linuxdebug/fs/afs/file.c

599 lines
14 KiB
C
Raw Permalink Normal View History

2024-07-16 15:50:57 +02:00
// 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);
}