[PATCH AUTOSEL 5.2 48/94] NFS: Fix spurious EIO read errors

Sasha Levin
2019-09-04T15:58:57Z

From: Trond Myklebust <trond.myklebust@hammerspace.com>

[ Upstream commit 8f54c7a4babf58bbaf849e126f7ae9664bdc9e04 ]

If the client attempts to read a page, but the read fails due to some
spurious error (e.g. an ACCESS error or a timeout, ...) then we need
to allow other processes to retry.
Also try to report errors correctly when doing a synchronous readpage.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/nfs/internal.h | 10 ++++++++++
fs/nfs/read.c | 35 ++++++++++++++++++++++++++---------
fs/nfs/write.c | 12 ------------
3 files changed, 36 insertions(+), 21 deletions(-)

diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
index 81e2fdff227ed..9ab9427405f3f 100644
--- a/fs/nfs/internal.h
+++ b/fs/nfs/internal.h
@@ -773,3 +773,13 @@ static inline bool nfs_error_is_fatal(int err)
}
}

+static inline bool nfs_error_is_fatal_on_server(int err)
+{
+ switch (err) {
+ case 0:
+ case -ERESTARTSYS:
+ case -EINTR:
+ return false;
+ }
+ return nfs_error_is_fatal(err);
+}
diff --git a/fs/nfs/read.c b/fs/nfs/read.c
index c19841c82b6a3..cfe0b586eadd4 100644
--- a/fs/nfs/read.c
+++ b/fs/nfs/read.c
@@ -91,19 +91,25 @@ void nfs_pageio_reset_read_mds(struct nfs_pageio_descriptor *pgio)
}
EXPORT_SYMBOL_GPL(nfs_pageio_reset_read_mds);

-static void nfs_readpage_release(struct nfs_page *req)
+static void nfs_readpage_release(struct nfs_page *req, int error)
{
struct inode *inode = d_inode(nfs_req_openctx(req)->dentry);
+ struct page *page = req->wb_page;

dprintk("NFS: read done (%s/%llu %d@%lld)\n", inode->i_sb->s_id,
(unsigned long long)NFS_FILEID(inode), req->wb_bytes,
(long long)req_offset(req));

+ if (nfs_error_is_fatal_on_server(error) && error != -ETIMEDOUT)
+ SetPageError(page);
if (nfs_page_group_sync_on_bit(req, PG_UNLOCKPAGE)) {
- if (PageUptodate(req->wb_page))
- nfs_readpage_to_fscache(inode, req->wb_page, 0);
+ struct address_space *mapping = page_file_mapping(page);

- unlock_page(req->wb_page);
+ if (PageUptodate(page))
+ nfs_readpage_to_fscache(inode, page, 0);
+ else if (!PageError(page) && !PagePrivate(page))
+ generic_error_remove_page(mapping, page);
+ unlock_page(page);
}
nfs_release_request(req);
}
@@ -131,7 +137,7 @@ int nfs_readpage_async(struct nfs_open_context *ctx, struct inode *inode,
&nfs_async_read_completion_ops);
if (!nfs_pageio_add_request(&pgio, new)) {
nfs_list_remove_request(new);
- nfs_readpage_release(new);
+ nfs_readpage_release(new, pgio.pg_error);
}
nfs_pageio_complete(&pgio);

@@ -153,6 +159,7 @@ static void nfs_page_group_set_uptodate(struct nfs_page *req)
static void nfs_read_completion(struct nfs_pgio_header *hdr)
{
unsigned long bytes = 0;
+ int error;

if (test_bit(NFS_IOHDR_REDO, &hdr->flags))
goto out;
@@ -179,14 +186,19 @@ static void nfs_read_completion(struct nfs_pgio_header *hdr)
zero_user_segment(page, start, end);
}
}
+ error = 0;
bytes += req->wb_bytes;
if (test_bit(NFS_IOHDR_ERROR, &hdr->flags)) {
if (bytes <= hdr->good_bytes)
nfs_page_group_set_uptodate(req);
+ else {
+ error = hdr->error;
+ xchg(&nfs_req_openctx(req)->error, error);
+ }
} else
nfs_page_group_set_uptodate(req);
nfs_list_remove_request(req);
- nfs_readpage_release(req);
+ nfs_readpage_release(req, error);
}
out:
hdr->release(hdr);
@@ -213,7 +225,7 @@ nfs_async_read_error(struct list_head *head, int error)
while (!list_empty(head)) {
req = nfs_list_entry(head->next);
nfs_list_remove_request(req);
- nfs_readpage_release(req);
+ nfs_readpage_release(req, error);
}
}

@@ -337,8 +349,13 @@ int nfs_readpage(struct file *file, struct page *page)
goto out;
}

+ xchg(&ctx->error, 0);
error = nfs_readpage_async(ctx, inode, page);
-
+ if (!error) {
+ error = wait_on_page_locked_killable(page);
+ if (!PageUptodate(page) && !error)
+ error = xchg(&ctx->error, 0);
+ }
out:
put_nfs_open_context(ctx);
return error;
@@ -372,8 +389,8 @@ readpage_async_filler(void *data, struct page *page)
zero_user_segment(page, len, PAGE_SIZE);
if (!nfs_pageio_add_request(desc->pgio, new)) {
nfs_list_remove_request(new);
- nfs_readpage_release(new);
error = desc->pgio->pg_error;
+ nfs_readpage_release(new, error);
goto out;
}
return 0;
diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index bf3a3f5e1884e..f15dda5efb741 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -599,18 +599,6 @@ static void nfs_write_error(struct nfs_page *req, int error)
nfs_release_request(req);
}

-static bool
-nfs_error_is_fatal_on_server(int err)
-{
- switch (err) {
- case 0:
- case -ERESTARTSYS:
- case -EINTR:
- return false;
- }
- return nfs_error_is_fatal(err);
-}
-
/*
* Find an associated nfs write request, and prepare to flush it out
* May return an error if the user signalled nfs_wait_on_request().
--
2.20.1