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-rw-r--r--fs/afs/write.c1054
1 files changed, 1054 insertions, 0 deletions
diff --git a/fs/afs/write.c b/fs/afs/write.c
new file mode 100644
index 0000000000..e1c4534171
--- /dev/null
+++ b/fs/afs/write.c
@@ -0,0 +1,1054 @@
+// 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 int afs_writepages_region(struct address_space *mapping,
+ struct writeback_control *wbc,
+ loff_t start, loff_t end, loff_t *_next,
+ bool max_one_loop);
+
+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
+
+/*
+ * Flush out a conflicting write. This may extend the write to the surrounding
+ * pages if also dirty and contiguous to the conflicting region..
+ */
+static int afs_flush_conflicting_write(struct address_space *mapping,
+ struct folio *folio)
+{
+ struct writeback_control wbc = {
+ .sync_mode = WB_SYNC_ALL,
+ .nr_to_write = LONG_MAX,
+ .range_start = folio_pos(folio),
+ .range_end = LLONG_MAX,
+ };
+ loff_t next;
+
+ return afs_writepages_region(mapping, &wbc, folio_pos(folio), LLONG_MAX,
+ &next, true);
+}
+
+/*
+ * 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);
+ folio_unlock(folio);
+ goto wait_for_writeback;
+ }
+ /* 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:
+ trace_afs_folio_dirty(vnode, tracepoint_string("confl"), folio);
+ folio_unlock(folio);
+
+ ret = afs_flush_conflicting_write(mapping, folio);
+ if (ret < 0)
+ goto error;
+
+wait_for_writeback:
+ ret = folio_wait_writeback_killable(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 (IS_ERR(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 (IS_ERR(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 folio_batch fbatch;
+ 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);
+ folio_batch_init(&fbatch);
+
+ 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 (!folio_batch_add(&fbatch, folio))
+ break;
+ if (stop)
+ break;
+ }
+
+ if (!stop)
+ xas_pause(&xas);
+ rcu_read_unlock();
+
+ /* Now, if we obtained any folios, we can shift them to being
+ * writable and mark them for caching.
+ */
+ if (!folio_batch_count(&fbatch))
+ break;
+
+ for (i = 0; i < folio_batch_count(&fbatch); i++) {
+ folio = fbatch.folios[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);
+ }
+
+ folio_batch_release(&fbatch);
+ 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 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,
+ bool max_one_loop)
+{
+ struct folio *folio;
+ struct folio_batch fbatch;
+ ssize_t ret;
+ unsigned int i;
+ int n, skips = 0;
+
+ _enter("%llx,%llx,", start, end);
+ folio_batch_init(&fbatch);
+
+ do {
+ pgoff_t index = start / PAGE_SIZE;
+
+ n = filemap_get_folios_tag(mapping, &index, end / PAGE_SIZE,
+ PAGECACHE_TAG_DIRTY, &fbatch);
+
+ if (!n)
+ break;
+ for (i = 0; i < n; i++) {
+ folio = fbatch.folios[i];
+ 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
+ */
+try_again:
+ if (wbc->sync_mode != WB_SYNC_NONE) {
+ ret = folio_lock_killable(folio);
+ if (ret < 0) {
+ folio_batch_release(&fbatch);
+ return ret;
+ }
+ } else {
+ if (!folio_trylock(folio))
+ continue;
+ }
+
+ if (folio->mapping != mapping ||
+ !folio_test_dirty(folio)) {
+ start += folio_size(folio);
+ folio_unlock(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
+ goto try_again;
+ }
+
+ start += folio_size(folio);
+ if (wbc->sync_mode == WB_SYNC_NONE) {
+ if (skips >= 5 || need_resched()) {
+ *_next = start;
+ folio_batch_release(&fbatch);
+ _leave(" = 0 [%llx]", *_next);
+ return 0;
+ }
+ skips++;
+ }
+ continue;
+ }
+
+ if (!folio_clear_dirty_for_io(folio))
+ BUG();
+ ret = afs_write_back_from_locked_folio(mapping, wbc,
+ folio, start, end);
+ if (ret < 0) {
+ _leave(" = %zd", ret);
+ folio_batch_release(&fbatch);
+ return ret;
+ }
+
+ start += ret;
+ }
+
+ folio_batch_release(&fbatch);
+ 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, false);
+ 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, false);
+ 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, false);
+ 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, false);
+ }
+
+ 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;
+ 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);
+ }
+
+ bvec_set_folio(&bv, folio, t - f, f);
+ iov_iter_bvec(&iter, ITER_SOURCE, &bv, 1, bv.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);
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-04 23:17:19 +0000