]> git.ipfire.org Git - thirdparty/linux.git/commitdiff
netfs: Add support for caching single monolithic objects such as AFS dirs
authorDavid Howells <dhowells@redhat.com>
Mon, 16 Dec 2024 20:41:09 +0000 (20:41 +0000)
committerChristian Brauner <brauner@kernel.org>
Fri, 20 Dec 2024 21:34:06 +0000 (22:34 +0100)
Add support for caching the content of a file that contains a single
monolithic object that must be read/written with a single I/O operation,
such as an AFS directory.

Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://lore.kernel.org/r/20241216204124.3752367-20-dhowells@redhat.com
cc: Jeff Layton <jlayton@kernel.org>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: netfs@lists.linux.dev
cc: linux-afs@lists.infradead.org
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
12 files changed:
fs/netfs/Makefile
fs/netfs/buffered_read.c
fs/netfs/internal.h
fs/netfs/main.c
fs/netfs/objects.c
fs/netfs/read_collect.c
fs/netfs/read_single.c [new file with mode: 0644]
fs/netfs/stats.c
fs/netfs/write_collect.c
fs/netfs/write_issue.c
include/linux/netfs.h
include/trace/events/netfs.h

index cbb30bdeacc4e51a76714043233e03fadfa08927..b43188d64bd87e28e3469fe753e8c8be60683d34 100644 (file)
@@ -13,6 +13,7 @@ netfs-y := \
        read_collect.o \
        read_pgpriv2.o \
        read_retry.o \
+       read_single.o \
        rolling_buffer.o \
        write_collect.o \
        write_issue.o \
index 4ff4b587dc4b7d2b5a35d24ccc587fa66e4233a4..c420e9dee0e48dcbc52f4f067300aaedf143a9c4 100644 (file)
@@ -137,14 +137,17 @@ static enum netfs_io_source netfs_cache_prepare_read(struct netfs_io_request *rr
                                                     loff_t i_size)
 {
        struct netfs_cache_resources *cres = &rreq->cache_resources;
+       enum netfs_io_source source;
 
        if (!cres->ops)
                return NETFS_DOWNLOAD_FROM_SERVER;
-       return cres->ops->prepare_read(subreq, i_size);
+       source = cres->ops->prepare_read(subreq, i_size);
+       trace_netfs_sreq(subreq, netfs_sreq_trace_prepare);
+       return source;
+
 }
 
-static void netfs_cache_read_terminated(void *priv, ssize_t transferred_or_error,
-                                       bool was_async)
+void netfs_cache_read_terminated(void *priv, ssize_t transferred_or_error, bool was_async)
 {
        struct netfs_io_subrequest *subreq = priv;
 
@@ -213,6 +216,8 @@ static void netfs_read_to_pagecache(struct netfs_io_request *rreq)
                        unsigned long long zp = umin(ictx->zero_point, rreq->i_size);
                        size_t len = subreq->len;
 
+                       if (unlikely(rreq->origin == NETFS_READ_SINGLE))
+                               zp = rreq->i_size;
                        if (subreq->start >= zp) {
                                subreq->source = source = NETFS_FILL_WITH_ZEROES;
                                goto fill_with_zeroes;
index ba32ca61063c0eceab40dfd891a560200a4d1aca..e236f752af88123ef10b820d478389cf155023b5 100644 (file)
@@ -23,6 +23,7 @@
 /*
  * buffered_read.c
  */
+void netfs_cache_read_terminated(void *priv, ssize_t transferred_or_error, bool was_async);
 int netfs_prefetch_for_write(struct file *file, struct folio *folio,
                             size_t offset, size_t len);
 
@@ -110,6 +111,7 @@ void netfs_unlock_abandoned_read_pages(struct netfs_io_request *rreq);
 extern atomic_t netfs_n_rh_dio_read;
 extern atomic_t netfs_n_rh_readahead;
 extern atomic_t netfs_n_rh_read_folio;
+extern atomic_t netfs_n_rh_read_single;
 extern atomic_t netfs_n_rh_rreq;
 extern atomic_t netfs_n_rh_sreq;
 extern atomic_t netfs_n_rh_download;
index 6c7be1377ee0edd9e7b2855dea6ca0d4bf893a1a..8c1922c0cb42f8c0c6bcd67b26fcef0bace7368c 100644 (file)
@@ -37,9 +37,11 @@ static const char *netfs_origins[nr__netfs_io_origin] = {
        [NETFS_READAHEAD]               = "RA",
        [NETFS_READPAGE]                = "RP",
        [NETFS_READ_GAPS]               = "RG",
+       [NETFS_READ_SINGLE]             = "R1",
        [NETFS_READ_FOR_WRITE]          = "RW",
        [NETFS_DIO_READ]                = "DR",
        [NETFS_WRITEBACK]               = "WB",
+       [NETFS_WRITEBACK_SINGLE]        = "W1",
        [NETFS_WRITETHROUGH]            = "WT",
        [NETFS_UNBUFFERED_WRITE]        = "UW",
        [NETFS_DIO_WRITE]               = "DW",
index 8c98b70eb3a4f5e38c7c4ec3fd7976446908e878..dde4a679d9e21c1dc2fa9c46abda5ae05de86ecb 100644 (file)
@@ -54,6 +54,7 @@ struct netfs_io_request *netfs_alloc_request(struct address_space *mapping,
        if (origin == NETFS_READAHEAD ||
            origin == NETFS_READPAGE ||
            origin == NETFS_READ_GAPS ||
+           origin == NETFS_READ_SINGLE ||
            origin == NETFS_READ_FOR_WRITE ||
            origin == NETFS_DIO_READ)
                INIT_WORK(&rreq->work, NULL);
@@ -196,6 +197,7 @@ struct netfs_io_subrequest *netfs_alloc_subrequest(struct netfs_io_request *rreq
        case NETFS_READAHEAD:
        case NETFS_READPAGE:
        case NETFS_READ_GAPS:
+       case NETFS_READ_SINGLE:
        case NETFS_READ_FOR_WRITE:
        case NETFS_DIO_READ:
                INIT_WORK(&subreq->work, netfs_read_subreq_termination_worker);
index 26e430baeb5ad80a4e638a321b6e7bfd82db6fee..2e9291ab1d62de582aeb7c39476f9e12833b6aba 100644 (file)
@@ -361,6 +361,39 @@ static void netfs_rreq_assess_dio(struct netfs_io_request *rreq)
                inode_dio_end(rreq->inode);
 }
 
+/*
+ * Do processing after reading a monolithic single object.
+ */
+static void netfs_rreq_assess_single(struct netfs_io_request *rreq)
+{
+       struct netfs_io_subrequest *subreq;
+       struct netfs_io_stream *stream = &rreq->io_streams[0];
+
+       subreq = list_first_entry_or_null(&stream->subrequests,
+                                         struct netfs_io_subrequest, rreq_link);
+       if (subreq) {
+               if (test_bit(NETFS_SREQ_FAILED, &subreq->flags))
+                       rreq->error = subreq->error;
+               else
+                       rreq->transferred = subreq->transferred;
+
+               if (!rreq->error && subreq->source == NETFS_DOWNLOAD_FROM_SERVER &&
+                   fscache_resources_valid(&rreq->cache_resources)) {
+                       trace_netfs_rreq(rreq, netfs_rreq_trace_dirty);
+                       netfs_single_mark_inode_dirty(rreq->inode);
+               }
+       }
+
+       if (rreq->iocb) {
+               rreq->iocb->ki_pos += rreq->transferred;
+               if (rreq->iocb->ki_complete)
+                       rreq->iocb->ki_complete(
+                               rreq->iocb, rreq->error ? rreq->error : rreq->transferred);
+       }
+       if (rreq->netfs_ops->done)
+               rreq->netfs_ops->done(rreq);
+}
+
 /*
  * Assess the state of a read request and decide what to do next.
  *
@@ -378,9 +411,17 @@ void netfs_rreq_terminated(struct netfs_io_request *rreq)
                return;
        }
 
-       if (rreq->origin == NETFS_DIO_READ ||
-           rreq->origin == NETFS_READ_GAPS)
+       switch (rreq->origin) {
+       case NETFS_DIO_READ:
+       case NETFS_READ_GAPS:
                netfs_rreq_assess_dio(rreq);
+               break;
+       case NETFS_READ_SINGLE:
+               netfs_rreq_assess_single(rreq);
+               break;
+       default:
+               break;
+       }
        task_io_account_read(rreq->transferred);
 
        trace_netfs_rreq(rreq, netfs_rreq_trace_wake_ip);
diff --git a/fs/netfs/read_single.c b/fs/netfs/read_single.c
new file mode 100644 (file)
index 0000000..2a66c5f
--- /dev/null
@@ -0,0 +1,202 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* Single, monolithic object support (e.g. AFS directory).
+ *
+ * Copyright (C) 2024 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#include <linux/export.h>
+#include <linux/fs.h>
+#include <linux/mm.h>
+#include <linux/pagemap.h>
+#include <linux/slab.h>
+#include <linux/uio.h>
+#include <linux/sched/mm.h>
+#include <linux/task_io_accounting_ops.h>
+#include <linux/netfs.h>
+#include "internal.h"
+
+/**
+ * netfs_single_mark_inode_dirty - Mark a single, monolithic object inode dirty
+ * @inode: The inode to mark
+ *
+ * Mark an inode that contains a single, monolithic object as dirty so that its
+ * writepages op will get called.  If set, the SINGLE_NO_UPLOAD flag indicates
+ * that the object will only be written to the cache and not uploaded (e.g. AFS
+ * directory contents).
+ */
+void netfs_single_mark_inode_dirty(struct inode *inode)
+{
+       struct netfs_inode *ictx = netfs_inode(inode);
+       bool cache_only = test_bit(NETFS_ICTX_SINGLE_NO_UPLOAD, &ictx->flags);
+       bool caching = fscache_cookie_enabled(netfs_i_cookie(netfs_inode(inode)));
+
+       if (cache_only && !caching)
+               return;
+
+       mark_inode_dirty(inode);
+
+       if (caching && !(inode->i_state & I_PINNING_NETFS_WB)) {
+               bool need_use = false;
+
+               spin_lock(&inode->i_lock);
+               if (!(inode->i_state & I_PINNING_NETFS_WB)) {
+                       inode->i_state |= I_PINNING_NETFS_WB;
+                       need_use = true;
+               }
+               spin_unlock(&inode->i_lock);
+
+               if (need_use)
+                       fscache_use_cookie(netfs_i_cookie(ictx), true);
+       }
+
+}
+EXPORT_SYMBOL(netfs_single_mark_inode_dirty);
+
+static int netfs_single_begin_cache_read(struct netfs_io_request *rreq, struct netfs_inode *ctx)
+{
+       return fscache_begin_read_operation(&rreq->cache_resources, netfs_i_cookie(ctx));
+}
+
+static void netfs_single_cache_prepare_read(struct netfs_io_request *rreq,
+                                           struct netfs_io_subrequest *subreq)
+{
+       struct netfs_cache_resources *cres = &rreq->cache_resources;
+
+       if (!cres->ops) {
+               subreq->source = NETFS_DOWNLOAD_FROM_SERVER;
+               return;
+       }
+       subreq->source = cres->ops->prepare_read(subreq, rreq->i_size);
+       trace_netfs_sreq(subreq, netfs_sreq_trace_prepare);
+
+}
+
+static void netfs_single_read_cache(struct netfs_io_request *rreq,
+                                   struct netfs_io_subrequest *subreq)
+{
+       struct netfs_cache_resources *cres = &rreq->cache_resources;
+
+       netfs_stat(&netfs_n_rh_read);
+       cres->ops->read(cres, subreq->start, &subreq->io_iter, NETFS_READ_HOLE_FAIL,
+                       netfs_cache_read_terminated, subreq);
+}
+
+/*
+ * Perform a read to a buffer from the cache or the server.  Only a single
+ * subreq is permitted as the object must be fetched in a single transaction.
+ */
+static int netfs_single_dispatch_read(struct netfs_io_request *rreq)
+{
+       struct netfs_io_subrequest *subreq;
+       int ret = 0;
+
+       atomic_set(&rreq->nr_outstanding, 1);
+
+       subreq = netfs_alloc_subrequest(rreq);
+       if (!subreq) {
+               ret = -ENOMEM;
+               goto out;
+       }
+
+       subreq->source  = NETFS_DOWNLOAD_FROM_SERVER;
+       subreq->start   = 0;
+       subreq->len     = rreq->len;
+       subreq->io_iter = rreq->buffer.iter;
+
+       atomic_inc(&rreq->nr_outstanding);
+
+       spin_lock_bh(&rreq->lock);
+       list_add_tail(&subreq->rreq_link, &rreq->subrequests);
+       trace_netfs_sreq(subreq, netfs_sreq_trace_added);
+       spin_unlock_bh(&rreq->lock);
+
+       netfs_single_cache_prepare_read(rreq, subreq);
+       switch (subreq->source) {
+       case NETFS_DOWNLOAD_FROM_SERVER:
+               netfs_stat(&netfs_n_rh_download);
+               if (rreq->netfs_ops->prepare_read) {
+                       ret = rreq->netfs_ops->prepare_read(subreq);
+                       if (ret < 0)
+                               goto cancel;
+               }
+
+               rreq->netfs_ops->issue_read(subreq);
+               rreq->submitted += subreq->len;
+               break;
+       case NETFS_READ_FROM_CACHE:
+               trace_netfs_sreq(subreq, netfs_sreq_trace_submit);
+               netfs_single_read_cache(rreq, subreq);
+               rreq->submitted += subreq->len;
+               ret = 0;
+               break;
+       default:
+               pr_warn("Unexpected single-read source %u\n", subreq->source);
+               WARN_ON_ONCE(true);
+               ret = -EIO;
+               break;
+       }
+
+out:
+       if (atomic_dec_and_test(&rreq->nr_outstanding))
+               netfs_rreq_terminated(rreq);
+       return ret;
+cancel:
+       atomic_dec(&rreq->nr_outstanding);
+       netfs_put_subrequest(subreq, false, netfs_sreq_trace_put_cancel);
+       goto out;
+}
+
+/**
+ * netfs_read_single - Synchronously read a single blob of pages.
+ * @inode: The inode to read from.
+ * @file: The file we're using to read or NULL.
+ * @iter: The buffer we're reading into.
+ *
+ * Fulfil a read request for a single monolithic object by drawing data from
+ * the cache if possible, or the netfs if not.  The buffer may be larger than
+ * the file content; unused beyond the EOF will be zero-filled.  The content
+ * will be read with a single I/O request (though this may be retried).
+ *
+ * The calling netfs must initialise a netfs context contiguous to the vfs
+ * inode before calling this.
+ *
+ * This is usable whether or not caching is enabled.  If caching is enabled,
+ * the data will be stored as a single object into the cache.
+ */
+ssize_t netfs_read_single(struct inode *inode, struct file *file, struct iov_iter *iter)
+{
+       struct netfs_io_request *rreq;
+       struct netfs_inode *ictx = netfs_inode(inode);
+       ssize_t ret;
+
+       rreq = netfs_alloc_request(inode->i_mapping, file, 0, iov_iter_count(iter),
+                                  NETFS_READ_SINGLE);
+       if (IS_ERR(rreq))
+               return PTR_ERR(rreq);
+
+       ret = netfs_single_begin_cache_read(rreq, ictx);
+       if (ret == -ENOMEM || ret == -EINTR || ret == -ERESTARTSYS)
+               goto cleanup_free;
+
+       netfs_stat(&netfs_n_rh_read_single);
+       trace_netfs_read(rreq, 0, rreq->len, netfs_read_trace_read_single);
+
+       rreq->buffer.iter = *iter;
+       netfs_single_dispatch_read(rreq);
+
+       trace_netfs_rreq(rreq, netfs_rreq_trace_wait_ip);
+       wait_on_bit(&rreq->flags, NETFS_RREQ_IN_PROGRESS,
+                   TASK_UNINTERRUPTIBLE);
+
+       ret = rreq->error;
+       if (ret == 0)
+               ret = rreq->transferred;
+       netfs_put_request(rreq, true, netfs_rreq_trace_put_return);
+       return ret;
+
+cleanup_free:
+       netfs_put_request(rreq, false, netfs_rreq_trace_put_failed);
+       return ret;
+}
+EXPORT_SYMBOL(netfs_read_single);
index 8e63516b40f6a4b4d0f6a479ddf09aeb28ddce61..f1af344266cc6aa58c5fcf7ff0f6ffe8b751f4ff 100644 (file)
@@ -12,6 +12,7 @@
 atomic_t netfs_n_rh_dio_read;
 atomic_t netfs_n_rh_readahead;
 atomic_t netfs_n_rh_read_folio;
+atomic_t netfs_n_rh_read_single;
 atomic_t netfs_n_rh_rreq;
 atomic_t netfs_n_rh_sreq;
 atomic_t netfs_n_rh_download;
@@ -46,10 +47,11 @@ atomic_t netfs_n_folioq;
 
 int netfs_stats_show(struct seq_file *m, void *v)
 {
-       seq_printf(m, "Reads  : DR=%u RA=%u RF=%u WB=%u WBZ=%u\n",
+       seq_printf(m, "Reads  : DR=%u RA=%u RF=%u RS=%u WB=%u WBZ=%u\n",
                   atomic_read(&netfs_n_rh_dio_read),
                   atomic_read(&netfs_n_rh_readahead),
                   atomic_read(&netfs_n_rh_read_folio),
+                  atomic_read(&netfs_n_rh_read_single),
                   atomic_read(&netfs_n_rh_write_begin),
                   atomic_read(&netfs_n_rh_write_zskip));
        seq_printf(m, "Writes : BW=%u WT=%u DW=%u WP=%u 2C=%u\n",
index f026cbc0e2fe1c4e8beb74c822dd0f981722b6e0..d54526d2e751ca13c87ecc4154e6f0b877296af6 100644 (file)
@@ -17,7 +17,7 @@
 #define HIT_PENDING            0x01    /* A front op was still pending */
 #define NEED_REASSESS          0x02    /* Need to loop round and reassess */
 #define MADE_PROGRESS          0x04    /* Made progress cleaning up a stream or the folio set */
-#define BUFFERED               0x08    /* The pagecache needs cleaning up */
+#define NEED_UNLOCK            0x08    /* The pagecache needs unlocking */
 #define NEED_RETRY             0x10    /* A front op requests retrying */
 #define SAW_FAILURE            0x20    /* One stream or hit a permanent failure */
 
@@ -179,7 +179,7 @@ reassess_streams:
        if (wreq->origin == NETFS_WRITEBACK ||
            wreq->origin == NETFS_WRITETHROUGH ||
            wreq->origin == NETFS_PGPRIV2_COPY_TO_CACHE)
-               notes = BUFFERED;
+               notes = NEED_UNLOCK;
        else
                notes = 0;
 
@@ -276,7 +276,7 @@ reassess_streams:
        trace_netfs_collect_state(wreq, wreq->collected_to, notes);
 
        /* Unlock any folios that we have now finished with. */
-       if (notes & BUFFERED) {
+       if (notes & NEED_UNLOCK) {
                if (wreq->cleaned_to < wreq->collected_to)
                        netfs_writeback_unlock_folios(wreq, &notes);
        } else {
index 286bc2aa3ca0bd3b37fb8661da61156a957e5cbd..6f14a7c2f0409ab40eab2ddee0dfa662c76bd05c 100644 (file)
@@ -94,9 +94,10 @@ struct netfs_io_request *netfs_create_write_req(struct address_space *mapping,
 {
        struct netfs_io_request *wreq;
        struct netfs_inode *ictx;
-       bool is_buffered = (origin == NETFS_WRITEBACK ||
-                           origin == NETFS_WRITETHROUGH ||
-                           origin == NETFS_PGPRIV2_COPY_TO_CACHE);
+       bool is_cacheable = (origin == NETFS_WRITEBACK ||
+                            origin == NETFS_WRITEBACK_SINGLE ||
+                            origin == NETFS_WRITETHROUGH ||
+                            origin == NETFS_PGPRIV2_COPY_TO_CACHE);
 
        wreq = netfs_alloc_request(mapping, file, start, 0, origin);
        if (IS_ERR(wreq))
@@ -105,7 +106,7 @@ struct netfs_io_request *netfs_create_write_req(struct address_space *mapping,
        _enter("R=%x", wreq->debug_id);
 
        ictx = netfs_inode(wreq->inode);
-       if (is_buffered && netfs_is_cache_enabled(ictx))
+       if (is_cacheable && netfs_is_cache_enabled(ictx))
                fscache_begin_write_operation(&wreq->cache_resources, netfs_i_cookie(ictx));
        if (rolling_buffer_init(&wreq->buffer, wreq->debug_id, ITER_SOURCE) < 0)
                goto nomem;
@@ -452,7 +453,8 @@ static int netfs_write_folio(struct netfs_io_request *wreq,
                stream = &wreq->io_streams[s];
                stream->submit_off = foff;
                stream->submit_len = flen;
-               if ((stream->source == NETFS_WRITE_TO_CACHE && streamw) ||
+               if (!stream->avail ||
+                   (stream->source == NETFS_WRITE_TO_CACHE && streamw) ||
                    (stream->source == NETFS_UPLOAD_TO_SERVER &&
                     fgroup == NETFS_FOLIO_COPY_TO_CACHE)) {
                        stream->submit_off = UINT_MAX;
@@ -731,3 +733,194 @@ int netfs_unbuffered_write(struct netfs_io_request *wreq, bool may_wait, size_t
        _leave(" = %d", error);
        return error;
 }
+
+/*
+ * Write some of a pending folio data back to the server and/or the cache.
+ */
+static int netfs_write_folio_single(struct netfs_io_request *wreq,
+                                   struct folio *folio)
+{
+       struct netfs_io_stream *upload = &wreq->io_streams[0];
+       struct netfs_io_stream *cache  = &wreq->io_streams[1];
+       struct netfs_io_stream *stream;
+       size_t iter_off = 0;
+       size_t fsize = folio_size(folio), flen;
+       loff_t fpos = folio_pos(folio);
+       bool to_eof = false;
+       bool no_debug = false;
+
+       _enter("");
+
+       flen = folio_size(folio);
+       if (flen > wreq->i_size - fpos) {
+               flen = wreq->i_size - fpos;
+               folio_zero_segment(folio, flen, fsize);
+               to_eof = true;
+       } else if (flen == wreq->i_size - fpos) {
+               to_eof = true;
+       }
+
+       _debug("folio %zx/%zx", flen, fsize);
+
+       if (!upload->avail && !cache->avail) {
+               trace_netfs_folio(folio, netfs_folio_trace_cancel_store);
+               return 0;
+       }
+
+       if (!upload->construct)
+               trace_netfs_folio(folio, netfs_folio_trace_store);
+       else
+               trace_netfs_folio(folio, netfs_folio_trace_store_plus);
+
+       /* Attach the folio to the rolling buffer. */
+       folio_get(folio);
+       rolling_buffer_append(&wreq->buffer, folio, NETFS_ROLLBUF_PUT_MARK);
+
+       /* Move the submission point forward to allow for write-streaming data
+        * not starting at the front of the page.  We don't do write-streaming
+        * with the cache as the cache requires DIO alignment.
+        *
+        * Also skip uploading for data that's been read and just needs copying
+        * to the cache.
+        */
+       for (int s = 0; s < NR_IO_STREAMS; s++) {
+               stream = &wreq->io_streams[s];
+               stream->submit_off = 0;
+               stream->submit_len = flen;
+               if (!stream->avail) {
+                       stream->submit_off = UINT_MAX;
+                       stream->submit_len = 0;
+               }
+       }
+
+       /* Attach the folio to one or more subrequests.  For a big folio, we
+        * could end up with thousands of subrequests if the wsize is small -
+        * but we might need to wait during the creation of subrequests for
+        * network resources (eg. SMB credits).
+        */
+       for (;;) {
+               ssize_t part;
+               size_t lowest_off = ULONG_MAX;
+               int choose_s = -1;
+
+               /* Always add to the lowest-submitted stream first. */
+               for (int s = 0; s < NR_IO_STREAMS; s++) {
+                       stream = &wreq->io_streams[s];
+                       if (stream->submit_len > 0 &&
+                           stream->submit_off < lowest_off) {
+                               lowest_off = stream->submit_off;
+                               choose_s = s;
+                       }
+               }
+
+               if (choose_s < 0)
+                       break;
+               stream = &wreq->io_streams[choose_s];
+
+               /* Advance the iterator(s). */
+               if (stream->submit_off > iter_off) {
+                       rolling_buffer_advance(&wreq->buffer, stream->submit_off - iter_off);
+                       iter_off = stream->submit_off;
+               }
+
+               atomic64_set(&wreq->issued_to, fpos + stream->submit_off);
+               stream->submit_extendable_to = fsize - stream->submit_off;
+               part = netfs_advance_write(wreq, stream, fpos + stream->submit_off,
+                                          stream->submit_len, to_eof);
+               stream->submit_off += part;
+               if (part > stream->submit_len)
+                       stream->submit_len = 0;
+               else
+                       stream->submit_len -= part;
+               if (part > 0)
+                       no_debug = true;
+       }
+
+       wreq->buffer.iter.iov_offset = 0;
+       if (fsize > iter_off)
+               rolling_buffer_advance(&wreq->buffer, fsize - iter_off);
+       atomic64_set(&wreq->issued_to, fpos + fsize);
+
+       if (!no_debug)
+               kdebug("R=%x: No submit", wreq->debug_id);
+       _leave(" = 0");
+       return 0;
+}
+
+/**
+ * netfs_writeback_single - Write back a monolithic payload
+ * @mapping: The mapping to write from
+ * @wbc: Hints from the VM
+ * @iter: Data to write, must be ITER_FOLIOQ.
+ *
+ * Write a monolithic, non-pagecache object back to the server and/or
+ * the cache.
+ */
+int netfs_writeback_single(struct address_space *mapping,
+                          struct writeback_control *wbc,
+                          struct iov_iter *iter)
+{
+       struct netfs_io_request *wreq;
+       struct netfs_inode *ictx = netfs_inode(mapping->host);
+       struct folio_queue *fq;
+       size_t size = iov_iter_count(iter);
+       int ret;
+
+       if (WARN_ON_ONCE(!iov_iter_is_folioq(iter)))
+               return -EIO;
+
+       if (!mutex_trylock(&ictx->wb_lock)) {
+               if (wbc->sync_mode == WB_SYNC_NONE) {
+                       netfs_stat(&netfs_n_wb_lock_skip);
+                       return 0;
+               }
+               netfs_stat(&netfs_n_wb_lock_wait);
+               mutex_lock(&ictx->wb_lock);
+       }
+
+       wreq = netfs_create_write_req(mapping, NULL, 0, NETFS_WRITEBACK_SINGLE);
+       if (IS_ERR(wreq)) {
+               ret = PTR_ERR(wreq);
+               goto couldnt_start;
+       }
+
+       trace_netfs_write(wreq, netfs_write_trace_writeback);
+       netfs_stat(&netfs_n_wh_writepages);
+
+       if (__test_and_set_bit(NETFS_RREQ_UPLOAD_TO_SERVER, &wreq->flags))
+               wreq->netfs_ops->begin_writeback(wreq);
+
+       for (fq = (struct folio_queue *)iter->folioq; fq; fq = fq->next) {
+               for (int slot = 0; slot < folioq_count(fq); slot++) {
+                       struct folio *folio = folioq_folio(fq, slot);
+                       size_t part = umin(folioq_folio_size(fq, slot), size);
+
+                       _debug("wbiter %lx %llx", folio->index, atomic64_read(&wreq->issued_to));
+
+                       ret = netfs_write_folio_single(wreq, folio);
+                       if (ret < 0)
+                               goto stop;
+                       size -= part;
+                       if (size <= 0)
+                               goto stop;
+               }
+       }
+
+stop:
+       for (int s = 0; s < NR_IO_STREAMS; s++)
+               netfs_issue_write(wreq, &wreq->io_streams[s]);
+       smp_wmb(); /* Write lists before ALL_QUEUED. */
+       set_bit(NETFS_RREQ_ALL_QUEUED, &wreq->flags);
+
+       mutex_unlock(&ictx->wb_lock);
+
+       netfs_put_request(wreq, false, netfs_rreq_trace_put_return);
+       _leave(" = %d", ret);
+       return ret;
+
+couldnt_start:
+       mutex_unlock(&ictx->wb_lock);
+       _leave(" = %d", ret);
+       return ret;
+}
+EXPORT_SYMBOL(netfs_writeback_single);
index dd737344cff3a2e81d63313b0f9543c822ad4193..27e62f7d2940036197abe09f8fe130f609fdc756 100644 (file)
@@ -73,6 +73,7 @@ struct netfs_inode {
 #define NETFS_ICTX_UNBUFFERED  1               /* I/O should not use the pagecache */
 #define NETFS_ICTX_WRITETHROUGH        2               /* Write-through caching */
 #define NETFS_ICTX_MODIFIED_ATTR 3             /* Indicate change in mtime/ctime */
+#define NETFS_ICTX_SINGLE_NO_UPLOAD 4          /* Monolithic payload, cache but no upload */
 };
 
 /*
@@ -210,9 +211,11 @@ enum netfs_io_origin {
        NETFS_READAHEAD,                /* This read was triggered by readahead */
        NETFS_READPAGE,                 /* This read is a synchronous read */
        NETFS_READ_GAPS,                /* This read is a synchronous read to fill gaps */
+       NETFS_READ_SINGLE,              /* This read should be treated as a single object */
        NETFS_READ_FOR_WRITE,           /* This read is to prepare a write */
        NETFS_DIO_READ,                 /* This is a direct I/O read */
        NETFS_WRITEBACK,                /* This write was triggered by writepages */
+       NETFS_WRITEBACK_SINGLE,         /* This monolithic write was triggered by writepages */
        NETFS_WRITETHROUGH,             /* This write was made by netfs_perform_write() */
        NETFS_UNBUFFERED_WRITE,         /* This is an unbuffered write */
        NETFS_DIO_WRITE,                /* This is a direct I/O write */
@@ -408,6 +411,13 @@ ssize_t netfs_unbuffered_write_iter_locked(struct kiocb *iocb, struct iov_iter *
                                           struct netfs_group *netfs_group);
 ssize_t netfs_file_write_iter(struct kiocb *iocb, struct iov_iter *from);
 
+/* Single, monolithic object read/write API. */
+void netfs_single_mark_inode_dirty(struct inode *inode);
+ssize_t netfs_read_single(struct inode *inode, struct file *file, struct iov_iter *iter);
+int netfs_writeback_single(struct address_space *mapping,
+                          struct writeback_control *wbc,
+                          struct iov_iter *iter);
+
 /* Address operations API */
 struct readahead_control;
 void netfs_readahead(struct readahead_control *);
index fc237ff23a33e095fec1c5d6d671fc802e89eef6..6df2e7313371ca410c5f3838fea9de9dc7bd2b43 100644 (file)
@@ -21,6 +21,7 @@
        EM(netfs_read_trace_readahead,          "READAHEAD")    \
        EM(netfs_read_trace_readpage,           "READPAGE ")    \
        EM(netfs_read_trace_read_gaps,          "READ-GAPS")    \
+       EM(netfs_read_trace_read_single,        "READ-SNGL")    \
        EM(netfs_read_trace_prefetch_for_write, "PREFETCHW")    \
        E_(netfs_read_trace_write_begin,        "WRITEBEGN")
 
        EM(NETFS_READAHEAD,                     "RA")           \
        EM(NETFS_READPAGE,                      "RP")           \
        EM(NETFS_READ_GAPS,                     "RG")           \
+       EM(NETFS_READ_SINGLE,                   "R1")           \
        EM(NETFS_READ_FOR_WRITE,                "RW")           \
        EM(NETFS_DIO_READ,                      "DR")           \
        EM(NETFS_WRITEBACK,                     "WB")           \
+       EM(NETFS_WRITEBACK_SINGLE,              "W1")           \
        EM(NETFS_WRITETHROUGH,                  "WT")           \
        EM(NETFS_UNBUFFERED_WRITE,              "UW")           \
        EM(NETFS_DIO_WRITE,                     "DW")           \
@@ -47,6 +50,7 @@
        EM(netfs_rreq_trace_assess,             "ASSESS ")      \
        EM(netfs_rreq_trace_copy,               "COPY   ")      \
        EM(netfs_rreq_trace_collect,            "COLLECT")      \
+       EM(netfs_rreq_trace_dirty,              "DIRTY  ")      \
        EM(netfs_rreq_trace_done,               "DONE   ")      \
        EM(netfs_rreq_trace_free,               "FREE   ")      \
        EM(netfs_rreq_trace_redirty,            "REDIRTY")      \