lseg(struct pnfs_layout_hdr *lo,
list_for_each_entry(lseg, &lo->plh_segs, pls_list) {
if (test_bit(NFS_LSEG_VALID, &lseg->pls_flags) &&
!test_bit(NFS_LSEG_LAYOUTRETURN, &lseg->pls_flags) &&
- pnfs_lseg_range_match(&lseg->pls_range, range)) {
+ pnfs_lseg_range_match(&lseg->pls_range, range,
+ strict_iomode)) {
ret = pnfs_get_lseg(lseg);
break;
}
@@ -1478,6 +1485,7 @@ pnfs_update_layout(struct inode *ino,
loff_t pos,
u64 count,
enum pnfs_iomode iomode,
+ bool strict_iomode,
gfp_t gfp_flags)
{
struct pnfs_layout_range arg = {
@@ -1539,7 +1547,7 @@ lookup_again:
goto out_unlock;
}
- lseg = pnfs_find_lseg(lo, &arg);
+ lseg = pnfs_find_lseg(lo, &arg, strict_iomode);
if (lseg) {
trace_pnfs_update_layout(ino, pos, count, iomode, lo, lseg,
PNFS_UPDATE_LAYOUT_FOUND_CACHED);
@@ -1883,6 +1891,7 @@ pnfs_generic_pg_init_read(struct nfs_pageio_descriptor *pgio, struct nfs_page *r
req_offset(req),
rd_size,
IOMODE_READ,
+ false,
GFP_KERNEL);
if (IS_ERR(pgio->pg_lseg)) {
pgio->pg_error = PTR_ERR(pgio->pg_lseg);
@@ -1907,6 +1916,7 @@ pnfs_generic_pg_init_write(struct nfs_pageio_descriptor *pgio,
req_offset(req),
wb_size,
IOMODE_RW,
+ false,
GFP_NOFS);
if (IS_ERR(pgio->pg_lseg)) {
pgio->pg_error = PTR_ERR(pgio->pg_lseg);
diff --git a/fs/nfs/pnfs.h b/fs/nfs/pnfs.h
index f9f3331..b21bd0b 100644
--- a/fs/nfs/pnfs.h
+++ b/fs/nfs/pnfs.h
@@ -288,6 +288,7 @@ struct pnfs_layout_segment *pnfs_update_layout(struct inode *ino,
loff_t pos,
u64 count,
enum pnfs_iomode iomode,
+ bool strict_iomode,
gfp_t gfp_flags);
void pnfs_clear_layoutreturn_waitbit(struct pnfs_layout_hdr *lo);
--
1.8.3.1
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