Commit f06bedfa authored by Tigran Mkrtchyan's avatar Tigran Mkrtchyan Committed by Trond Myklebust
Browse files

pNFS/flexfiles: don't attempt pnfs on fatal DS errors 



When an applications get killed (SIGTERM/SIGINT) while pNFS client performs a connection
to DS, client ends in an infinite loop of connect-disconnect. This
source of the issue, it that flexfilelayoutdev#nfs4_ff_layout_prepare_ds gets an error
on nfs4_pnfs_ds_connect with status ERESTARTSYS, which is set by rpc_signal_task, but
the error is treated as transient, thus retried.

The issue is reproducible with Ctrl+C the following script(there should be ~1000 files in
a directory, client should must not have any connections to DSes):

```
echo 3 > /proc/sys/vm/drop_caches

for i in *
do
   head -1 $i
done
```

The change aims to propagate the nfs4_ff_layout_prepare_ds error state
to the caller that can decide whatever this is a retryable error or not.

Signed-off-by: default avatarTigran Mkrtchyan <tigran.mkrtchyan@desy.de>
Link: https://lore.kernel.org/r/20250627071751.189663-1-tigran.mkrtchyan@desy.de


Fixes: 260f32ad ("pNFS/flexfiles: Check the result of nfs4_pnfs_ds_connect")
Signed-off-by: default avatarTrond Myklebust <trond.myklebust@hammerspace.com>
parent c262b444

fs/nfs/flexfilelayout/flexfilelayout.c

+16 −10
Original line number Diff line number Diff line
@@ -762,14 +762,14 @@ ff_layout_choose_ds_for_read(struct pnfs_layout_segment *lseg, 
{

	struct nfs4_ff_layout_segment *fls = FF_LAYOUT_LSEG(lseg);

	struct nfs4_ff_layout_mirror *mirror;

	struct nfs4_pnfs_ds *ds;

	struct nfs4_pnfs_ds *ds = ERR_PTR(-EAGAIN);

	u32 idx;



	/* mirrors are initially sorted by efficiency */

	for (idx = start_idx; idx < fls->mirror_array_cnt; idx++) {

		mirror = FF_LAYOUT_COMP(lseg, idx);

		ds = nfs4_ff_layout_prepare_ds(lseg, mirror, false);

		if (!ds)

		if (IS_ERR(ds))

			continue;



		if (check_device &&
@@ -777,10 +777,10 @@ ff_layout_choose_ds_for_read(struct pnfs_layout_segment *lseg, 
			continue;



		*best_idx = idx;

		return ds;

		break;

	}



	return NULL;

	return ds;

}



static struct nfs4_pnfs_ds *
@@ -942,7 +942,7 @@ ff_layout_pg_init_write(struct nfs_pageio_descriptor *pgio, 
	for (i = 0; i < pgio->pg_mirror_count; i++) {

		mirror = FF_LAYOUT_COMP(pgio->pg_lseg, i);

		ds = nfs4_ff_layout_prepare_ds(pgio->pg_lseg, mirror, true);

		if (!ds) {

		if (IS_ERR(ds)) {

			if (!ff_layout_no_fallback_to_mds(pgio->pg_lseg))

				goto out_mds;

			pnfs_generic_pg_cleanup(pgio);
@@ -1867,6 +1867,7 @@ ff_layout_read_pagelist(struct nfs_pgio_header *hdr) 
	u32 idx = hdr->pgio_mirror_idx;

	int vers;

	struct nfs_fh *fh;

	bool ds_fatal_error = false;



	dprintk("--> %s ino %lu pgbase %u req %zu@%llu\n",

		__func__, hdr->inode->i_ino,
@@ -1874,8 +1875,10 @@ ff_layout_read_pagelist(struct nfs_pgio_header *hdr) 


	mirror = FF_LAYOUT_COMP(lseg, idx);

	ds = nfs4_ff_layout_prepare_ds(lseg, mirror, false);

	if (!ds)

	if (IS_ERR(ds)) {

		ds_fatal_error = nfs_error_is_fatal(PTR_ERR(ds));

		goto out_failed;

	}



	ds_clnt = nfs4_ff_find_or_create_ds_client(mirror, ds->ds_clp,

						   hdr->inode);
@@ -1923,7 +1926,7 @@ ff_layout_read_pagelist(struct nfs_pgio_header *hdr) 
	return PNFS_ATTEMPTED;



out_failed:

	if (ff_layout_avoid_mds_available_ds(lseg))

	if (ff_layout_avoid_mds_available_ds(lseg) && !ds_fatal_error)

		return PNFS_TRY_AGAIN;

	trace_pnfs_mds_fallback_read_pagelist(hdr->inode,

			hdr->args.offset, hdr->args.count,
@@ -1945,11 +1948,14 @@ ff_layout_write_pagelist(struct nfs_pgio_header *hdr, int sync) 
	int vers;

	struct nfs_fh *fh;

	u32 idx = hdr->pgio_mirror_idx;

	bool ds_fatal_error = false;



	mirror = FF_LAYOUT_COMP(lseg, idx);

	ds = nfs4_ff_layout_prepare_ds(lseg, mirror, true);

	if (!ds)

	if (IS_ERR(ds)) {

		ds_fatal_error = nfs_error_is_fatal(PTR_ERR(ds));

		goto out_failed;

	}



	ds_clnt = nfs4_ff_find_or_create_ds_client(mirror, ds->ds_clp,

						   hdr->inode);
@@ -2000,7 +2006,7 @@ ff_layout_write_pagelist(struct nfs_pgio_header *hdr, int sync) 
	return PNFS_ATTEMPTED;



out_failed:

	if (ff_layout_avoid_mds_available_ds(lseg))

	if (ff_layout_avoid_mds_available_ds(lseg) && !ds_fatal_error)

		return PNFS_TRY_AGAIN;

	trace_pnfs_mds_fallback_write_pagelist(hdr->inode,

			hdr->args.offset, hdr->args.count,
@@ -2043,7 +2049,7 @@ static int ff_layout_initiate_commit(struct nfs_commit_data *data, int how) 
	idx = calc_ds_index_from_commit(lseg, data->ds_commit_index);

	mirror = FF_LAYOUT_COMP(lseg, idx);

	ds = nfs4_ff_layout_prepare_ds(lseg, mirror, true);

	if (!ds)

	if (IS_ERR(ds))

		goto out_err;



	ds_clnt = nfs4_ff_find_or_create_ds_client(mirror, ds->ds_clp,

fs/nfs/flexfilelayout/flexfilelayoutdev.c

+3 −3
Original line number Diff line number Diff line
@@ -370,11 +370,11 @@ nfs4_ff_layout_prepare_ds(struct pnfs_layout_segment *lseg, 
			  struct nfs4_ff_layout_mirror *mirror,

			  bool fail_return)

{

	struct nfs4_pnfs_ds *ds = NULL;

	struct nfs4_pnfs_ds *ds;

	struct inode *ino = lseg->pls_layout->plh_inode;

	struct nfs_server *s = NFS_SERVER(ino);

	unsigned int max_payload;

	int status;

	int status = -EAGAIN;



	if (!ff_layout_init_mirror_ds(lseg->pls_layout, mirror))

		goto noconnect;
@@ -418,7 +418,7 @@ nfs4_ff_layout_prepare_ds(struct pnfs_layout_segment *lseg, 
	ff_layout_send_layouterror(lseg);

	if (fail_return || !ff_layout_has_available_ds(lseg))

		pnfs_error_mark_layout_for_return(ino, lseg);

	ds = NULL;

	ds = ERR_PTR(status);

out:

	return ds;

}