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![Matthew Wilcox (Oracle)](/assets/img/avatar_default.png)
For the map_pages() method, we need a test that does not sleep. The page fault handler will continue to call the fault() method where we can sleep and do the full revalidation there. Link: https://lkml.kernel.org/r/20230327174515.1811532-3-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Acked-by: David Howells <dhowells@redhat.com> Tested-by: David Howells <dhowells@redhat.com> Cc: Darrick J. Wong <djwong@kernel.org> Cc: Dave Chinner <david@fromorbit.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
589 lines
14 KiB
C
589 lines
14 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/* AFS filesystem file handling
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*
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* Copyright (C) 2002, 2007 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/fs.h>
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#include <linux/pagemap.h>
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#include <linux/writeback.h>
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#include <linux/gfp.h>
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#include <linux/task_io_accounting_ops.h>
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#include <linux/mm.h>
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#include <linux/swap.h>
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#include <linux/netfs.h>
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#include "internal.h"
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static int afs_file_mmap(struct file *file, struct vm_area_struct *vma);
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static int afs_symlink_read_folio(struct file *file, struct folio *folio);
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static void afs_invalidate_folio(struct folio *folio, size_t offset,
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size_t length);
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static bool afs_release_folio(struct folio *folio, gfp_t gfp_flags);
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static ssize_t afs_file_read_iter(struct kiocb *iocb, struct iov_iter *iter);
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static void afs_vm_open(struct vm_area_struct *area);
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static void afs_vm_close(struct vm_area_struct *area);
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static vm_fault_t afs_vm_map_pages(struct vm_fault *vmf, pgoff_t start_pgoff, pgoff_t end_pgoff);
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const struct file_operations afs_file_operations = {
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.open = afs_open,
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.release = afs_release,
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.llseek = generic_file_llseek,
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.read_iter = afs_file_read_iter,
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.write_iter = afs_file_write,
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.mmap = afs_file_mmap,
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.splice_read = generic_file_splice_read,
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.splice_write = iter_file_splice_write,
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.fsync = afs_fsync,
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.lock = afs_lock,
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.flock = afs_flock,
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};
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const struct inode_operations afs_file_inode_operations = {
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.getattr = afs_getattr,
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.setattr = afs_setattr,
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.permission = afs_permission,
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};
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const struct address_space_operations afs_file_aops = {
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.read_folio = netfs_read_folio,
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.readahead = netfs_readahead,
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.dirty_folio = afs_dirty_folio,
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.launder_folio = afs_launder_folio,
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.release_folio = afs_release_folio,
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.invalidate_folio = afs_invalidate_folio,
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.write_begin = afs_write_begin,
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.write_end = afs_write_end,
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.writepages = afs_writepages,
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.migrate_folio = filemap_migrate_folio,
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};
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const struct address_space_operations afs_symlink_aops = {
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.read_folio = afs_symlink_read_folio,
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.release_folio = afs_release_folio,
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.invalidate_folio = afs_invalidate_folio,
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.migrate_folio = filemap_migrate_folio,
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};
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static const struct vm_operations_struct afs_vm_ops = {
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.open = afs_vm_open,
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.close = afs_vm_close,
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.fault = filemap_fault,
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.map_pages = afs_vm_map_pages,
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.page_mkwrite = afs_page_mkwrite,
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};
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/*
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* Discard a pin on a writeback key.
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*/
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void afs_put_wb_key(struct afs_wb_key *wbk)
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{
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if (wbk && refcount_dec_and_test(&wbk->usage)) {
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key_put(wbk->key);
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kfree(wbk);
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}
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}
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/*
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* Cache key for writeback.
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*/
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int afs_cache_wb_key(struct afs_vnode *vnode, struct afs_file *af)
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{
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struct afs_wb_key *wbk, *p;
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wbk = kzalloc(sizeof(struct afs_wb_key), GFP_KERNEL);
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if (!wbk)
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return -ENOMEM;
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refcount_set(&wbk->usage, 2);
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wbk->key = af->key;
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spin_lock(&vnode->wb_lock);
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list_for_each_entry(p, &vnode->wb_keys, vnode_link) {
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if (p->key == wbk->key)
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goto found;
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}
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key_get(wbk->key);
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list_add_tail(&wbk->vnode_link, &vnode->wb_keys);
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spin_unlock(&vnode->wb_lock);
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af->wb = wbk;
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return 0;
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found:
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refcount_inc(&p->usage);
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spin_unlock(&vnode->wb_lock);
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af->wb = p;
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kfree(wbk);
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return 0;
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}
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/*
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* open an AFS file or directory and attach a key to it
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*/
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int afs_open(struct inode *inode, struct file *file)
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{
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struct afs_vnode *vnode = AFS_FS_I(inode);
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struct afs_file *af;
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struct key *key;
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int ret;
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_enter("{%llx:%llu},", vnode->fid.vid, vnode->fid.vnode);
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key = afs_request_key(vnode->volume->cell);
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if (IS_ERR(key)) {
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ret = PTR_ERR(key);
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goto error;
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}
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af = kzalloc(sizeof(*af), GFP_KERNEL);
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if (!af) {
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ret = -ENOMEM;
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goto error_key;
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}
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af->key = key;
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ret = afs_validate(vnode, key);
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if (ret < 0)
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goto error_af;
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if (file->f_mode & FMODE_WRITE) {
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ret = afs_cache_wb_key(vnode, af);
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if (ret < 0)
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goto error_af;
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}
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if (file->f_flags & O_TRUNC)
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set_bit(AFS_VNODE_NEW_CONTENT, &vnode->flags);
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fscache_use_cookie(afs_vnode_cache(vnode), file->f_mode & FMODE_WRITE);
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file->private_data = af;
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_leave(" = 0");
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return 0;
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error_af:
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kfree(af);
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error_key:
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key_put(key);
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error:
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_leave(" = %d", ret);
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return ret;
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}
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/*
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* release an AFS file or directory and discard its key
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*/
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int afs_release(struct inode *inode, struct file *file)
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{
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struct afs_vnode_cache_aux aux;
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struct afs_vnode *vnode = AFS_FS_I(inode);
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struct afs_file *af = file->private_data;
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loff_t i_size;
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int ret = 0;
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_enter("{%llx:%llu},", vnode->fid.vid, vnode->fid.vnode);
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if ((file->f_mode & FMODE_WRITE))
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ret = vfs_fsync(file, 0);
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file->private_data = NULL;
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if (af->wb)
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afs_put_wb_key(af->wb);
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if ((file->f_mode & FMODE_WRITE)) {
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i_size = i_size_read(&vnode->netfs.inode);
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afs_set_cache_aux(vnode, &aux);
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fscache_unuse_cookie(afs_vnode_cache(vnode), &aux, &i_size);
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} else {
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fscache_unuse_cookie(afs_vnode_cache(vnode), NULL, NULL);
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}
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key_put(af->key);
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kfree(af);
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afs_prune_wb_keys(vnode);
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_leave(" = %d", ret);
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return ret;
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}
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/*
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* Allocate a new read record.
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*/
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struct afs_read *afs_alloc_read(gfp_t gfp)
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{
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struct afs_read *req;
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req = kzalloc(sizeof(struct afs_read), gfp);
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if (req)
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refcount_set(&req->usage, 1);
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return req;
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}
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/*
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* Dispose of a ref to a read record.
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*/
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void afs_put_read(struct afs_read *req)
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{
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if (refcount_dec_and_test(&req->usage)) {
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if (req->cleanup)
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req->cleanup(req);
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key_put(req->key);
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kfree(req);
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}
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}
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static void afs_fetch_data_notify(struct afs_operation *op)
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{
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struct afs_read *req = op->fetch.req;
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struct netfs_io_subrequest *subreq = req->subreq;
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int error = op->error;
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if (error == -ECONNABORTED)
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error = afs_abort_to_error(op->ac.abort_code);
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req->error = error;
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if (subreq) {
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__set_bit(NETFS_SREQ_CLEAR_TAIL, &subreq->flags);
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netfs_subreq_terminated(subreq, error ?: req->actual_len, false);
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req->subreq = NULL;
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} else if (req->done) {
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req->done(req);
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}
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}
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static void afs_fetch_data_success(struct afs_operation *op)
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{
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struct afs_vnode *vnode = op->file[0].vnode;
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_enter("op=%08x", op->debug_id);
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afs_vnode_commit_status(op, &op->file[0]);
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afs_stat_v(vnode, n_fetches);
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atomic_long_add(op->fetch.req->actual_len, &op->net->n_fetch_bytes);
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afs_fetch_data_notify(op);
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}
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static void afs_fetch_data_put(struct afs_operation *op)
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{
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op->fetch.req->error = op->error;
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afs_put_read(op->fetch.req);
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}
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static const struct afs_operation_ops afs_fetch_data_operation = {
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.issue_afs_rpc = afs_fs_fetch_data,
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.issue_yfs_rpc = yfs_fs_fetch_data,
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.success = afs_fetch_data_success,
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.aborted = afs_check_for_remote_deletion,
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.failed = afs_fetch_data_notify,
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.put = afs_fetch_data_put,
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};
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/*
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* Fetch file data from the volume.
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*/
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int afs_fetch_data(struct afs_vnode *vnode, struct afs_read *req)
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{
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struct afs_operation *op;
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_enter("%s{%llx:%llu.%u},%x,,,",
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vnode->volume->name,
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vnode->fid.vid,
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vnode->fid.vnode,
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vnode->fid.unique,
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key_serial(req->key));
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op = afs_alloc_operation(req->key, vnode->volume);
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if (IS_ERR(op)) {
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if (req->subreq)
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netfs_subreq_terminated(req->subreq, PTR_ERR(op), false);
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return PTR_ERR(op);
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}
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afs_op_set_vnode(op, 0, vnode);
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op->fetch.req = afs_get_read(req);
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op->ops = &afs_fetch_data_operation;
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return afs_do_sync_operation(op);
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}
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static void afs_issue_read(struct netfs_io_subrequest *subreq)
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{
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struct afs_vnode *vnode = AFS_FS_I(subreq->rreq->inode);
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struct afs_read *fsreq;
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fsreq = afs_alloc_read(GFP_NOFS);
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if (!fsreq)
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return netfs_subreq_terminated(subreq, -ENOMEM, false);
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fsreq->subreq = subreq;
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fsreq->pos = subreq->start + subreq->transferred;
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fsreq->len = subreq->len - subreq->transferred;
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fsreq->key = key_get(subreq->rreq->netfs_priv);
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fsreq->vnode = vnode;
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fsreq->iter = &fsreq->def_iter;
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iov_iter_xarray(&fsreq->def_iter, ITER_DEST,
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&fsreq->vnode->netfs.inode.i_mapping->i_pages,
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fsreq->pos, fsreq->len);
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afs_fetch_data(fsreq->vnode, fsreq);
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afs_put_read(fsreq);
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}
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static int afs_symlink_read_folio(struct file *file, struct folio *folio)
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{
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struct afs_vnode *vnode = AFS_FS_I(folio->mapping->host);
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struct afs_read *fsreq;
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int ret;
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fsreq = afs_alloc_read(GFP_NOFS);
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if (!fsreq)
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return -ENOMEM;
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fsreq->pos = folio_pos(folio);
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fsreq->len = folio_size(folio);
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fsreq->vnode = vnode;
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fsreq->iter = &fsreq->def_iter;
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iov_iter_xarray(&fsreq->def_iter, ITER_DEST, &folio->mapping->i_pages,
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fsreq->pos, fsreq->len);
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ret = afs_fetch_data(fsreq->vnode, fsreq);
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if (ret == 0)
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folio_mark_uptodate(folio);
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folio_unlock(folio);
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return ret;
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}
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static int afs_init_request(struct netfs_io_request *rreq, struct file *file)
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{
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rreq->netfs_priv = key_get(afs_file_key(file));
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return 0;
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}
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static int afs_begin_cache_operation(struct netfs_io_request *rreq)
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{
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#ifdef CONFIG_AFS_FSCACHE
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struct afs_vnode *vnode = AFS_FS_I(rreq->inode);
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return fscache_begin_read_operation(&rreq->cache_resources,
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afs_vnode_cache(vnode));
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#else
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return -ENOBUFS;
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#endif
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}
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static int afs_check_write_begin(struct file *file, loff_t pos, unsigned len,
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struct folio **foliop, void **_fsdata)
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{
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struct afs_vnode *vnode = AFS_FS_I(file_inode(file));
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return test_bit(AFS_VNODE_DELETED, &vnode->flags) ? -ESTALE : 0;
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}
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static void afs_free_request(struct netfs_io_request *rreq)
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{
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key_put(rreq->netfs_priv);
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}
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const struct netfs_request_ops afs_req_ops = {
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.init_request = afs_init_request,
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.free_request = afs_free_request,
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.begin_cache_operation = afs_begin_cache_operation,
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.check_write_begin = afs_check_write_begin,
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.issue_read = afs_issue_read,
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};
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int afs_write_inode(struct inode *inode, struct writeback_control *wbc)
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{
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fscache_unpin_writeback(wbc, afs_vnode_cache(AFS_FS_I(inode)));
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return 0;
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}
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/*
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* Adjust the dirty region of the page on truncation or full invalidation,
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* getting rid of the markers altogether if the region is entirely invalidated.
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*/
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static void afs_invalidate_dirty(struct folio *folio, size_t offset,
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size_t length)
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{
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struct afs_vnode *vnode = AFS_FS_I(folio_inode(folio));
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unsigned long priv;
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unsigned int f, t, end = offset + length;
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priv = (unsigned long)folio_get_private(folio);
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/* we clean up only if the entire page is being invalidated */
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if (offset == 0 && length == folio_size(folio))
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goto full_invalidate;
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/* If the page was dirtied by page_mkwrite(), the PTE stays writable
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* and we don't get another notification to tell us to expand it
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* again.
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*/
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if (afs_is_folio_dirty_mmapped(priv))
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return;
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/* We may need to shorten the dirty region */
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f = afs_folio_dirty_from(folio, priv);
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t = afs_folio_dirty_to(folio, priv);
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if (t <= offset || f >= end)
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return; /* Doesn't overlap */
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if (f < offset && t > end)
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return; /* Splits the dirty region - just absorb it */
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if (f >= offset && t <= end)
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goto undirty;
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if (f < offset)
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t = offset;
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else
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f = end;
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if (f == t)
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goto undirty;
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priv = afs_folio_dirty(folio, f, t);
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folio_change_private(folio, (void *)priv);
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trace_afs_folio_dirty(vnode, tracepoint_string("trunc"), folio);
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return;
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undirty:
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trace_afs_folio_dirty(vnode, tracepoint_string("undirty"), folio);
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folio_clear_dirty_for_io(folio);
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full_invalidate:
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trace_afs_folio_dirty(vnode, tracepoint_string("inval"), folio);
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folio_detach_private(folio);
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}
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/*
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* invalidate part or all of a page
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* - release a page and clean up its private data if offset is 0 (indicating
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* the entire page)
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*/
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static void afs_invalidate_folio(struct folio *folio, size_t offset,
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size_t length)
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{
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_enter("{%lu},%zu,%zu", folio->index, offset, length);
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BUG_ON(!folio_test_locked(folio));
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if (folio_get_private(folio))
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afs_invalidate_dirty(folio, offset, length);
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folio_wait_fscache(folio);
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_leave("");
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}
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/*
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* release a page and clean up its private state if it's not busy
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* - return true if the page can now be released, false if not
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*/
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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));
|
|
|
|
if (afs_pagecache_valid(vnode))
|
|
return filemap_map_pages(vmf, start_pgoff, end_pgoff);
|
|
return 0;
|
|
}
|
|
|
|
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);
|
|
}
|