If ff_layout_pg_get_read()'s attempt to get a layout segment results
in -EAGAIN have ff_layout_pg_init_read() retry it after sleeping.
If "softerr" mount is used, use 'io_maxretrans' to limit the number of
attempts to get a layout segment.
This fixes a long-standing issue of O_DIRECT reads failing with
-EAGAIN (11) when using flexfiles Client Side Mirroring (CSM).
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx>
---
fs/nfs/flexfilelayout/flexfilelayout.c | 27 ++++++++++++++++++++------
1 file changed, 21 insertions(+), 6 deletions(-)
diff --git a/fs/nfs/flexfilelayout/flexfilelayout.c b/fs/nfs/flexfilelayout/flexfilelayout.c
index ce61bf1ada6c..98b45b636be3 100644
--- a/fs/nfs/flexfilelayout/flexfilelayout.c
+++ b/fs/nfs/flexfilelayout/flexfilelayout.c
@@ -848,6 +848,9 @@ ff_layout_pg_init_read(struct nfs_pageio_descriptor *pgio,
struct nfs4_pnfs_ds *ds;
u32 ds_idx;
+ if (NFS_SERVER(pgio->pg_inode)->flags &
+ (NFS_MOUNT_SOFT|NFS_MOUNT_SOFTERR))
+ pgio->pg_maxretrans = io_maxretrans;
retry:
pnfs_generic_pg_check_layout(pgio, req);
/* Use full layout for now */
@@ -861,6 +864,8 @@ ff_layout_pg_init_read(struct nfs_pageio_descriptor *pgio,
if (!pgio->pg_lseg)
goto out_nolseg;
}
+ /* Reset wb_nio, since getting layout segment was successful */
+ req->wb_nio = 0;
ds = ff_layout_get_ds_for_read(pgio, &ds_idx);
if (!ds) {
@@ -877,14 +882,24 @@ ff_layout_pg_init_read(struct nfs_pageio_descriptor *pgio,
pgm->pg_bsize = mirror->mirror_ds->ds_versions[0].rsize;
pgio->pg_mirror_idx = ds_idx;
-
- if (NFS_SERVER(pgio->pg_inode)->flags &
- (NFS_MOUNT_SOFT|NFS_MOUNT_SOFTERR))
- pgio->pg_maxretrans = io_maxretrans;
return;
out_nolseg:
- if (pgio->pg_error < 0)
- return;
+ if (pgio->pg_error < 0) {
+ if (pgio->pg_error != -EAGAIN)
+ return;
+ /* Retry getting layout segment if lower layer returned -EAGAIN */
+ if (pgio->pg_maxretrans && req->wb_nio++ > pgio->pg_maxretrans) {
+ if (NFS_SERVER(pgio->pg_inode)->flags & NFS_MOUNT_SOFTERR)
+ pgio->pg_error = -ETIMEDOUT;
+ else
+ pgio->pg_error = -EIO;
+ return;
+ }
+ pgio->pg_error = 0;
+ /* Sleep for 1 second before retrying */
+ ssleep(1);
+ goto retry;
+ }
out_mds:
trace_pnfs_mds_fallback_pg_init_read(pgio->pg_inode,
0, NFS4_MAX_UINT64, IOMODE_READ,
--
2.44.0
