From 5fb70e7275a61dd404f684370e1add7fe0ebe9c5 Mon Sep 17 00:00:00 2001 From: David Howells Date: Mon, 18 Mar 2024 20:29:53 +0000 Subject: [PATCH] netfs, 9p: Implement helpers for new write code Implement the helpers for the new write code in 9p. There's now an optional ->prepare_write() that allows the filesystem to set the parameters for the next write, such as maximum size and maximum segment count, and an ->issue_write() that is called to initiate an (asynchronous) write operation. Signed-off-by: David Howells Reviewed-by: Jeff Layton cc: Eric Van Hensbergen cc: Latchesar Ionkov cc: Dominique Martinet cc: Christian Schoenebeck cc: v9fs@lists.linux.dev cc: netfs@lists.linux.dev cc: linux-fsdevel@vger.kernel.org --- fs/9p/vfs_addr.c | 48 ++++++++++++++++++++++++++++++++++++++++ include/net/9p/client.h | 2 ++ net/9p/Kconfig | 1 + net/9p/client.c | 49 +++++++++++++++++++++++++++++++++++++++++ 4 files changed, 100 insertions(+) diff --git a/fs/9p/vfs_addr.c b/fs/9p/vfs_addr.c index 5a943c122d83..07d03efdd594 100644 --- a/fs/9p/vfs_addr.c +++ b/fs/9p/vfs_addr.c @@ -26,6 +26,40 @@ #include "cache.h" #include "fid.h" +/* + * Writeback calls this when it finds a folio that needs uploading. This isn't + * called if writeback only has copy-to-cache to deal with. + */ +static void v9fs_begin_writeback(struct netfs_io_request *wreq) +{ + struct p9_fid *fid; + + fid = v9fs_fid_find_inode(wreq->inode, true, INVALID_UID, true); + if (!fid) { + WARN_ONCE(1, "folio expected an open fid inode->i_ino=%lx\n", + wreq->inode->i_ino); + return; + } + + wreq->wsize = fid->clnt->msize - P9_IOHDRSZ; + if (fid->iounit) + wreq->wsize = min(wreq->wsize, fid->iounit); + wreq->netfs_priv = fid; + wreq->io_streams[0].avail = true; +} + +/* + * Issue a subrequest to write to the server. + */ +static void v9fs_issue_write(struct netfs_io_subrequest *subreq) +{ + struct p9_fid *fid = subreq->rreq->netfs_priv; + int err, len; + + len = p9_client_write(fid, subreq->start, &subreq->io_iter, &err); + netfs_write_subrequest_terminated(subreq, len ?: err, false); +} + static void v9fs_upload_to_server(struct netfs_io_subrequest *subreq) { struct p9_fid *fid = subreq->rreq->netfs_priv; @@ -92,6 +126,14 @@ static int v9fs_init_request(struct netfs_io_request *rreq, struct file *file) rreq->origin == NETFS_UNBUFFERED_WRITE || rreq->origin == NETFS_DIO_WRITE); +#if 0 // TODO: Cut over + if (rreq->origin == NETFS_WRITEBACK) + return 0; /* We don't get the write handle until we find we + * have actually dirty data and not just + * copy-to-cache data. + */ +#endif + if (file) { fid = file->private_data; if (!fid) @@ -103,6 +145,10 @@ static int v9fs_init_request(struct netfs_io_request *rreq, struct file *file) goto no_fid; } + rreq->wsize = fid->clnt->msize - P9_IOHDRSZ; + if (fid->iounit) + rreq->wsize = min(rreq->wsize, fid->iounit); + /* we might need to read from a fid that was opened write-only * for read-modify-write of page cache, use the writeback fid * for that */ @@ -131,6 +177,8 @@ const struct netfs_request_ops v9fs_req_ops = { .init_request = v9fs_init_request, .free_request = v9fs_free_request, .issue_read = v9fs_issue_read, + .begin_writeback = v9fs_begin_writeback, + .issue_write = v9fs_issue_write, .create_write_requests = v9fs_create_write_requests, }; diff --git a/include/net/9p/client.h b/include/net/9p/client.h index 78ebcf782ce5..4f785098c67a 100644 --- a/include/net/9p/client.h +++ b/include/net/9p/client.h @@ -207,6 +207,8 @@ int p9_client_read(struct p9_fid *fid, u64 offset, struct iov_iter *to, int *err int p9_client_read_once(struct p9_fid *fid, u64 offset, struct iov_iter *to, int *err); int p9_client_write(struct p9_fid *fid, u64 offset, struct iov_iter *from, int *err); +struct netfs_io_subrequest; +void p9_client_write_subreq(struct netfs_io_subrequest *subreq); int p9_client_readdir(struct p9_fid *fid, char *data, u32 count, u64 offset); int p9dirent_read(struct p9_client *clnt, char *buf, int len, struct p9_dirent *dirent); diff --git a/net/9p/Kconfig b/net/9p/Kconfig index 00ebce9e5a65..bcdab9c23b40 100644 --- a/net/9p/Kconfig +++ b/net/9p/Kconfig @@ -5,6 +5,7 @@ menuconfig NET_9P tristate "Plan 9 Resource Sharing Support (9P2000)" + select NETFS_SUPPORT help If you say Y here, you will get experimental support for Plan 9 resource sharing via the 9P2000 protocol. diff --git a/net/9p/client.c b/net/9p/client.c index f7e90b4769bb..00774656eeac 100644 --- a/net/9p/client.c +++ b/net/9p/client.c @@ -18,6 +18,7 @@ #include #include #include +#include #include #include #include @@ -1661,6 +1662,54 @@ p9_client_write(struct p9_fid *fid, u64 offset, struct iov_iter *from, int *err) } EXPORT_SYMBOL(p9_client_write); +void +p9_client_write_subreq(struct netfs_io_subrequest *subreq) +{ + struct netfs_io_request *wreq = subreq->rreq; + struct p9_fid *fid = wreq->netfs_priv; + struct p9_client *clnt = fid->clnt; + struct p9_req_t *req; + unsigned long long start = subreq->start + subreq->transferred; + int written, len = subreq->len - subreq->transferred; + int err; + + p9_debug(P9_DEBUG_9P, ">>> TWRITE fid %d offset %llu len %d\n", + fid->fid, start, len); + + /* Don't bother zerocopy for small IO (< 1024) */ + if (clnt->trans_mod->zc_request && len > 1024) { + req = p9_client_zc_rpc(clnt, P9_TWRITE, NULL, &subreq->io_iter, + 0, wreq->len, P9_ZC_HDR_SZ, "dqd", + fid->fid, start, len); + } else { + req = p9_client_rpc(clnt, P9_TWRITE, "dqV", fid->fid, + start, len, &subreq->io_iter); + } + if (IS_ERR(req)) { + netfs_write_subrequest_terminated(subreq, PTR_ERR(req), false); + return; + } + + err = p9pdu_readf(&req->rc, clnt->proto_version, "d", &written); + if (err) { + trace_9p_protocol_dump(clnt, &req->rc); + p9_req_put(clnt, req); + netfs_write_subrequest_terminated(subreq, err, false); + return; + } + + if (written > len) { + pr_err("bogus RWRITE count (%d > %u)\n", written, len); + written = len; + } + + p9_debug(P9_DEBUG_9P, "<<< RWRITE count %d\n", len); + + p9_req_put(clnt, req); + netfs_write_subrequest_terminated(subreq, written, false); +} +EXPORT_SYMBOL(p9_client_write_subreq); + struct p9_wstat *p9_client_stat(struct p9_fid *fid) { int err;