5.15-stable review patch. If anyone has any objections, please let me know.
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From: Mike Snitzer snitzer@kernel.org
commit eb3fabde15bccdf34f1c9b35a83aa4c0dacbb4ca upstream.
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@vger.kernel.org Signed-off-by: Mike Snitzer snitzer@kernel.org Signed-off-by: Anna Schumaker anna.schumaker@oracle.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/nfs/flexfilelayout/flexfilelayout.c | 27 +++++++++++++++++++++------ 1 file changed, 21 insertions(+), 6 deletions(-)
--- a/fs/nfs/flexfilelayout/flexfilelayout.c +++ b/fs/nfs/flexfilelayout/flexfilelayout.c @@ -836,6 +836,9 @@ ff_layout_pg_init_read(struct nfs_pageio 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: ff_layout_pg_check_layout(pgio, req); /* Use full layout for now */ @@ -849,6 +852,8 @@ retry: 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) { @@ -865,14 +870,24 @@ retry: 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,