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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
commit | 2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch) | |
tree | 848558de17fb3008cdf4d861b01ac7781903ce39 /fs/afs/write.c | |
parent | Initial commit. (diff) | |
download | linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip |
Adding upstream version 6.1.76.upstream/6.1.76upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | fs/afs/write.c | 1040 |
1 files changed, 1040 insertions, 0 deletions
diff --git a/fs/afs/write.c b/fs/afs/write.c new file mode 100644 index 000000000..3ecc212b6 --- /dev/null +++ b/fs/afs/write.c @@ -0,0 +1,1040 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* handling of writes to regular files and writing back to the server + * + * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + */ + +#include <linux/backing-dev.h> +#include <linux/slab.h> +#include <linux/fs.h> +#include <linux/pagemap.h> +#include <linux/writeback.h> +#include <linux/pagevec.h> +#include <linux/netfs.h> +#include "internal.h" + +static void afs_write_to_cache(struct afs_vnode *vnode, loff_t start, size_t len, + loff_t i_size, bool caching); + +#ifdef CONFIG_AFS_FSCACHE +/* + * Mark a page as having been made dirty and thus needing writeback. We also + * need to pin the cache object to write back to. + */ +bool afs_dirty_folio(struct address_space *mapping, struct folio *folio) +{ + return fscache_dirty_folio(mapping, folio, + afs_vnode_cache(AFS_FS_I(mapping->host))); +} +static void afs_folio_start_fscache(bool caching, struct folio *folio) +{ + if (caching) + folio_start_fscache(folio); +} +#else +static void afs_folio_start_fscache(bool caching, struct folio *folio) +{ +} +#endif + +/* + * prepare to perform part of a write to a page + */ +int afs_write_begin(struct file *file, struct address_space *mapping, + loff_t pos, unsigned len, + struct page **_page, void **fsdata) +{ + struct afs_vnode *vnode = AFS_FS_I(file_inode(file)); + struct folio *folio; + unsigned long priv; + unsigned f, from; + unsigned t, to; + pgoff_t index; + int ret; + + _enter("{%llx:%llu},%llx,%x", + vnode->fid.vid, vnode->fid.vnode, pos, len); + + /* Prefetch area to be written into the cache if we're caching this + * file. We need to do this before we get a lock on the page in case + * there's more than one writer competing for the same cache block. + */ + ret = netfs_write_begin(&vnode->netfs, file, mapping, pos, len, &folio, fsdata); + if (ret < 0) + return ret; + + index = folio_index(folio); + from = pos - index * PAGE_SIZE; + to = from + len; + +try_again: + /* See if this page is already partially written in a way that we can + * merge the new write with. + */ + if (folio_test_private(folio)) { + priv = (unsigned long)folio_get_private(folio); + f = afs_folio_dirty_from(folio, priv); + t = afs_folio_dirty_to(folio, priv); + ASSERTCMP(f, <=, t); + + if (folio_test_writeback(folio)) { + trace_afs_folio_dirty(vnode, tracepoint_string("alrdy"), folio); + goto flush_conflicting_write; + } + /* If the file is being filled locally, allow inter-write + * spaces to be merged into writes. If it's not, only write + * back what the user gives us. + */ + if (!test_bit(AFS_VNODE_NEW_CONTENT, &vnode->flags) && + (to < f || from > t)) + goto flush_conflicting_write; + } + + *_page = folio_file_page(folio, pos / PAGE_SIZE); + _leave(" = 0"); + return 0; + + /* The previous write and this write aren't adjacent or overlapping, so + * flush the page out. + */ +flush_conflicting_write: + _debug("flush conflict"); + ret = folio_write_one(folio); + if (ret < 0) + goto error; + + ret = folio_lock_killable(folio); + if (ret < 0) + goto error; + goto try_again; + +error: + folio_put(folio); + _leave(" = %d", ret); + return ret; +} + +/* + * finalise part of a write to a page + */ +int afs_write_end(struct file *file, struct address_space *mapping, + loff_t pos, unsigned len, unsigned copied, + struct page *subpage, void *fsdata) +{ + struct folio *folio = page_folio(subpage); + struct afs_vnode *vnode = AFS_FS_I(file_inode(file)); + unsigned long priv; + unsigned int f, from = offset_in_folio(folio, pos); + unsigned int t, to = from + copied; + loff_t i_size, write_end_pos; + + _enter("{%llx:%llu},{%lx}", + vnode->fid.vid, vnode->fid.vnode, folio_index(folio)); + + if (!folio_test_uptodate(folio)) { + if (copied < len) { + copied = 0; + goto out; + } + + folio_mark_uptodate(folio); + } + + if (copied == 0) + goto out; + + write_end_pos = pos + copied; + + i_size = i_size_read(&vnode->netfs.inode); + if (write_end_pos > i_size) { + write_seqlock(&vnode->cb_lock); + i_size = i_size_read(&vnode->netfs.inode); + if (write_end_pos > i_size) + afs_set_i_size(vnode, write_end_pos); + write_sequnlock(&vnode->cb_lock); + fscache_update_cookie(afs_vnode_cache(vnode), NULL, &write_end_pos); + } + + if (folio_test_private(folio)) { + priv = (unsigned long)folio_get_private(folio); + f = afs_folio_dirty_from(folio, priv); + t = afs_folio_dirty_to(folio, priv); + if (from < f) + f = from; + if (to > t) + t = to; + priv = afs_folio_dirty(folio, f, t); + folio_change_private(folio, (void *)priv); + trace_afs_folio_dirty(vnode, tracepoint_string("dirty+"), folio); + } else { + priv = afs_folio_dirty(folio, from, to); + folio_attach_private(folio, (void *)priv); + trace_afs_folio_dirty(vnode, tracepoint_string("dirty"), folio); + } + + if (folio_mark_dirty(folio)) + _debug("dirtied %lx", folio_index(folio)); + +out: + folio_unlock(folio); + folio_put(folio); + return copied; +} + +/* + * kill all the pages in the given range + */ +static void afs_kill_pages(struct address_space *mapping, + loff_t start, loff_t len) +{ + struct afs_vnode *vnode = AFS_FS_I(mapping->host); + struct folio *folio; + pgoff_t index = start / PAGE_SIZE; + pgoff_t last = (start + len - 1) / PAGE_SIZE, next; + + _enter("{%llx:%llu},%llx @%llx", + vnode->fid.vid, vnode->fid.vnode, len, start); + + do { + _debug("kill %lx (to %lx)", index, last); + + folio = filemap_get_folio(mapping, index); + if (!folio) { + next = index + 1; + continue; + } + + next = folio_next_index(folio); + + folio_clear_uptodate(folio); + folio_end_writeback(folio); + folio_lock(folio); + generic_error_remove_page(mapping, &folio->page); + folio_unlock(folio); + folio_put(folio); + + } while (index = next, index <= last); + + _leave(""); +} + +/* + * Redirty all the pages in a given range. + */ +static void afs_redirty_pages(struct writeback_control *wbc, + struct address_space *mapping, + loff_t start, loff_t len) +{ + struct afs_vnode *vnode = AFS_FS_I(mapping->host); + struct folio *folio; + pgoff_t index = start / PAGE_SIZE; + pgoff_t last = (start + len - 1) / PAGE_SIZE, next; + + _enter("{%llx:%llu},%llx @%llx", + vnode->fid.vid, vnode->fid.vnode, len, start); + + do { + _debug("redirty %llx @%llx", len, start); + + folio = filemap_get_folio(mapping, index); + if (!folio) { + next = index + 1; + continue; + } + + next = index + folio_nr_pages(folio); + folio_redirty_for_writepage(wbc, folio); + folio_end_writeback(folio); + folio_put(folio); + } while (index = next, index <= last); + + _leave(""); +} + +/* + * completion of write to server + */ +static void afs_pages_written_back(struct afs_vnode *vnode, loff_t start, unsigned int len) +{ + struct address_space *mapping = vnode->netfs.inode.i_mapping; + struct folio *folio; + pgoff_t end; + + XA_STATE(xas, &mapping->i_pages, start / PAGE_SIZE); + + _enter("{%llx:%llu},{%x @%llx}", + vnode->fid.vid, vnode->fid.vnode, len, start); + + rcu_read_lock(); + + end = (start + len - 1) / PAGE_SIZE; + xas_for_each(&xas, folio, end) { + if (!folio_test_writeback(folio)) { + kdebug("bad %x @%llx page %lx %lx", + len, start, folio_index(folio), end); + ASSERT(folio_test_writeback(folio)); + } + + trace_afs_folio_dirty(vnode, tracepoint_string("clear"), folio); + folio_detach_private(folio); + folio_end_writeback(folio); + } + + rcu_read_unlock(); + + afs_prune_wb_keys(vnode); + _leave(""); +} + +/* + * Find a key to use for the writeback. We cached the keys used to author the + * writes on the vnode. *_wbk will contain the last writeback key used or NULL + * and we need to start from there if it's set. + */ +static int afs_get_writeback_key(struct afs_vnode *vnode, + struct afs_wb_key **_wbk) +{ + struct afs_wb_key *wbk = NULL; + struct list_head *p; + int ret = -ENOKEY, ret2; + + spin_lock(&vnode->wb_lock); + if (*_wbk) + p = (*_wbk)->vnode_link.next; + else + p = vnode->wb_keys.next; + + while (p != &vnode->wb_keys) { + wbk = list_entry(p, struct afs_wb_key, vnode_link); + _debug("wbk %u", key_serial(wbk->key)); + ret2 = key_validate(wbk->key); + if (ret2 == 0) { + refcount_inc(&wbk->usage); + _debug("USE WB KEY %u", key_serial(wbk->key)); + break; + } + + wbk = NULL; + if (ret == -ENOKEY) + ret = ret2; + p = p->next; + } + + spin_unlock(&vnode->wb_lock); + if (*_wbk) + afs_put_wb_key(*_wbk); + *_wbk = wbk; + return 0; +} + +static void afs_store_data_success(struct afs_operation *op) +{ + struct afs_vnode *vnode = op->file[0].vnode; + + op->ctime = op->file[0].scb.status.mtime_client; + afs_vnode_commit_status(op, &op->file[0]); + if (op->error == 0) { + if (!op->store.laundering) + afs_pages_written_back(vnode, op->store.pos, op->store.size); + afs_stat_v(vnode, n_stores); + atomic_long_add(op->store.size, &afs_v2net(vnode)->n_store_bytes); + } +} + +static const struct afs_operation_ops afs_store_data_operation = { + .issue_afs_rpc = afs_fs_store_data, + .issue_yfs_rpc = yfs_fs_store_data, + .success = afs_store_data_success, +}; + +/* + * write to a file + */ +static int afs_store_data(struct afs_vnode *vnode, struct iov_iter *iter, loff_t pos, + bool laundering) +{ + struct afs_operation *op; + struct afs_wb_key *wbk = NULL; + loff_t size = iov_iter_count(iter); + int ret = -ENOKEY; + + _enter("%s{%llx:%llu.%u},%llx,%llx", + vnode->volume->name, + vnode->fid.vid, + vnode->fid.vnode, + vnode->fid.unique, + size, pos); + + ret = afs_get_writeback_key(vnode, &wbk); + if (ret) { + _leave(" = %d [no keys]", ret); + return ret; + } + + op = afs_alloc_operation(wbk->key, vnode->volume); + if (IS_ERR(op)) { + afs_put_wb_key(wbk); + return -ENOMEM; + } + + afs_op_set_vnode(op, 0, vnode); + op->file[0].dv_delta = 1; + op->file[0].modification = true; + op->store.pos = pos; + op->store.size = size; + op->store.laundering = laundering; + op->flags |= AFS_OPERATION_UNINTR; + op->ops = &afs_store_data_operation; + +try_next_key: + afs_begin_vnode_operation(op); + + op->store.write_iter = iter; + op->store.i_size = max(pos + size, vnode->netfs.remote_i_size); + op->mtime = vnode->netfs.inode.i_mtime; + + afs_wait_for_operation(op); + + switch (op->error) { + case -EACCES: + case -EPERM: + case -ENOKEY: + case -EKEYEXPIRED: + case -EKEYREJECTED: + case -EKEYREVOKED: + _debug("next"); + + ret = afs_get_writeback_key(vnode, &wbk); + if (ret == 0) { + key_put(op->key); + op->key = key_get(wbk->key); + goto try_next_key; + } + break; + } + + afs_put_wb_key(wbk); + _leave(" = %d", op->error); + return afs_put_operation(op); +} + +/* + * Extend the region to be written back to include subsequent contiguously + * dirty pages if possible, but don't sleep while doing so. + * + * If this page holds new content, then we can include filler zeros in the + * writeback. + */ +static void afs_extend_writeback(struct address_space *mapping, + struct afs_vnode *vnode, + long *_count, + loff_t start, + loff_t max_len, + bool new_content, + bool caching, + unsigned int *_len) +{ + struct pagevec pvec; + struct folio *folio; + unsigned long priv; + unsigned int psize, filler = 0; + unsigned int f, t; + loff_t len = *_len; + pgoff_t index = (start + len) / PAGE_SIZE; + bool stop = true; + unsigned int i; + + XA_STATE(xas, &mapping->i_pages, index); + pagevec_init(&pvec); + + do { + /* Firstly, we gather up a batch of contiguous dirty pages + * under the RCU read lock - but we can't clear the dirty flags + * there if any of those pages are mapped. + */ + rcu_read_lock(); + + xas_for_each(&xas, folio, ULONG_MAX) { + stop = true; + if (xas_retry(&xas, folio)) + continue; + if (xa_is_value(folio)) + break; + if (folio_index(folio) != index) + break; + + if (!folio_try_get_rcu(folio)) { + xas_reset(&xas); + continue; + } + + /* Has the page moved or been split? */ + if (unlikely(folio != xas_reload(&xas))) { + folio_put(folio); + break; + } + + if (!folio_trylock(folio)) { + folio_put(folio); + break; + } + if (!folio_test_dirty(folio) || + folio_test_writeback(folio) || + folio_test_fscache(folio)) { + folio_unlock(folio); + folio_put(folio); + break; + } + + psize = folio_size(folio); + priv = (unsigned long)folio_get_private(folio); + f = afs_folio_dirty_from(folio, priv); + t = afs_folio_dirty_to(folio, priv); + if (f != 0 && !new_content) { + folio_unlock(folio); + folio_put(folio); + break; + } + + len += filler + t; + filler = psize - t; + if (len >= max_len || *_count <= 0) + stop = true; + else if (t == psize || new_content) + stop = false; + + index += folio_nr_pages(folio); + if (!pagevec_add(&pvec, &folio->page)) + break; + if (stop) + break; + } + + if (!stop) + xas_pause(&xas); + rcu_read_unlock(); + + /* Now, if we obtained any pages, we can shift them to being + * writable and mark them for caching. + */ + if (!pagevec_count(&pvec)) + break; + + for (i = 0; i < pagevec_count(&pvec); i++) { + folio = page_folio(pvec.pages[i]); + trace_afs_folio_dirty(vnode, tracepoint_string("store+"), folio); + + if (!folio_clear_dirty_for_io(folio)) + BUG(); + if (folio_start_writeback(folio)) + BUG(); + afs_folio_start_fscache(caching, folio); + + *_count -= folio_nr_pages(folio); + folio_unlock(folio); + } + + pagevec_release(&pvec); + cond_resched(); + } while (!stop); + + *_len = len; +} + +/* + * Synchronously write back the locked page and any subsequent non-locked dirty + * pages. + */ +static ssize_t afs_write_back_from_locked_folio(struct address_space *mapping, + struct writeback_control *wbc, + struct folio *folio, + loff_t start, loff_t end) +{ + struct afs_vnode *vnode = AFS_FS_I(mapping->host); + struct iov_iter iter; + unsigned long priv; + unsigned int offset, to, len, max_len; + loff_t i_size = i_size_read(&vnode->netfs.inode); + bool new_content = test_bit(AFS_VNODE_NEW_CONTENT, &vnode->flags); + bool caching = fscache_cookie_enabled(afs_vnode_cache(vnode)); + long count = wbc->nr_to_write; + int ret; + + _enter(",%lx,%llx-%llx", folio_index(folio), start, end); + + if (folio_start_writeback(folio)) + BUG(); + afs_folio_start_fscache(caching, folio); + + count -= folio_nr_pages(folio); + + /* Find all consecutive lockable dirty pages that have contiguous + * written regions, stopping when we find a page that is not + * immediately lockable, is not dirty or is missing, or we reach the + * end of the range. + */ + priv = (unsigned long)folio_get_private(folio); + offset = afs_folio_dirty_from(folio, priv); + to = afs_folio_dirty_to(folio, priv); + trace_afs_folio_dirty(vnode, tracepoint_string("store"), folio); + + len = to - offset; + start += offset; + if (start < i_size) { + /* Trim the write to the EOF; the extra data is ignored. Also + * put an upper limit on the size of a single storedata op. + */ + max_len = 65536 * 4096; + max_len = min_t(unsigned long long, max_len, end - start + 1); + max_len = min_t(unsigned long long, max_len, i_size - start); + + if (len < max_len && + (to == folio_size(folio) || new_content)) + afs_extend_writeback(mapping, vnode, &count, + start, max_len, new_content, + caching, &len); + len = min_t(loff_t, len, max_len); + } + + /* We now have a contiguous set of dirty pages, each with writeback + * set; the first page is still locked at this point, but all the rest + * have been unlocked. + */ + folio_unlock(folio); + + if (start < i_size) { + _debug("write back %x @%llx [%llx]", len, start, i_size); + + /* Speculatively write to the cache. We have to fix this up + * later if the store fails. + */ + afs_write_to_cache(vnode, start, len, i_size, caching); + + iov_iter_xarray(&iter, ITER_SOURCE, &mapping->i_pages, start, len); + ret = afs_store_data(vnode, &iter, start, false); + } else { + _debug("write discard %x @%llx [%llx]", len, start, i_size); + + /* The dirty region was entirely beyond the EOF. */ + fscache_clear_page_bits(mapping, start, len, caching); + afs_pages_written_back(vnode, start, len); + ret = 0; + } + + switch (ret) { + case 0: + wbc->nr_to_write = count; + ret = len; + break; + + default: + pr_notice("kAFS: Unexpected error from FS.StoreData %d\n", ret); + fallthrough; + case -EACCES: + case -EPERM: + case -ENOKEY: + case -EKEYEXPIRED: + case -EKEYREJECTED: + case -EKEYREVOKED: + case -ENETRESET: + afs_redirty_pages(wbc, mapping, start, len); + mapping_set_error(mapping, ret); + break; + + case -EDQUOT: + case -ENOSPC: + afs_redirty_pages(wbc, mapping, start, len); + mapping_set_error(mapping, -ENOSPC); + break; + + case -EROFS: + case -EIO: + case -EREMOTEIO: + case -EFBIG: + case -ENOENT: + case -ENOMEDIUM: + case -ENXIO: + trace_afs_file_error(vnode, ret, afs_file_error_writeback_fail); + afs_kill_pages(mapping, start, len); + mapping_set_error(mapping, ret); + break; + } + + _leave(" = %d", ret); + return ret; +} + +/* + * write a page back to the server + * - the caller locked the page for us + */ +int afs_writepage(struct page *subpage, struct writeback_control *wbc) +{ + struct folio *folio = page_folio(subpage); + ssize_t ret; + loff_t start; + + _enter("{%lx},", folio_index(folio)); + +#ifdef CONFIG_AFS_FSCACHE + folio_wait_fscache(folio); +#endif + + start = folio_index(folio) * PAGE_SIZE; + ret = afs_write_back_from_locked_folio(folio_mapping(folio), wbc, + folio, start, LLONG_MAX - start); + if (ret < 0) { + _leave(" = %zd", ret); + return ret; + } + + _leave(" = 0"); + return 0; +} + +/* + * write a region of pages back to the server + */ +static int afs_writepages_region(struct address_space *mapping, + struct writeback_control *wbc, + loff_t start, loff_t end, loff_t *_next) +{ + struct folio *folio; + struct page *head_page; + ssize_t ret; + int n, skips = 0; + + _enter("%llx,%llx,", start, end); + + do { + pgoff_t index = start / PAGE_SIZE; + + n = find_get_pages_range_tag(mapping, &index, end / PAGE_SIZE, + PAGECACHE_TAG_DIRTY, 1, &head_page); + if (!n) + break; + + folio = page_folio(head_page); + start = folio_pos(folio); /* May regress with THPs */ + + _debug("wback %lx", folio_index(folio)); + + /* At this point we hold neither the i_pages lock nor the + * page lock: the page may be truncated or invalidated + * (changing page->mapping to NULL), or even swizzled + * back from swapper_space to tmpfs file mapping + */ + if (wbc->sync_mode != WB_SYNC_NONE) { + ret = folio_lock_killable(folio); + if (ret < 0) { + folio_put(folio); + return ret; + } + } else { + if (!folio_trylock(folio)) { + folio_put(folio); + return 0; + } + } + + if (folio_mapping(folio) != mapping || + !folio_test_dirty(folio)) { + start += folio_size(folio); + folio_unlock(folio); + folio_put(folio); + continue; + } + + if (folio_test_writeback(folio) || + folio_test_fscache(folio)) { + folio_unlock(folio); + if (wbc->sync_mode != WB_SYNC_NONE) { + folio_wait_writeback(folio); +#ifdef CONFIG_AFS_FSCACHE + folio_wait_fscache(folio); +#endif + } else { + start += folio_size(folio); + } + folio_put(folio); + if (wbc->sync_mode == WB_SYNC_NONE) { + if (skips >= 5 || need_resched()) + break; + skips++; + } + continue; + } + + if (!folio_clear_dirty_for_io(folio)) + BUG(); + ret = afs_write_back_from_locked_folio(mapping, wbc, folio, start, end); + folio_put(folio); + if (ret < 0) { + _leave(" = %zd", ret); + return ret; + } + + start += ret; + + cond_resched(); + } while (wbc->nr_to_write > 0); + + *_next = start; + _leave(" = 0 [%llx]", *_next); + return 0; +} + +/* + * write some of the pending data back to the server + */ +int afs_writepages(struct address_space *mapping, + struct writeback_control *wbc) +{ + struct afs_vnode *vnode = AFS_FS_I(mapping->host); + loff_t start, next; + int ret; + + _enter(""); + + /* We have to be careful as we can end up racing with setattr() + * truncating the pagecache since the caller doesn't take a lock here + * to prevent it. + */ + if (wbc->sync_mode == WB_SYNC_ALL) + down_read(&vnode->validate_lock); + else if (!down_read_trylock(&vnode->validate_lock)) + return 0; + + if (wbc->range_cyclic) { + start = mapping->writeback_index * PAGE_SIZE; + ret = afs_writepages_region(mapping, wbc, start, LLONG_MAX, &next); + if (ret == 0) { + mapping->writeback_index = next / PAGE_SIZE; + if (start > 0 && wbc->nr_to_write > 0) { + ret = afs_writepages_region(mapping, wbc, 0, + start, &next); + if (ret == 0) + mapping->writeback_index = + next / PAGE_SIZE; + } + } + } else if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX) { + ret = afs_writepages_region(mapping, wbc, 0, LLONG_MAX, &next); + if (wbc->nr_to_write > 0 && ret == 0) + mapping->writeback_index = next / PAGE_SIZE; + } else { + ret = afs_writepages_region(mapping, wbc, + wbc->range_start, wbc->range_end, &next); + } + + up_read(&vnode->validate_lock); + _leave(" = %d", ret); + return ret; +} + +/* + * write to an AFS file + */ +ssize_t afs_file_write(struct kiocb *iocb, struct iov_iter *from) +{ + struct afs_vnode *vnode = AFS_FS_I(file_inode(iocb->ki_filp)); + struct afs_file *af = iocb->ki_filp->private_data; + ssize_t result; + size_t count = iov_iter_count(from); + + _enter("{%llx:%llu},{%zu},", + vnode->fid.vid, vnode->fid.vnode, count); + + if (IS_SWAPFILE(&vnode->netfs.inode)) { + printk(KERN_INFO + "AFS: Attempt to write to active swap file!\n"); + return -EBUSY; + } + + if (!count) + return 0; + + result = afs_validate(vnode, af->key); + if (result < 0) + return result; + + result = generic_file_write_iter(iocb, from); + + _leave(" = %zd", result); + return result; +} + +/* + * flush any dirty pages for this process, and check for write errors. + * - the return status from this call provides a reliable indication of + * whether any write errors occurred for this process. + */ +int afs_fsync(struct file *file, loff_t start, loff_t end, int datasync) +{ + struct afs_vnode *vnode = AFS_FS_I(file_inode(file)); + struct afs_file *af = file->private_data; + int ret; + + _enter("{%llx:%llu},{n=%pD},%d", + vnode->fid.vid, vnode->fid.vnode, file, + datasync); + + ret = afs_validate(vnode, af->key); + if (ret < 0) + return ret; + + return file_write_and_wait_range(file, start, end); +} + +/* + * notification that a previously read-only page is about to become writable + * - if it returns an error, the caller will deliver a bus error signal + */ +vm_fault_t afs_page_mkwrite(struct vm_fault *vmf) +{ + struct folio *folio = page_folio(vmf->page); + struct file *file = vmf->vma->vm_file; + struct inode *inode = file_inode(file); + struct afs_vnode *vnode = AFS_FS_I(inode); + struct afs_file *af = file->private_data; + unsigned long priv; + vm_fault_t ret = VM_FAULT_RETRY; + + _enter("{{%llx:%llu}},{%lx}", vnode->fid.vid, vnode->fid.vnode, folio_index(folio)); + + afs_validate(vnode, af->key); + + sb_start_pagefault(inode->i_sb); + + /* Wait for the page to be written to the cache before we allow it to + * be modified. We then assume the entire page will need writing back. + */ +#ifdef CONFIG_AFS_FSCACHE + if (folio_test_fscache(folio) && + folio_wait_fscache_killable(folio) < 0) + goto out; +#endif + + if (folio_wait_writeback_killable(folio)) + goto out; + + if (folio_lock_killable(folio) < 0) + goto out; + + /* We mustn't change folio->private until writeback is complete as that + * details the portion of the page we need to write back and we might + * need to redirty the page if there's a problem. + */ + if (folio_wait_writeback_killable(folio) < 0) { + folio_unlock(folio); + goto out; + } + + priv = afs_folio_dirty(folio, 0, folio_size(folio)); + priv = afs_folio_dirty_mmapped(priv); + if (folio_test_private(folio)) { + folio_change_private(folio, (void *)priv); + trace_afs_folio_dirty(vnode, tracepoint_string("mkwrite+"), folio); + } else { + folio_attach_private(folio, (void *)priv); + trace_afs_folio_dirty(vnode, tracepoint_string("mkwrite"), folio); + } + file_update_time(file); + + ret = VM_FAULT_LOCKED; +out: + sb_end_pagefault(inode->i_sb); + return ret; +} + +/* + * Prune the keys cached for writeback. The caller must hold vnode->wb_lock. + */ +void afs_prune_wb_keys(struct afs_vnode *vnode) +{ + LIST_HEAD(graveyard); + struct afs_wb_key *wbk, *tmp; + + /* Discard unused keys */ + spin_lock(&vnode->wb_lock); + + if (!mapping_tagged(&vnode->netfs.inode.i_data, PAGECACHE_TAG_WRITEBACK) && + !mapping_tagged(&vnode->netfs.inode.i_data, PAGECACHE_TAG_DIRTY)) { + list_for_each_entry_safe(wbk, tmp, &vnode->wb_keys, vnode_link) { + if (refcount_read(&wbk->usage) == 1) + list_move(&wbk->vnode_link, &graveyard); + } + } + + spin_unlock(&vnode->wb_lock); + + while (!list_empty(&graveyard)) { + wbk = list_entry(graveyard.next, struct afs_wb_key, vnode_link); + list_del(&wbk->vnode_link); + afs_put_wb_key(wbk); + } +} + +/* + * Clean up a page during invalidation. + */ +int afs_launder_folio(struct folio *folio) +{ + struct afs_vnode *vnode = AFS_FS_I(folio_inode(folio)); + struct iov_iter iter; + struct bio_vec bv[1]; + unsigned long priv; + unsigned int f, t; + int ret = 0; + + _enter("{%lx}", folio->index); + + priv = (unsigned long)folio_get_private(folio); + if (folio_clear_dirty_for_io(folio)) { + f = 0; + t = folio_size(folio); + if (folio_test_private(folio)) { + f = afs_folio_dirty_from(folio, priv); + t = afs_folio_dirty_to(folio, priv); + } + + bv[0].bv_page = &folio->page; + bv[0].bv_offset = f; + bv[0].bv_len = t - f; + iov_iter_bvec(&iter, ITER_SOURCE, bv, 1, bv[0].bv_len); + + trace_afs_folio_dirty(vnode, tracepoint_string("launder"), folio); + ret = afs_store_data(vnode, &iter, folio_pos(folio) + f, true); + } + + trace_afs_folio_dirty(vnode, tracepoint_string("laundered"), folio); + folio_detach_private(folio); + folio_wait_fscache(folio); + return ret; +} + +/* + * Deal with the completion of writing the data to the cache. + */ +static void afs_write_to_cache_done(void *priv, ssize_t transferred_or_error, + bool was_async) +{ + struct afs_vnode *vnode = priv; + + if (IS_ERR_VALUE(transferred_or_error) && + transferred_or_error != -ENOBUFS) + afs_invalidate_cache(vnode, 0); +} + +/* + * Save the write to the cache also. + */ +static void afs_write_to_cache(struct afs_vnode *vnode, + loff_t start, size_t len, loff_t i_size, + bool caching) +{ + fscache_write_to_cache(afs_vnode_cache(vnode), + vnode->netfs.inode.i_mapping, start, len, i_size, + afs_write_to_cache_done, vnode, caching); +} |