summaryrefslogtreecommitdiffstats
path: root/fs/afs/file.c
diff options
context:
space:
mode:
Diffstat (limited to 'fs/afs/file.c')
-rw-r--r--fs/afs/file.c598
1 files changed, 598 insertions, 0 deletions
diff --git a/fs/afs/file.c b/fs/afs/file.c
new file mode 100644
index 000000000..2eeab57df
--- /dev/null
+++ b/fs/afs/file.c
@@ -0,0 +1,598 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* AFS filesystem file handling
+ *
+ * Copyright (C) 2002, 2007 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/fs.h>
+#include <linux/pagemap.h>
+#include <linux/writeback.h>
+#include <linux/gfp.h>
+#include <linux/task_io_accounting_ops.h>
+#include <linux/mm.h>
+#include <linux/swap.h>
+#include <linux/netfs.h>
+#include "internal.h"
+
+static int afs_file_mmap(struct file *file, struct vm_area_struct *vma);
+static int afs_symlink_read_folio(struct file *file, struct folio *folio);
+static void afs_invalidate_folio(struct folio *folio, size_t offset,
+ size_t length);
+static bool afs_release_folio(struct folio *folio, gfp_t gfp_flags);
+
+static ssize_t afs_file_read_iter(struct kiocb *iocb, struct iov_iter *iter);
+static void afs_vm_open(struct vm_area_struct *area);
+static void afs_vm_close(struct vm_area_struct *area);
+static vm_fault_t afs_vm_map_pages(struct vm_fault *vmf, pgoff_t start_pgoff, pgoff_t end_pgoff);
+
+const struct file_operations afs_file_operations = {
+ .open = afs_open,
+ .release = afs_release,
+ .llseek = generic_file_llseek,
+ .read_iter = afs_file_read_iter,
+ .write_iter = afs_file_write,
+ .mmap = afs_file_mmap,
+ .splice_read = generic_file_splice_read,
+ .splice_write = iter_file_splice_write,
+ .fsync = afs_fsync,
+ .lock = afs_lock,
+ .flock = afs_flock,
+};
+
+const struct inode_operations afs_file_inode_operations = {
+ .getattr = afs_getattr,
+ .setattr = afs_setattr,
+ .permission = afs_permission,
+};
+
+const struct address_space_operations afs_file_aops = {
+ .read_folio = netfs_read_folio,
+ .readahead = netfs_readahead,
+ .dirty_folio = afs_dirty_folio,
+ .launder_folio = afs_launder_folio,
+ .release_folio = afs_release_folio,
+ .invalidate_folio = afs_invalidate_folio,
+ .write_begin = afs_write_begin,
+ .write_end = afs_write_end,
+ .writepage = afs_writepage,
+ .writepages = afs_writepages,
+};
+
+const struct address_space_operations afs_symlink_aops = {
+ .read_folio = afs_symlink_read_folio,
+ .release_folio = afs_release_folio,
+ .invalidate_folio = afs_invalidate_folio,
+};
+
+static const struct vm_operations_struct afs_vm_ops = {
+ .open = afs_vm_open,
+ .close = afs_vm_close,
+ .fault = filemap_fault,
+ .map_pages = afs_vm_map_pages,
+ .page_mkwrite = afs_page_mkwrite,
+};
+
+/*
+ * Discard a pin on a writeback key.
+ */
+void afs_put_wb_key(struct afs_wb_key *wbk)
+{
+ if (wbk && refcount_dec_and_test(&wbk->usage)) {
+ key_put(wbk->key);
+ kfree(wbk);
+ }
+}
+
+/*
+ * Cache key for writeback.
+ */
+int afs_cache_wb_key(struct afs_vnode *vnode, struct afs_file *af)
+{
+ struct afs_wb_key *wbk, *p;
+
+ wbk = kzalloc(sizeof(struct afs_wb_key), GFP_KERNEL);
+ if (!wbk)
+ return -ENOMEM;
+ refcount_set(&wbk->usage, 2);
+ wbk->key = af->key;
+
+ spin_lock(&vnode->wb_lock);
+ list_for_each_entry(p, &vnode->wb_keys, vnode_link) {
+ if (p->key == wbk->key)
+ goto found;
+ }
+
+ key_get(wbk->key);
+ list_add_tail(&wbk->vnode_link, &vnode->wb_keys);
+ spin_unlock(&vnode->wb_lock);
+ af->wb = wbk;
+ return 0;
+
+found:
+ refcount_inc(&p->usage);
+ spin_unlock(&vnode->wb_lock);
+ af->wb = p;
+ kfree(wbk);
+ return 0;
+}
+
+/*
+ * open an AFS file or directory and attach a key to it
+ */
+int afs_open(struct inode *inode, struct file *file)
+{
+ struct afs_vnode *vnode = AFS_FS_I(inode);
+ struct afs_file *af;
+ struct key *key;
+ int ret;
+
+ _enter("{%llx:%llu},", vnode->fid.vid, vnode->fid.vnode);
+
+ key = afs_request_key(vnode->volume->cell);
+ if (IS_ERR(key)) {
+ ret = PTR_ERR(key);
+ goto error;
+ }
+
+ af = kzalloc(sizeof(*af), GFP_KERNEL);
+ if (!af) {
+ ret = -ENOMEM;
+ goto error_key;
+ }
+ af->key = key;
+
+ ret = afs_validate(vnode, key);
+ if (ret < 0)
+ goto error_af;
+
+ if (file->f_mode & FMODE_WRITE) {
+ ret = afs_cache_wb_key(vnode, af);
+ if (ret < 0)
+ goto error_af;
+ }
+
+ if (file->f_flags & O_TRUNC)
+ set_bit(AFS_VNODE_NEW_CONTENT, &vnode->flags);
+
+ fscache_use_cookie(afs_vnode_cache(vnode), file->f_mode & FMODE_WRITE);
+
+ file->private_data = af;
+ _leave(" = 0");
+ return 0;
+
+error_af:
+ kfree(af);
+error_key:
+ key_put(key);
+error:
+ _leave(" = %d", ret);
+ return ret;
+}
+
+/*
+ * release an AFS file or directory and discard its key
+ */
+int afs_release(struct inode *inode, struct file *file)
+{
+ struct afs_vnode_cache_aux aux;
+ struct afs_vnode *vnode = AFS_FS_I(inode);
+ struct afs_file *af = file->private_data;
+ loff_t i_size;
+ int ret = 0;
+
+ _enter("{%llx:%llu},", vnode->fid.vid, vnode->fid.vnode);
+
+ if ((file->f_mode & FMODE_WRITE))
+ ret = vfs_fsync(file, 0);
+
+ file->private_data = NULL;
+ if (af->wb)
+ afs_put_wb_key(af->wb);
+
+ if ((file->f_mode & FMODE_WRITE)) {
+ i_size = i_size_read(&vnode->netfs.inode);
+ afs_set_cache_aux(vnode, &aux);
+ fscache_unuse_cookie(afs_vnode_cache(vnode), &aux, &i_size);
+ } else {
+ fscache_unuse_cookie(afs_vnode_cache(vnode), NULL, NULL);
+ }
+
+ key_put(af->key);
+ kfree(af);
+ afs_prune_wb_keys(vnode);
+ _leave(" = %d", ret);
+ return ret;
+}
+
+/*
+ * Allocate a new read record.
+ */
+struct afs_read *afs_alloc_read(gfp_t gfp)
+{
+ struct afs_read *req;
+
+ req = kzalloc(sizeof(struct afs_read), gfp);
+ if (req)
+ refcount_set(&req->usage, 1);
+
+ return req;
+}
+
+/*
+ * Dispose of a ref to a read record.
+ */
+void afs_put_read(struct afs_read *req)
+{
+ if (refcount_dec_and_test(&req->usage)) {
+ if (req->cleanup)
+ req->cleanup(req);
+ key_put(req->key);
+ kfree(req);
+ }
+}
+
+static void afs_fetch_data_notify(struct afs_operation *op)
+{
+ struct afs_read *req = op->fetch.req;
+ struct netfs_io_subrequest *subreq = req->subreq;
+ int error = op->error;
+
+ if (error == -ECONNABORTED)
+ error = afs_abort_to_error(op->ac.abort_code);
+ req->error = error;
+
+ if (subreq) {
+ __set_bit(NETFS_SREQ_CLEAR_TAIL, &subreq->flags);
+ netfs_subreq_terminated(subreq, error ?: req->actual_len, false);
+ req->subreq = NULL;
+ } else if (req->done) {
+ req->done(req);
+ }
+}
+
+static void afs_fetch_data_success(struct afs_operation *op)
+{
+ struct afs_vnode *vnode = op->file[0].vnode;
+
+ _enter("op=%08x", op->debug_id);
+ afs_vnode_commit_status(op, &op->file[0]);
+ afs_stat_v(vnode, n_fetches);
+ atomic_long_add(op->fetch.req->actual_len, &op->net->n_fetch_bytes);
+ afs_fetch_data_notify(op);
+}
+
+static void afs_fetch_data_put(struct afs_operation *op)
+{
+ op->fetch.req->error = op->error;
+ afs_put_read(op->fetch.req);
+}
+
+static const struct afs_operation_ops afs_fetch_data_operation = {
+ .issue_afs_rpc = afs_fs_fetch_data,
+ .issue_yfs_rpc = yfs_fs_fetch_data,
+ .success = afs_fetch_data_success,
+ .aborted = afs_check_for_remote_deletion,
+ .failed = afs_fetch_data_notify,
+ .put = afs_fetch_data_put,
+};
+
+/*
+ * Fetch file data from the volume.
+ */
+int afs_fetch_data(struct afs_vnode *vnode, struct afs_read *req)
+{
+ struct afs_operation *op;
+
+ _enter("%s{%llx:%llu.%u},%x,,,",
+ vnode->volume->name,
+ vnode->fid.vid,
+ vnode->fid.vnode,
+ vnode->fid.unique,
+ key_serial(req->key));
+
+ op = afs_alloc_operation(req->key, vnode->volume);
+ if (IS_ERR(op)) {
+ if (req->subreq)
+ netfs_subreq_terminated(req->subreq, PTR_ERR(op), false);
+ return PTR_ERR(op);
+ }
+
+ afs_op_set_vnode(op, 0, vnode);
+
+ op->fetch.req = afs_get_read(req);
+ op->ops = &afs_fetch_data_operation;
+ return afs_do_sync_operation(op);
+}
+
+static void afs_issue_read(struct netfs_io_subrequest *subreq)
+{
+ struct afs_vnode *vnode = AFS_FS_I(subreq->rreq->inode);
+ struct afs_read *fsreq;
+
+ fsreq = afs_alloc_read(GFP_NOFS);
+ if (!fsreq)
+ return netfs_subreq_terminated(subreq, -ENOMEM, false);
+
+ fsreq->subreq = subreq;
+ fsreq->pos = subreq->start + subreq->transferred;
+ fsreq->len = subreq->len - subreq->transferred;
+ fsreq->key = key_get(subreq->rreq->netfs_priv);
+ fsreq->vnode = vnode;
+ fsreq->iter = &fsreq->def_iter;
+
+ iov_iter_xarray(&fsreq->def_iter, ITER_DEST,
+ &fsreq->vnode->netfs.inode.i_mapping->i_pages,
+ fsreq->pos, fsreq->len);
+
+ afs_fetch_data(fsreq->vnode, fsreq);
+ afs_put_read(fsreq);
+}
+
+static int afs_symlink_read_folio(struct file *file, struct folio *folio)
+{
+ struct afs_vnode *vnode = AFS_FS_I(folio->mapping->host);
+ struct afs_read *fsreq;
+ int ret;
+
+ fsreq = afs_alloc_read(GFP_NOFS);
+ if (!fsreq)
+ return -ENOMEM;
+
+ fsreq->pos = folio_pos(folio);
+ fsreq->len = folio_size(folio);
+ fsreq->vnode = vnode;
+ fsreq->iter = &fsreq->def_iter;
+ iov_iter_xarray(&fsreq->def_iter, ITER_DEST, &folio->mapping->i_pages,
+ fsreq->pos, fsreq->len);
+
+ ret = afs_fetch_data(fsreq->vnode, fsreq);
+ if (ret == 0)
+ folio_mark_uptodate(folio);
+ folio_unlock(folio);
+ return ret;
+}
+
+static int afs_init_request(struct netfs_io_request *rreq, struct file *file)
+{
+ rreq->netfs_priv = key_get(afs_file_key(file));
+ return 0;
+}
+
+static int afs_begin_cache_operation(struct netfs_io_request *rreq)
+{
+#ifdef CONFIG_AFS_FSCACHE
+ struct afs_vnode *vnode = AFS_FS_I(rreq->inode);
+
+ return fscache_begin_read_operation(&rreq->cache_resources,
+ afs_vnode_cache(vnode));
+#else
+ return -ENOBUFS;
+#endif
+}
+
+static int afs_check_write_begin(struct file *file, loff_t pos, unsigned len,
+ struct folio **foliop, void **_fsdata)
+{
+ struct afs_vnode *vnode = AFS_FS_I(file_inode(file));
+
+ return test_bit(AFS_VNODE_DELETED, &vnode->flags) ? -ESTALE : 0;
+}
+
+static void afs_free_request(struct netfs_io_request *rreq)
+{
+ key_put(rreq->netfs_priv);
+}
+
+const struct netfs_request_ops afs_req_ops = {
+ .init_request = afs_init_request,
+ .free_request = afs_free_request,
+ .begin_cache_operation = afs_begin_cache_operation,
+ .check_write_begin = afs_check_write_begin,
+ .issue_read = afs_issue_read,
+};
+
+int afs_write_inode(struct inode *inode, struct writeback_control *wbc)
+{
+ fscache_unpin_writeback(wbc, afs_vnode_cache(AFS_FS_I(inode)));
+ return 0;
+}
+
+/*
+ * Adjust the dirty region of the page on truncation or full invalidation,
+ * getting rid of the markers altogether if the region is entirely invalidated.
+ */
+static void afs_invalidate_dirty(struct folio *folio, size_t offset,
+ size_t length)
+{
+ struct afs_vnode *vnode = AFS_FS_I(folio_inode(folio));
+ unsigned long priv;
+ unsigned int f, t, end = offset + length;
+
+ priv = (unsigned long)folio_get_private(folio);
+
+ /* we clean up only if the entire page is being invalidated */
+ if (offset == 0 && length == folio_size(folio))
+ goto full_invalidate;
+
+ /* If the page was dirtied by page_mkwrite(), the PTE stays writable
+ * and we don't get another notification to tell us to expand it
+ * again.
+ */
+ if (afs_is_folio_dirty_mmapped(priv))
+ return;
+
+ /* We may need to shorten the dirty region */
+ f = afs_folio_dirty_from(folio, priv);
+ t = afs_folio_dirty_to(folio, priv);
+
+ if (t <= offset || f >= end)
+ return; /* Doesn't overlap */
+
+ if (f < offset && t > end)
+ return; /* Splits the dirty region - just absorb it */
+
+ if (f >= offset && t <= end)
+ goto undirty;
+
+ if (f < offset)
+ t = offset;
+ else
+ f = end;
+ if (f == t)
+ goto undirty;
+
+ priv = afs_folio_dirty(folio, f, t);
+ folio_change_private(folio, (void *)priv);
+ trace_afs_folio_dirty(vnode, tracepoint_string("trunc"), folio);
+ return;
+
+undirty:
+ trace_afs_folio_dirty(vnode, tracepoint_string("undirty"), folio);
+ folio_clear_dirty_for_io(folio);
+full_invalidate:
+ trace_afs_folio_dirty(vnode, tracepoint_string("inval"), folio);
+ folio_detach_private(folio);
+}
+
+/*
+ * invalidate part or all of a page
+ * - release a page and clean up its private data if offset is 0 (indicating
+ * the entire page)
+ */
+static void afs_invalidate_folio(struct folio *folio, size_t offset,
+ size_t length)
+{
+ _enter("{%lu},%zu,%zu", folio->index, offset, length);
+
+ BUG_ON(!folio_test_locked(folio));
+
+ if (folio_get_private(folio))
+ afs_invalidate_dirty(folio, offset, length);
+
+ folio_wait_fscache(folio);
+ _leave("");
+}
+
+/*
+ * release a page and clean up its private state if it's not busy
+ * - return true if the page can now be released, false if not
+ */
+static bool afs_release_folio(struct folio *folio, gfp_t gfp)
+{
+ struct afs_vnode *vnode = AFS_FS_I(folio_inode(folio));
+
+ _enter("{{%llx:%llu}[%lu],%lx},%x",
+ vnode->fid.vid, vnode->fid.vnode, folio_index(folio), folio->flags,
+ gfp);
+
+ /* deny if folio is being written to the cache and the caller hasn't
+ * elected to wait */
+#ifdef CONFIG_AFS_FSCACHE
+ if (folio_test_fscache(folio)) {
+ if (current_is_kswapd() || !(gfp & __GFP_FS))
+ return false;
+ folio_wait_fscache(folio);
+ }
+ fscache_note_page_release(afs_vnode_cache(vnode));
+#endif
+
+ if (folio_test_private(folio)) {
+ trace_afs_folio_dirty(vnode, tracepoint_string("rel"), folio);
+ folio_detach_private(folio);
+ }
+
+ /* Indicate that the folio can be released */
+ _leave(" = T");
+ return true;
+}
+
+static void afs_add_open_mmap(struct afs_vnode *vnode)
+{
+ if (atomic_inc_return(&vnode->cb_nr_mmap) == 1) {
+ down_write(&vnode->volume->cell->fs_open_mmaps_lock);
+
+ if (list_empty(&vnode->cb_mmap_link))
+ list_add_tail(&vnode->cb_mmap_link,
+ &vnode->volume->cell->fs_open_mmaps);
+
+ up_write(&vnode->volume->cell->fs_open_mmaps_lock);
+ }
+}
+
+static void afs_drop_open_mmap(struct afs_vnode *vnode)
+{
+ if (!atomic_dec_and_test(&vnode->cb_nr_mmap))
+ return;
+
+ down_write(&vnode->volume->cell->fs_open_mmaps_lock);
+
+ if (atomic_read(&vnode->cb_nr_mmap) == 0)
+ list_del_init(&vnode->cb_mmap_link);
+
+ up_write(&vnode->volume->cell->fs_open_mmaps_lock);
+ flush_work(&vnode->cb_work);
+}
+
+/*
+ * Handle setting up a memory mapping on an AFS file.
+ */
+static int afs_file_mmap(struct file *file, struct vm_area_struct *vma)
+{
+ struct afs_vnode *vnode = AFS_FS_I(file_inode(file));
+ int ret;
+
+ afs_add_open_mmap(vnode);
+
+ ret = generic_file_mmap(file, vma);
+ if (ret == 0)
+ vma->vm_ops = &afs_vm_ops;
+ else
+ afs_drop_open_mmap(vnode);
+ return ret;
+}
+
+static void afs_vm_open(struct vm_area_struct *vma)
+{
+ afs_add_open_mmap(AFS_FS_I(file_inode(vma->vm_file)));
+}
+
+static void afs_vm_close(struct vm_area_struct *vma)
+{
+ afs_drop_open_mmap(AFS_FS_I(file_inode(vma->vm_file)));
+}
+
+static vm_fault_t afs_vm_map_pages(struct vm_fault *vmf, pgoff_t start_pgoff, pgoff_t end_pgoff)
+{
+ struct afs_vnode *vnode = AFS_FS_I(file_inode(vmf->vma->vm_file));
+ struct afs_file *af = vmf->vma->vm_file->private_data;
+
+ switch (afs_validate(vnode, af->key)) {
+ case 0:
+ return filemap_map_pages(vmf, start_pgoff, end_pgoff);
+ case -ENOMEM:
+ return VM_FAULT_OOM;
+ case -EINTR:
+ case -ERESTARTSYS:
+ return VM_FAULT_RETRY;
+ case -ESTALE:
+ default:
+ return VM_FAULT_SIGBUS;
+ }
+}
+
+static ssize_t afs_file_read_iter(struct kiocb *iocb, struct iov_iter *iter)
+{
+ struct afs_vnode *vnode = AFS_FS_I(file_inode(iocb->ki_filp));
+ struct afs_file *af = iocb->ki_filp->private_data;
+ int ret;
+
+ ret = afs_validate(vnode, af->key);
+ if (ret < 0)
+ return ret;
+
+ return generic_file_read_iter(iocb, iter);
+}