On Thu, 2022-09-22 at 09:58 -0400, Dave Wysochanski wrote:
> Convert the NFS buffered read code paths to corresponding netfs APIs,
> but only when fscache is configured and enabled.
>
> The netfs API defines struct netfs_request_ops which must be filled
> in by the network filesystem. For NFS, we only need to define 5 of
> the functions, the main one being the issue_read() function.
> The issue_read() function is called by the netfs layer when a read
> cannot be fulfilled locally, and must be sent to the server (either
> the cache is not active, or it is active but the data is not available).
> Once the read from the server is complete, netfs requires a call to
> netfs_subreq_terminated() which conveys either how many bytes were read
> successfully, or an error. Note that issue_read() is called with a
> structure, netfs_io_subrequest, which defines the IO requested, and
> contains a start and a length (both in bytes), and assumes the underlying
> netfs will return a either an error on the whole region, or the number
> of bytes successfully read.
>
> The NFS IO path is page based and the main APIs are the pgio APIs defined
> in pagelist.c. For the pgio APIs, there is no way for the caller to
> know how many RPCs will be sent and how the pages will be broken up
> into underlying RPCs, each of which will have their own completion and
> return code. In contrast, netfs is subrequest based, a single
> subrequest may contain multiple pages, and a single subrequest is
> initiated with issue_read() and terminated with netfs_subreq_terminated().
> Thus, to utilze the netfs APIs, NFS needs some way to accommodate
> the netfs API requirement on the single response to the whole
> subrequest, while also minimizing disruptive changes to the NFS
> pgio layer.
>
> The approach taken with this patch is to allocate a small structure
> for each nfs_netfs_issue_read() call, store the final error and number
> of bytes successfully transferred in the structure, and update these values
> as each RPC completes. The refcount on the structure is used as a marker
> for the last RPC completion, is incremented in nfs_netfs_read_initiate(),
> and decremented inside nfs_netfs_read_completion(), when a nfs_pgio_header
> contains a valid pointer to the data. On the final put (which signals
> the final outstanding RPC is complete) in nfs_netfs_read_completion(),
> call netfs_subreq_terminated() with either the final error value (if
> one or more READs complete with an error) or the number of bytes
> successfully transferred (if all RPCs complete successfully). Note
> that when all RPCs complete successfully, the number of bytes transferred
> is capped to the length of the subrequest. Capping the transferred length
> to the subrequest length prevents "Subreq overread" warnings from netfs.
> This is due to the "aligned_len" in nfs_pageio_add_page(), and the
> corner case where NFS requests a full page at the end of the file,
> even when i_size reflects only a partial page (NFS overread).
>
> Suggested-by: Jeff Layton <jlay...@kernel.org>
> Signed-off-by: Dave Wysochanski <dwyso...@redhat.com>
> ---
> fs/nfs/fscache.c | 232 +++++++++++++++++++++++----------------
> fs/nfs/fscache.h | 102 +++++++++++------
> fs/nfs/inode.c | 2 +
> fs/nfs/internal.h | 9 ++
> fs/nfs/pagelist.c | 12 ++
> fs/nfs/read.c | 50 ++++-----
> include/linux/nfs_page.h | 3 +
> include/linux/nfs_xdr.h | 3 +
> 8 files changed, 261 insertions(+), 152 deletions(-)
>
> diff --git a/fs/nfs/fscache.c b/fs/nfs/fscache.c
> index a6fc1c8b6644..58462f6579d6 100644
> --- a/fs/nfs/fscache.c
> +++ b/fs/nfs/fscache.c
> @@ -15,6 +15,9 @@
> #include <linux/seq_file.h>
> #include <linux/slab.h>
> #include <linux/iversion.h>
> +#include <linux/xarray.h>
> +#include <linux/fscache.h>
> +#include <linux/netfs.h>
>
> #include "internal.h"
> #include "iostat.h"
> @@ -184,7 +187,7 @@ void nfs_fscache_init_inode(struct inode *inode)
> */
> void nfs_fscache_clear_inode(struct inode *inode)
> {
> - fscache_relinquish_cookie(netfs_i_cookie(&NFS_I(inode)->netfs), false);
> + fscache_relinquish_cookie(netfs_i_cookie(netfs_inode(inode)), false);
> netfs_inode(inode)->cache = NULL;
> }
>
> @@ -210,7 +213,7 @@ void nfs_fscache_clear_inode(struct inode *inode)
> void nfs_fscache_open_file(struct inode *inode, struct file *filp)
> {
> struct nfs_fscache_inode_auxdata auxdata;
> - struct fscache_cookie *cookie = netfs_i_cookie(&NFS_I(inode)->netfs);
> + struct fscache_cookie *cookie = netfs_i_cookie(netfs_inode(inode));
> bool open_for_write = inode_is_open_for_write(inode);
>
> if (!fscache_cookie_valid(cookie))
> @@ -228,119 +231,160 @@ EXPORT_SYMBOL_GPL(nfs_fscache_open_file);
> void nfs_fscache_release_file(struct inode *inode, struct file *filp)
> {
> struct nfs_fscache_inode_auxdata auxdata;
> - struct fscache_cookie *cookie = netfs_i_cookie(&NFS_I(inode)->netfs);
> + struct fscache_cookie *cookie = netfs_i_cookie(netfs_inode(inode));
> loff_t i_size = i_size_read(inode);
>
> nfs_fscache_update_auxdata(&auxdata, inode);
> fscache_unuse_cookie(cookie, &auxdata, &i_size);
> }
>
> -/*
> - * Fallback page reading interface.
> - */
> -static int fscache_fallback_read_page(struct inode *inode, struct page *page)
> +int nfs_netfs_read_folio(struct file *file, struct folio *folio)
> {
> - struct netfs_cache_resources cres;
> - struct fscache_cookie *cookie = netfs_i_cookie(&NFS_I(inode)->netfs);
> - struct iov_iter iter;
> - struct bio_vec bvec[1];
> - int ret;
> -
> - memset(&cres, 0, sizeof(cres));
> - bvec[0].bv_page = page;
> - bvec[0].bv_offset = 0;
> - bvec[0].bv_len = PAGE_SIZE;
> - iov_iter_bvec(&iter, READ, bvec, ARRAY_SIZE(bvec), PAGE_SIZE);
> -
> - ret = fscache_begin_read_operation(&cres, cookie);
> - if (ret < 0)
> - return ret;
> -
> - ret = fscache_read(&cres, page_offset(page), &iter,
> NETFS_READ_HOLE_FAIL,
> - NULL, NULL);
> - fscache_end_operation(&cres);
> - return ret;
> + if (!netfs_inode(folio_inode(folio))->cache)
> + return -ENOBUFS;
> +
> + return netfs_read_folio(file, folio);
> }
>
> -/*
> - * Fallback page writing interface.
> - */
> -static int fscache_fallback_write_page(struct inode *inode, struct page
> *page,
> - bool no_space_allocated_yet)
> +int nfs_netfs_readahead(struct readahead_control *ractl)
> {
> - struct netfs_cache_resources cres;
> - struct fscache_cookie *cookie = netfs_i_cookie(&NFS_I(inode)->netfs);
> - struct iov_iter iter;
> - struct bio_vec bvec[1];
> - loff_t start = page_offset(page);
> - size_t len = PAGE_SIZE;
> - int ret;
> -
> - memset(&cres, 0, sizeof(cres));
> - bvec[0].bv_page = page;
> - bvec[0].bv_offset = 0;
> - bvec[0].bv_len = PAGE_SIZE;
> - iov_iter_bvec(&iter, WRITE, bvec, ARRAY_SIZE(bvec), PAGE_SIZE);
> -
> - ret = fscache_begin_write_operation(&cres, cookie);
> - if (ret < 0)
> - return ret;
> -
> - ret = cres.ops->prepare_write(&cres, &start, &len, i_size_read(inode),
> - no_space_allocated_yet);
> - if (ret == 0)
> - ret = fscache_write(&cres, page_offset(page), &iter, NULL,
> NULL);
> - fscache_end_operation(&cres);
> - return ret;
> + struct inode *inode = ractl->mapping->host;
> +
> + if (!netfs_inode(inode)->cache)
> + return -ENOBUFS;
> +
> + netfs_readahead(ractl);
> + return 0;
> }
>
> -/*
> - * Retrieve a page from fscache
> - */
> -int __nfs_fscache_read_page(struct inode *inode, struct page *page)
> +atomic_t nfs_netfs_debug_id;
> +static int nfs_netfs_init_request(struct netfs_io_request *rreq, struct file
> *file)
> {
> - int ret;
> + rreq->netfs_priv = get_nfs_open_context(nfs_file_open_context(file));
> + rreq->debug_id = atomic_inc_return(&nfs_netfs_debug_id);
>
> - trace_nfs_fscache_read_page(inode, page);
> - if (PageChecked(page)) {
> - ClearPageChecked(page);
> - ret = 1;
> - goto out;
> - }
> + return 0;
> +}
>
> - ret = fscache_fallback_read_page(inode, page);
> - if (ret < 0) {
> - nfs_inc_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_FAIL);
> - SetPageChecked(page);
> - goto out;
> - }
> +static void nfs_netfs_free_request(struct netfs_io_request *rreq)
> +{
> + put_nfs_open_context(rreq->netfs_priv);
> +}
>
> - /* Read completed synchronously */
> - nfs_inc_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_OK);
> - SetPageUptodate(page);
> - ret = 0;
> -out:
> - trace_nfs_fscache_read_page_exit(inode, page, ret);
> - return ret;
> +static inline int nfs_netfs_begin_cache_operation(struct netfs_io_request
> *rreq)
> +{
> + return fscache_begin_read_operation(&rreq->cache_resources,
> +
> netfs_i_cookie(netfs_inode(rreq->inode)));
> }
>
> -/*
> - * Store a newly fetched page in fscache. We can be certain there's no page
> - * stored in the cache as yet otherwise we would've read it from there.
> - */
> -void __nfs_fscache_write_page(struct inode *inode, struct page *page)
> +static struct nfs_netfs_io_data *nfs_netfs_alloc(struct netfs_io_subrequest
> *sreq)
> {
> - int ret;
> + struct nfs_netfs_io_data *netfs;
> +
> + netfs = kzalloc(sizeof(*netfs), GFP_KERNEL_ACCOUNT);
> + if (!netfs)
> + return NULL;
> + netfs->sreq = sreq;
> + refcount_set(&netfs->refcount, 1);
> + return netfs;
> +}
>
> - trace_nfs_fscache_write_page(inode, page);
> +static bool nfs_netfs_clamp_length(struct netfs_io_subrequest *sreq)
> +{
> + size_t rsize = NFS_SB(sreq->rreq->inode->i_sb)->rsize;
>
> - ret = fscache_fallback_write_page(inode, page, true);
> + sreq->len = min(sreq->len, rsize);
> + return true;
> +}
>
> - if (ret != 0) {
> - nfs_inc_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_WRITTEN_FAIL);
> - nfs_inc_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_UNCACHED);
> - } else {
> - nfs_inc_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_WRITTEN_OK);
> +static void nfs_netfs_issue_read(struct netfs_io_subrequest *sreq)
> +{
> + struct nfs_netfs_io_data *netfs;
> + struct nfs_pageio_descriptor pgio;
> + struct inode *inode = sreq->rreq->inode;
> + struct nfs_open_context *ctx = sreq->rreq->netfs_priv;
> + struct page *page;
> + int err;
> + pgoff_t start = (sreq->start + sreq->transferred) >> PAGE_SHIFT;
> + pgoff_t last = ((sreq->start + sreq->len -
> + sreq->transferred - 1) >> PAGE_SHIFT);
> + XA_STATE(xas, &sreq->rreq->mapping->i_pages, start);
> +
> + nfs_pageio_init_read(&pgio, inode, false,
> + &nfs_async_read_completion_ops);
> +
> + netfs = nfs_netfs_alloc(sreq);
> + if (!netfs)
> + return netfs_subreq_terminated(sreq, -ENOMEM, false);
> +
> + pgio.pg_netfs = netfs; /* used in completion */
> +
> + xas_lock(&xas);
> + xas_for_each(&xas, page, last) {
> + /* nfs_pageio_add_page() may schedule() due to pNFS layout and
> other RPCs */
> + xas_pause(&xas);
> + xas_unlock(&xas);
> + err = nfs_pageio_add_page(&pgio, ctx, page);
> + if (err < 0) {
> + netfs->error = err;
> + goto out;
> + }
> + xas_lock(&xas);
> }
> - trace_nfs_fscache_write_page_exit(inode, page, ret);
> + xas_unlock(&xas);
> +out:
> + nfs_pageio_complete_read(&pgio);
> + nfs_netfs_put(netfs);
> +}
> +
> +void nfs_netfs_initiate_read(struct nfs_pgio_header *hdr)
> +{
> + struct nfs_netfs_io_data *netfs = hdr->netfs;
> +
> + if (!netfs)
> + return;
> +
> + nfs_netfs_get(netfs);
> +}
> +
> +void nfs_netfs_readpage_release(struct nfs_page *req)
> +{
> + struct inode *inode = d_inode(nfs_req_openctx(req)->dentry);
> +
> + /*
> + * If fscache is enabled, netfs will unlock pages.
> + */
> + if (netfs_inode(inode)->cache)
> + return;
> +
> + unlock_page(req->wb_page);
> }
> +
> +void nfs_netfs_read_completion(struct nfs_pgio_header *hdr)
> +{
> + struct nfs_netfs_io_data *netfs = hdr->netfs;
> + struct netfs_io_subrequest *sreq;
> +
> + if (!netfs)
> + return;
> +
> + sreq = netfs->sreq;
> + if (test_bit(NFS_IOHDR_EOF, &hdr->flags))
> + __set_bit(NETFS_SREQ_CLEAR_TAIL, &sreq->flags);
> +
> + if (hdr->error)
> + netfs->error = hdr->error;
> + else
> + atomic64_add(hdr->res.count, &netfs->transferred);
> +
> + nfs_netfs_put(netfs);
> + hdr->netfs = NULL;
> +}
> +
> +const struct netfs_request_ops nfs_netfs_ops = {
> + .init_request = nfs_netfs_init_request,
> + .free_request = nfs_netfs_free_request,
> + .begin_cache_operation = nfs_netfs_begin_cache_operation,
> + .issue_read = nfs_netfs_issue_read,
> + .clamp_length = nfs_netfs_clamp_length
> +};
> diff --git a/fs/nfs/fscache.h b/fs/nfs/fscache.h
> index 38614ed8f951..8d9d916b3a86 100644
> --- a/fs/nfs/fscache.h
> +++ b/fs/nfs/fscache.h
> @@ -34,6 +34,58 @@ struct nfs_fscache_inode_auxdata {
> u64 change_attr;
> };
>
> +struct nfs_netfs_io_data {
> + /*
> + * NFS may split a netfs_io_subrequest into multiple RPCs, each
> + * with their own read completion. In netfs, we can only call
> + * netfs_subreq_terminated() once for each subrequest. Use the
> + * refcount here to double as a marker of the last RPC completion,
> + * and only call netfs via netfs_subreq_terminated() once.
> + */
> + refcount_t refcount;
> + struct netfs_io_subrequest *sreq;
> +
> + /*
> + * Final disposition of the netfs_io_subrequest, sent in
> + * netfs_subreq_terminated()
> + */
> + atomic64_t transferred;
> + int error;
> +};
> +
> +static inline void nfs_netfs_get(struct nfs_netfs_io_data *netfs)
> +{
> + refcount_inc(&netfs->refcount);
> +}
> +
> +static inline void nfs_netfs_put(struct nfs_netfs_io_data *netfs)
> +{
> + ssize_t final_len;
> +
> + /* Only the last RPC completion should call netfs_subreq_terminated() */
> + if (!refcount_dec_and_test(&netfs->refcount))
> + return;
> +
> + /*
> + * The NFS pageio interface may read a complete page, even when netfs
> + * only asked for a partial page. Specifically, this may be seen when
> + * one thread is truncating a file while another one is reading the last
> + * page of the file.
> + * Correct the final length here to be no larger than the netfs
> subrequest
> + * length, and prevent netfs from complain throwing "Subreq overread".
> + */
> + final_len = min_t(s64, netfs->sreq->len,
> atomic64_read(&netfs->transferred));
> + netfs_subreq_terminated(netfs->sreq, netfs->error ?: final_len, false);
> + kfree(netfs);
> +}
> +static inline void nfs_netfs_inode_init(struct nfs_inode *nfsi)
> +{
> + netfs_inode_init(&nfsi->netfs, &nfs_netfs_ops);
> +}
> +extern void nfs_netfs_initiate_read(struct nfs_pgio_header *hdr);
> +extern void nfs_netfs_read_completion(struct nfs_pgio_header *hdr);
> +extern void nfs_netfs_readpage_release(struct nfs_page *req);
> +
> /*
> * fscache.c
> */
> @@ -44,9 +96,8 @@ extern void nfs_fscache_init_inode(struct inode *);
> extern void nfs_fscache_clear_inode(struct inode *);
> extern void nfs_fscache_open_file(struct inode *, struct file *);
> extern void nfs_fscache_release_file(struct inode *, struct file *);
> -
> -extern int __nfs_fscache_read_page(struct inode *, struct page *);
> -extern void __nfs_fscache_write_page(struct inode *, struct page *);
> +extern int nfs_netfs_readahead(struct readahead_control *ractl);
> +extern int nfs_netfs_read_folio(struct file *file, struct folio *folio);
>
> static inline bool nfs_fscache_release_folio(struct folio *folio, gfp_t gfp)
> {
> @@ -54,34 +105,11 @@ static inline bool nfs_fscache_release_folio(struct
> folio *folio, gfp_t gfp)
> if (current_is_kswapd() || !(gfp & __GFP_FS))
> return false;
> folio_wait_fscache(folio);
> -
> fscache_note_page_release(netfs_i_cookie(&NFS_I(folio->mapping->host)->netfs));
> - nfs_inc_fscache_stats(folio->mapping->host,
> - NFSIOS_FSCACHE_PAGES_UNCACHED);
> }
> +
> fscache_note_page_release(netfs_i_cookie(&NFS_I(folio->mapping->host)->netfs));
> return true;
> }
>
> -/*
> - * Retrieve a page from an inode data storage object.
> - */
> -static inline int nfs_fscache_read_page(struct inode *inode, struct page
> *page)
> -{
> - if (netfs_inode(inode)->cache)
> - return __nfs_fscache_read_page(inode, page);
> - return -ENOBUFS;
> -}
> -
> -/*
> - * Store a page newly fetched from the server in an inode data storage object
> - * in the cache.
> - */
> -static inline void nfs_fscache_write_page(struct inode *inode,
> - struct page *page)
> -{
> - if (netfs_inode(inode)->cache)
> - __nfs_fscache_write_page(inode, page);
> -}
> -
> static inline void nfs_fscache_update_auxdata(struct
> nfs_fscache_inode_auxdata *auxdata,
> struct inode *inode)
> {
> @@ -118,6 +146,13 @@ static inline const char
> *nfs_server_fscache_state(struct nfs_server *server)
> }
>
> #else /* CONFIG_NFS_FSCACHE */
> +static inline void nfs_netfs_inode_init(struct nfs_inode *nfsi) {}
> +static inline void nfs_netfs_initiate_read(struct nfs_pgio_header *hdr) {}
> +static inline void nfs_netfs_read_completion(struct nfs_pgio_header *hdr) {}
> +static inline void nfs_netfs_readpage_release(struct nfs_page *req)
> +{
> + unlock_page(req->wb_page);
> +}
> static inline void nfs_fscache_release_super_cookie(struct super_block *sb)
> {}
>
> static inline void nfs_fscache_init_inode(struct inode *inode) {}
> @@ -125,16 +160,19 @@ static inline void nfs_fscache_clear_inode(struct inode
> *inode) {}
> static inline void nfs_fscache_open_file(struct inode *inode,
> struct file *filp) {}
> static inline void nfs_fscache_release_file(struct inode *inode, struct file
> *file) {}
> -
> -static inline bool nfs_fscache_release_folio(struct folio *folio, gfp_t gfp)
> +static inline int nfs_netfs_readahead(struct readahead_control *ractl)
> {
> - return true; /* may release folio */
> + return -ENOBUFS;
> }
> -static inline int nfs_fscache_read_page(struct inode *inode, struct page
> *page)
> +static inline int nfs_netfs_read_folio(struct file *file, struct folio
> *folio)
> {
> return -ENOBUFS;
> }
> -static inline void nfs_fscache_write_page(struct inode *inode, struct page
> *page) {}
> +
> +static inline bool nfs_fscache_release_folio(struct folio *folio, gfp_t gfp)
> +{
> + return true; /* may release folio */
> +}
> static inline void nfs_fscache_invalidate(struct inode *inode, int flags) {}
>
> static inline const char *nfs_server_fscache_state(struct nfs_server *server)
> diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
> index aa2aec785ab5..b36a02b932e8 100644
> --- a/fs/nfs/inode.c
> +++ b/fs/nfs/inode.c
> @@ -2249,6 +2249,8 @@ struct inode *nfs_alloc_inode(struct super_block *sb)
> #ifdef CONFIG_NFS_V4_2
> nfsi->xattr_cache = NULL;
> #endif
> + nfs_netfs_inode_init(nfsi);
> +
> return VFS_I(nfsi);
> }
> EXPORT_SYMBOL_GPL(nfs_alloc_inode);
> diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
> index 4d240ac4430f..e9c0e4abc954 100644
> --- a/fs/nfs/internal.h
> +++ b/fs/nfs/internal.h
> @@ -453,6 +453,10 @@ extern void nfs_sb_deactive(struct super_block *sb);
> extern int nfs_client_for_each_server(struct nfs_client *clp,
> int (*fn)(struct nfs_server *, void *),
> void *data);
> +#ifdef CONFIG_NFS_FSCACHE
> +extern const struct netfs_request_ops nfs_netfs_ops;
> +#endif
> +
> /* io.c */
> extern void nfs_start_io_read(struct inode *inode);
> extern void nfs_end_io_read(struct inode *inode);
> @@ -482,9 +486,14 @@ extern int nfs4_get_rootfh(struct nfs_server *server,
> struct nfs_fh *mntfh, bool
>
> struct nfs_pgio_completion_ops;
> /* read.c */
> +extern const struct nfs_pgio_completion_ops nfs_async_read_completion_ops;
> extern void nfs_pageio_init_read(struct nfs_pageio_descriptor *pgio,
> struct inode *inode, bool force_mds,
> const struct nfs_pgio_completion_ops *compl_ops);
> +extern int nfs_pageio_add_page(struct nfs_pageio_descriptor *pgio,
> + struct nfs_open_context *ctx,
> + struct page *page);
> +extern void nfs_pageio_complete_read(struct nfs_pageio_descriptor *pgio);
> extern void nfs_read_prepare(struct rpc_task *task, void *calldata);
> extern void nfs_pageio_reset_read_mds(struct nfs_pageio_descriptor *pgio);
>
> diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c
> index 317cedfa52bf..e28754476d1b 100644
> --- a/fs/nfs/pagelist.c
> +++ b/fs/nfs/pagelist.c
> @@ -25,6 +25,7 @@
> #include "internal.h"
> #include "pnfs.h"
> #include "nfstrace.h"
> +#include "fscache.h"
>
> #define NFSDBG_FACILITY NFSDBG_PAGECACHE
>
> @@ -68,6 +69,10 @@ void nfs_pgheader_init(struct nfs_pageio_descriptor *desc,
> hdr->good_bytes = mirror->pg_count;
> hdr->io_completion = desc->pg_io_completion;
> hdr->dreq = desc->pg_dreq;
> +#ifdef CONFIG_NFS_FSCACHE
> + if (desc->pg_netfs)
> + hdr->netfs = desc->pg_netfs;
> +#endif
> hdr->release = release;
> hdr->completion_ops = desc->pg_completion_ops;
> if (hdr->completion_ops->init_hdr)
> @@ -846,6 +851,9 @@ void nfs_pageio_init(struct nfs_pageio_descriptor *desc,
> desc->pg_lseg = NULL;
> desc->pg_io_completion = NULL;
> desc->pg_dreq = NULL;
> +#ifdef CONFIG_NFS_FSCACHE
> + desc->pg_netfs = NULL;
> +#endif
> desc->pg_bsize = bsize;
>
> desc->pg_mirror_count = 1;
> @@ -940,6 +948,7 @@ int nfs_generic_pgio(struct nfs_pageio_descriptor *desc,
> /* Set up the argument struct */
> nfs_pgio_rpcsetup(hdr, mirror->pg_count, desc->pg_ioflags, &cinfo);
> desc->pg_rpc_callops = &nfs_pgio_common_ops;
> +
> return 0;
> }
> EXPORT_SYMBOL_GPL(nfs_generic_pgio);
> @@ -1360,6 +1369,9 @@ int nfs_pageio_resend(struct nfs_pageio_descriptor
> *desc,
>
> desc->pg_io_completion = hdr->io_completion;
> desc->pg_dreq = hdr->dreq;
> +#ifdef CONFIG_NFS_FSCACHE
> + desc->pg_netfs = hdr->netfs;
> +#endif
> list_splice_init(&hdr->pages, &pages);
> while (!list_empty(&pages)) {
> struct nfs_page *req = nfs_list_entry(pages.next);
> diff --git a/fs/nfs/read.c b/fs/nfs/read.c
> index 525e82ea9a9e..fdfebca017fc 100644
> --- a/fs/nfs/read.c
> +++ b/fs/nfs/read.c
> @@ -30,7 +30,7 @@
>
> #define NFSDBG_FACILITY NFSDBG_PAGECACHE
>
> -static const struct nfs_pgio_completion_ops nfs_async_read_completion_ops;
> +const struct nfs_pgio_completion_ops nfs_async_read_completion_ops;
> static const struct nfs_rw_ops nfs_rw_read_ops;
>
> static struct kmem_cache *nfs_rdata_cachep;
> @@ -74,7 +74,7 @@ void nfs_pageio_init_read(struct nfs_pageio_descriptor
> *pgio,
> }
> EXPORT_SYMBOL_GPL(nfs_pageio_init_read);
>
> -static void nfs_pageio_complete_read(struct nfs_pageio_descriptor *pgio)
> +void nfs_pageio_complete_read(struct nfs_pageio_descriptor *pgio)
> {
> struct nfs_pgio_mirror *pgm;
> unsigned long npages;
> @@ -110,20 +110,13 @@ EXPORT_SYMBOL_GPL(nfs_pageio_reset_read_mds);
>
> 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(page))
> - nfs_fscache_write_page(inode, page);
> - unlock_page(page);
> - }
> + if (nfs_page_group_sync_on_bit(req, PG_UNLOCKPAGE))
> + nfs_netfs_readpage_release(req);
> +
> nfs_release_request(req);
> }
>
> @@ -177,6 +170,8 @@ static void nfs_read_completion(struct nfs_pgio_header
> *hdr)
> nfs_list_remove_request(req);
> nfs_readpage_release(req, error);
> }
> + nfs_netfs_read_completion(hdr);
> +
> out:
> hdr->release(hdr);
> }
> @@ -187,6 +182,7 @@ static void nfs_initiate_read(struct nfs_pgio_header *hdr,
> struct rpc_task_setup *task_setup_data, int how)
> {
> rpc_ops->read_setup(hdr, msg);
> + nfs_netfs_initiate_read(hdr);
> trace_nfs_initiate_read(hdr);
> }
>
> @@ -202,7 +198,7 @@ nfs_async_read_error(struct list_head *head, int error)
> }
> }
>
> -static const struct nfs_pgio_completion_ops nfs_async_read_completion_ops = {
> +const struct nfs_pgio_completion_ops nfs_async_read_completion_ops = {
> .error_cleanup = nfs_async_read_error,
> .completion = nfs_read_completion,
> };
> @@ -294,12 +290,6 @@ nfs_pageio_add_page(struct nfs_pageio_descriptor *pgio,
>
> aligned_len = min_t(unsigned int, ALIGN(len, rsize), PAGE_SIZE);
>
> - if (!IS_SYNC(page->mapping->host)) {
> - error = nfs_fscache_read_page(page->mapping->host, page);
> - if (error == 0)
> - goto out_unlock;
> - }
> -
> new = nfs_create_request(ctx, page, 0, aligned_len);
> if (IS_ERR(new))
> goto out_error;
> @@ -315,8 +305,6 @@ nfs_pageio_add_page(struct nfs_pageio_descriptor *pgio,
> return 0;
> out_error:
> error = PTR_ERR(new);
> -out_unlock:
> - unlock_page(page);
> out:
> return error;
> }
> @@ -355,6 +343,10 @@ int nfs_read_folio(struct file *file, struct folio
> *folio)
> if (NFS_STALE(inode))
> goto out_unlock;
>
> + ret = nfs_netfs_read_folio(file, folio);
> + if (!ret)
> + goto out;
> +
> if (file == NULL) {
> ret = -EBADF;
> ctx = nfs_find_open_context(inode, NULL, FMODE_READ);
> @@ -368,8 +360,10 @@ int nfs_read_folio(struct file *file, struct folio
> *folio)
> &nfs_async_read_completion_ops);
>
> ret = nfs_pageio_add_page(&pgio, ctx, page);
> - if (ret)
> - goto out;
> + if (ret) {
> + put_nfs_open_context(ctx);
> + goto out_unlock;
> + }
>
> nfs_pageio_complete_read(&pgio);
> ret = pgio.pg_error < 0 ? pgio.pg_error : 0;
> @@ -378,12 +372,12 @@ int nfs_read_folio(struct file *file, struct folio
> *folio)
> if (!PageUptodate(page) && !ret)
> ret = xchg(&ctx->error, 0);
> }
> -out:
> put_nfs_open_context(ctx);
> - trace_nfs_aop_readpage_done(inode, page, ret);
> - return ret;
> + goto out;
> +
> out_unlock:
> unlock_page(page);
> +out:
> trace_nfs_aop_readpage_done(inode, page, ret);
> return ret;
> }
> @@ -405,6 +399,10 @@ void nfs_readahead(struct readahead_control *ractl)
> if (NFS_STALE(inode))
> goto out;
>
> + ret = nfs_netfs_readahead(ractl);
> + if (!ret)
> + goto out;
> +
> if (file == NULL) {
> ret = -EBADF;
> ctx = nfs_find_open_context(inode, NULL, FMODE_READ);
> diff --git a/include/linux/nfs_page.h b/include/linux/nfs_page.h
> index ba7e2e4b0926..8eeb16d9bacd 100644
> --- a/include/linux/nfs_page.h
> +++ b/include/linux/nfs_page.h
> @@ -101,6 +101,9 @@ struct nfs_pageio_descriptor {
> struct pnfs_layout_segment *pg_lseg;
> struct nfs_io_completion *pg_io_completion;
> struct nfs_direct_req *pg_dreq;
> +#ifdef CONFIG_NFS_FSCACHE
> + void *pg_netfs;
> +#endif
> unsigned int pg_bsize; /* default bsize for mirrors */
>
> u32 pg_mirror_count;
> diff --git a/include/linux/nfs_xdr.h b/include/linux/nfs_xdr.h
> index e86cf6642d21..e196ef595908 100644
> --- a/include/linux/nfs_xdr.h
> +++ b/include/linux/nfs_xdr.h
> @@ -1619,6 +1619,9 @@ struct nfs_pgio_header {
> const struct nfs_rw_ops *rw_ops;
> struct nfs_io_completion *io_completion;
> struct nfs_direct_req *dreq;
> +#ifdef CONFIG_NFS_FSCACHE
> + void *netfs;
> +#endif
>
> int pnfs_error;
> int error; /* merge with pnfs_error */
Reviewed-by: Jeff Layton <jlay...@kernel.org>
--
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