From a308996ed7c02d1cd6504ce73436ef3f1c1c75c0 Mon Sep 17 00:00:00 2001
From: Christoph Hellwig <hch@lst.de>
Date: Thu, 11 Jul 2024 09:17:03 +0200
Subject: [PATCH] nfs: split nfs_read_folio
nfs_read_folio is a bit hard to follow because it mixes highlevel logic
with the actual data read. Split the latter into a helper and update
the comments to be more accurate.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
---
fs/nfs/read.c | 69 ++++++++++++++++++++++++++++++---------------------
1 file changed, 41 insertions(+), 28 deletions(-)
diff --git a/fs/nfs/read.c b/fs/nfs/read.c
index 6fee86a2eb420..77fa5458b4bd0 100644
--- a/fs/nfs/read.c
+++ b/fs/nfs/read.c
@@ -325,18 +325,52 @@ int nfs_read_add_folio(struct nfs_pageio_descriptor *pgio,
}
/*
- * Read a page over NFS.
- * We read the page synchronously in the following case:
- * - The error flag is set for this page. This happens only when a
- * previous async read operation failed.
+ * Actually read a folio over the wire.
+ */
+static int nfs_do_read_folio(struct file *file, struct folio *folio)
+{
+ struct inode *inode = file_inode(file);
+ struct nfs_pageio_descriptor pgio;
+ struct nfs_open_context *ctx;
+ int ret;
+
+ ctx = get_nfs_open_context(nfs_file_open_context(file));
+
+ xchg(&ctx->error, 0);
+ nfs_pageio_init_read(&pgio, inode, false,
+ &nfs_async_read_completion_ops);
+
+ ret = nfs_read_add_folio(&pgio, ctx, folio);
+ if (ret)
+ goto out_put;
+
+ nfs_pageio_complete_read(&pgio);
+ nfs_update_delegated_atime(inode);
+ if (pgio.pg_error < 0) {
+ ret = pgio.pg_error;
+ goto out_put;
+ }
+
+ ret = folio_wait_locked_killable(folio);
+ if (!folio_test_uptodate(folio) && !ret)
+ ret = xchg(&ctx->error, 0);
+
+out_put:
+ put_nfs_open_context(ctx);
+ return ret;
+}
+
+/*
+ * Synchronously read a folio.
+ *
+ * This is not heavily used as most users to try an asynchronous
+ * large read through ->readahead first.
*/
int nfs_read_folio(struct file *file, struct folio *folio)
{
struct inode *inode = file_inode(file);
loff_t pos = folio_pos(folio);
size_t len = folio_size(folio);
- struct nfs_pageio_descriptor pgio;
- struct nfs_open_context *ctx;
int ret;
trace_nfs_aop_readpage(inode, pos, len);
@@ -361,29 +395,8 @@ int nfs_read_folio(struct file *file, struct folio *folio)
goto out_unlock;
ret = nfs_netfs_read_folio(file, folio);
- if (!ret)
- goto out;
-
- ctx = get_nfs_open_context(nfs_file_open_context(file));
-
- xchg(&ctx->error, 0);
- nfs_pageio_init_read(&pgio, inode, false,
- &nfs_async_read_completion_ops);
-
- ret = nfs_read_add_folio(&pgio, ctx, folio);
if (ret)
- goto out_put;
-
- nfs_pageio_complete_read(&pgio);
- nfs_update_delegated_atime(inode);
- ret = pgio.pg_error < 0 ? pgio.pg_error : 0;
- if (!ret) {
- ret = folio_wait_locked_killable(folio);
- if (!folio_test_uptodate(folio) && !ret)
- ret = xchg(&ctx->error, 0);
- }
-out_put:
- put_nfs_open_context(ctx);
+ ret = nfs_do_read_folio(file, folio);
out:
trace_nfs_aop_readpage_done(inode, pos, len, ret);
return ret;
--
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