diff options
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/netfs/Makefile | 3 | ||||
| -rw-r--r-- | fs/netfs/internal.h | 6 | ||||
| -rw-r--r-- | fs/netfs/output.c | 363 |
3 files changed, 371 insertions, 1 deletions
diff --git a/fs/netfs/Makefile b/fs/netfs/Makefile index cf3fc847b8ac..c69c6775b8ac 100644 --- a/fs/netfs/Makefile +++ b/fs/netfs/Makefile @@ -7,7 +7,8 @@ netfs-y := \ locking.o \ main.o \ misc.o \ - objects.o + objects.o \ + output.o netfs-$(CONFIG_NETFS_STATS) += stats.o diff --git a/fs/netfs/internal.h b/fs/netfs/internal.h index d72292e40f9b..0f20587f5a9b 100644 --- a/fs/netfs/internal.h +++ b/fs/netfs/internal.h @@ -89,6 +89,12 @@ static inline void netfs_see_request(struct netfs_io_request *rreq, } /* + * output.c + */ +int netfs_begin_write(struct netfs_io_request *wreq, bool may_wait, + enum netfs_write_trace what); + +/* * stats.c */ #ifdef CONFIG_NETFS_STATS diff --git a/fs/netfs/output.c b/fs/netfs/output.c new file mode 100644 index 000000000000..2ad0fd8c32be --- /dev/null +++ b/fs/netfs/output.c @@ -0,0 +1,363 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* Network filesystem high-level write support. + * + * Copyright (C) 2023 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + */ + +#include <linux/fs.h> +#include <linux/mm.h> +#include <linux/pagemap.h> +#include <linux/slab.h> +#include <linux/writeback.h> +#include <linux/pagevec.h> +#include "internal.h" + +/** + * netfs_create_write_request - Create a write operation. + * @wreq: The write request this is storing from. + * @dest: The destination type + * @start: Start of the region this write will modify + * @len: Length of the modification + * @worker: The worker function to handle the write(s) + * + * Allocate a write operation, set it up and add it to the list on a write + * request. + */ +struct netfs_io_subrequest *netfs_create_write_request(struct netfs_io_request *wreq, + enum netfs_io_source dest, + loff_t start, size_t len, + work_func_t worker) +{ + struct netfs_io_subrequest *subreq; + + subreq = netfs_alloc_subrequest(wreq); + if (subreq) { + INIT_WORK(&subreq->work, worker); + subreq->source = dest; + subreq->start = start; + subreq->len = len; + subreq->debug_index = wreq->subreq_counter++; + + switch (subreq->source) { + case NETFS_UPLOAD_TO_SERVER: + netfs_stat(&netfs_n_wh_upload); + break; + case NETFS_WRITE_TO_CACHE: + netfs_stat(&netfs_n_wh_write); + break; + default: + BUG(); + } + + subreq->io_iter = wreq->io_iter; + iov_iter_advance(&subreq->io_iter, subreq->start - wreq->start); + iov_iter_truncate(&subreq->io_iter, subreq->len); + + trace_netfs_sreq_ref(wreq->debug_id, subreq->debug_index, + refcount_read(&subreq->ref), + netfs_sreq_trace_new); + atomic_inc(&wreq->nr_outstanding); + list_add_tail(&subreq->rreq_link, &wreq->subrequests); + trace_netfs_sreq(subreq, netfs_sreq_trace_prepare); + } + + return subreq; +} +EXPORT_SYMBOL(netfs_create_write_request); + +/* + * Process a completed write request once all the component operations have + * been completed. + */ +static void netfs_write_terminated(struct netfs_io_request *wreq, bool was_async) +{ + struct netfs_io_subrequest *subreq; + struct netfs_inode *ctx = netfs_inode(wreq->inode); + + _enter("R=%x[]", wreq->debug_id); + + trace_netfs_rreq(wreq, netfs_rreq_trace_write_done); + + list_for_each_entry(subreq, &wreq->subrequests, rreq_link) { + if (!subreq->error) + continue; + switch (subreq->source) { + case NETFS_UPLOAD_TO_SERVER: + /* Depending on the type of failure, this may prevent + * writeback completion unless we're in disconnected + * mode. + */ + if (!wreq->error) + wreq->error = subreq->error; + break; + + case NETFS_WRITE_TO_CACHE: + /* Failure doesn't prevent writeback completion unless + * we're in disconnected mode. + */ + if (subreq->error != -ENOBUFS) + ctx->ops->invalidate_cache(wreq); + break; + + default: + WARN_ON_ONCE(1); + if (!wreq->error) + wreq->error = -EIO; + return; + } + } + + wreq->cleanup(wreq); + + _debug("finished"); + trace_netfs_rreq(wreq, netfs_rreq_trace_wake_ip); + clear_bit_unlock(NETFS_RREQ_IN_PROGRESS, &wreq->flags); + wake_up_bit(&wreq->flags, NETFS_RREQ_IN_PROGRESS); + + netfs_clear_subrequests(wreq, was_async); + netfs_put_request(wreq, was_async, netfs_rreq_trace_put_complete); +} + +/* + * Deal with the completion of writing the data to the cache. + */ +void netfs_write_subrequest_terminated(void *_op, ssize_t transferred_or_error, + bool was_async) +{ + struct netfs_io_subrequest *subreq = _op; + struct netfs_io_request *wreq = subreq->rreq; + unsigned int u; + + _enter("%x[%x] %zd", wreq->debug_id, subreq->debug_index, transferred_or_error); + + switch (subreq->source) { + case NETFS_UPLOAD_TO_SERVER: + netfs_stat(&netfs_n_wh_upload_done); + break; + case NETFS_WRITE_TO_CACHE: + netfs_stat(&netfs_n_wh_write_done); + break; + case NETFS_INVALID_WRITE: + break; + default: + BUG(); + } + + if (IS_ERR_VALUE(transferred_or_error)) { + subreq->error = transferred_or_error; + trace_netfs_failure(wreq, subreq, transferred_or_error, + netfs_fail_write); + goto failed; + } + + if (WARN(transferred_or_error > subreq->len - subreq->transferred, + "Subreq excess write: R%x[%x] %zd > %zu - %zu", + wreq->debug_id, subreq->debug_index, + transferred_or_error, subreq->len, subreq->transferred)) + transferred_or_error = subreq->len - subreq->transferred; + + subreq->error = 0; + subreq->transferred += transferred_or_error; + + if (iov_iter_count(&subreq->io_iter) != subreq->len - subreq->transferred) + pr_warn("R=%08x[%u] ITER POST-MISMATCH %zx != %zx-%zx %x\n", + wreq->debug_id, subreq->debug_index, + iov_iter_count(&subreq->io_iter), subreq->len, + subreq->transferred, subreq->io_iter.iter_type); + + if (subreq->transferred < subreq->len) + goto incomplete; + + __clear_bit(NETFS_SREQ_NO_PROGRESS, &subreq->flags); +out: + trace_netfs_sreq(subreq, netfs_sreq_trace_terminated); + + /* If we decrement nr_outstanding to 0, the ref belongs to us. */ + u = atomic_dec_return(&wreq->nr_outstanding); + if (u == 0) + netfs_write_terminated(wreq, was_async); + else if (u == 1) + wake_up_var(&wreq->nr_outstanding); + + netfs_put_subrequest(subreq, was_async, netfs_sreq_trace_put_terminated); + return; + +incomplete: + if (transferred_or_error == 0) { + if (__test_and_set_bit(NETFS_SREQ_NO_PROGRESS, &subreq->flags)) { + subreq->error = -ENODATA; + goto failed; + } + } else { + __clear_bit(NETFS_SREQ_NO_PROGRESS, &subreq->flags); + } + + __set_bit(NETFS_SREQ_SHORT_IO, &subreq->flags); + set_bit(NETFS_RREQ_INCOMPLETE_IO, &wreq->flags); + goto out; + +failed: + switch (subreq->source) { + case NETFS_WRITE_TO_CACHE: + netfs_stat(&netfs_n_wh_write_failed); + set_bit(NETFS_RREQ_INCOMPLETE_IO, &wreq->flags); + break; + case NETFS_UPLOAD_TO_SERVER: + netfs_stat(&netfs_n_wh_upload_failed); + set_bit(NETFS_RREQ_FAILED, &wreq->flags); + wreq->error = subreq->error; + break; + default: + break; + } + goto out; +} +EXPORT_SYMBOL(netfs_write_subrequest_terminated); + +static void netfs_write_to_cache_op(struct netfs_io_subrequest *subreq) +{ + struct netfs_io_request *wreq = subreq->rreq; + struct netfs_cache_resources *cres = &wreq->cache_resources; + + trace_netfs_sreq(subreq, netfs_sreq_trace_submit); + + cres->ops->write(cres, subreq->start, &subreq->io_iter, + netfs_write_subrequest_terminated, subreq); +} + +static void netfs_write_to_cache_op_worker(struct work_struct *work) +{ + struct netfs_io_subrequest *subreq = + container_of(work, struct netfs_io_subrequest, work); + + netfs_write_to_cache_op(subreq); +} + +/** + * netfs_queue_write_request - Queue a write request for attention + * @subreq: The write request to be queued + * + * Queue the specified write request for processing by a worker thread. We + * pass the caller's ref on the request to the worker thread. + */ +void netfs_queue_write_request(struct netfs_io_subrequest *subreq) +{ + if (!queue_work(system_unbound_wq, &subreq->work)) + netfs_put_subrequest(subreq, false, netfs_sreq_trace_put_wip); +} +EXPORT_SYMBOL(netfs_queue_write_request); + +/* + * Set up a op for writing to the cache. + */ +static void netfs_set_up_write_to_cache(struct netfs_io_request *wreq) +{ + struct netfs_cache_resources *cres; + struct netfs_io_subrequest *subreq; + struct netfs_inode *ctx = netfs_inode(wreq->inode); + struct fscache_cookie *cookie = netfs_i_cookie(ctx); + loff_t start = wreq->start; + size_t len = wreq->len; + int ret; + + if (!fscache_cookie_enabled(cookie)) { + clear_bit(NETFS_RREQ_WRITE_TO_CACHE, &wreq->flags); + return; + } + + _debug("write to cache"); + subreq = netfs_create_write_request(wreq, NETFS_WRITE_TO_CACHE, start, len, + netfs_write_to_cache_op_worker); + if (!subreq) + return; + + cres = &wreq->cache_resources; + ret = fscache_begin_read_operation(cres, cookie); + if (ret < 0) { + netfs_write_subrequest_terminated(subreq, ret, false); + return; + } + + ret = cres->ops->prepare_write(cres, &start, &len, i_size_read(wreq->inode), + true); + if (ret < 0) { + netfs_write_subrequest_terminated(subreq, ret, false); + return; + } + + netfs_queue_write_request(subreq); +} + +/* + * Begin the process of writing out a chunk of data. + * + * We are given a write request that holds a series of dirty regions and + * (partially) covers a sequence of folios, all of which are present. The + * pages must have been marked as writeback as appropriate. + * + * We need to perform the following steps: + * + * (1) If encrypting, create an output buffer and encrypt each block of the + * data into it, otherwise the output buffer will point to the original + * folios. + * + * (2) If the data is to be cached, set up a write op for the entire output + * buffer to the cache, if the cache wants to accept it. + * + * (3) If the data is to be uploaded (ie. not merely cached): + * + * (a) If the data is to be compressed, create a compression buffer and + * compress the data into it. + * + * (b) For each destination we want to upload to, set up write ops to write + * to that destination. We may need multiple writes if the data is not + * contiguous or the span exceeds wsize for a server. + */ +int netfs_begin_write(struct netfs_io_request *wreq, bool may_wait, + enum netfs_write_trace what) +{ + struct netfs_inode *ctx = netfs_inode(wreq->inode); + + _enter("R=%x %llx-%llx f=%lx", + wreq->debug_id, wreq->start, wreq->start + wreq->len - 1, + wreq->flags); + + trace_netfs_write(wreq, what); + if (wreq->len == 0 || wreq->iter.count == 0) { + pr_err("Zero-sized write [R=%x]\n", wreq->debug_id); + return -EIO; + } + + wreq->io_iter = wreq->iter; + + /* ->outstanding > 0 carries a ref */ + netfs_get_request(wreq, netfs_rreq_trace_get_for_outstanding); + atomic_set(&wreq->nr_outstanding, 1); + + /* Start the encryption/compression going. We can do that in the + * background whilst we generate a list of write ops that we want to + * perform. + */ + // TODO: Encrypt or compress the region as appropriate + + /* We need to write all of the region to the cache */ + if (test_bit(NETFS_RREQ_WRITE_TO_CACHE, &wreq->flags)) + netfs_set_up_write_to_cache(wreq); + + /* However, we don't necessarily write all of the region to the server. + * Caching of reads is being managed this way also. + */ + if (test_bit(NETFS_RREQ_UPLOAD_TO_SERVER, &wreq->flags)) + ctx->ops->create_write_requests(wreq, wreq->start, wreq->len); + + if (atomic_dec_and_test(&wreq->nr_outstanding)) + netfs_write_terminated(wreq, false); + + if (!may_wait) + return -EIOCBQUEUED; + + wait_on_bit(&wreq->flags, NETFS_RREQ_IN_PROGRESS, + TASK_UNINTERRUPTIBLE); + return wreq->error; +} |