// SPDX-License-Identifier: GPL-2.0
#ifndef NO_BCACHEFS_FS
#include "bcachefs.h"
#include "alloc_foreground.h"
#include "fs.h"
#include "fs-io.h"
#include "fs-io-direct.h"
#include "fs-io-pagecache.h"
#include "io_read.h"
#include "io_write.h"
#include <linux/kthread.h>
#include <linux/pagemap.h>
#include <linux/prefetch.h>
#include <linux/task_io_accounting_ops.h>
/* O_DIRECT reads */
struct dio_read {
struct closure cl;
struct kiocb *req;
long ret;
bool should_dirty;
struct bch_read_bio rbio;
};
static void bio_check_or_release(struct bio *bio, bool check_dirty)
{
if (check_dirty) {
bio_check_pages_dirty(bio);
} else {
bio_release_pages(bio, false);
bio_put(bio);
}
}
static CLOSURE_CALLBACK(bch2_dio_read_complete)
{
closure_type(dio, struct dio_read, cl);
dio->req->ki_complete(dio->req, dio->ret);
bio_check_or_release(&dio->rbio.bio, dio->should_dirty);
}
static void bch2_direct_IO_read_endio(struct bio *bio)
{
struct dio_read *dio = bio->bi_private;
if (bio->bi_status)
dio->ret = blk_status_to_errno(bio->bi_status);
closure_put(&dio->cl);
}
static void bch2_direct_IO_read_split_endio(struct bio *bio)
{
struct dio_read *dio = bio->bi_private;
bool should_dirty = dio->should_dirty;
bch2_direct_IO_read_endio(bio);
bio_check_or_release(bio, should_dirty);
}
static int bch2_direct_IO_read(struct kiocb *req, struct iov_iter *iter)
{
struct file *file = req->ki_filp;
struct bch_inode_info *inode = file_bch_inode(file);
struct bch_fs *c = inode->v.i_sb->s_fs_info;
struct bch_io_opts opts;
struct dio_read *dio;
struct bio *bio;
loff_t offset = req->ki_pos;
bool sync = is_sync_kiocb(req);
size_t shorten;
ssize_t ret;
bch2_inode_opts_get(&opts, c, &inode->ei_inode);
/* bios must be 512 byte aligned: */
if ((offset|iter->count) & (SECTOR_SIZE - 1))
return -EINVAL;
ret = min_t(loff_t, iter->count,
max_t(loff_t, 0, i_size_read(&inode->v) - offset));
if (!ret)
return ret;
shorten = iov_iter_count(iter) - round_up(ret, block_bytes(c));
if (shorten >= iter->count)
shorten = 0;
iter->count -= shorten;
bio = bio_alloc_bioset(NULL,
bio_iov_vecs_to_alloc(iter, BIO_MAX_VECS),
REQ_OP_READ,
GFP_KERNEL,
&c->dio_read_bioset);
bio->bi_end_io = bch2_direct_IO_read_endio;
dio = container_of(bio, struct dio_read, rbio.bio);
closure_init(&dio->cl, NULL);
/*
* this is a _really_ horrible hack just to avoid an atomic sub at the
* end:
*/
if (!sync) {
set_closure_fn(&dio->cl, bch2_dio_read_complete, NULL);
atomic_set(&dio->cl.remaining,
CLOSURE_REMAINING_INITIALIZER -
CLOSURE_RUNNING +
CLOSURE_DESTRUCTOR);
} else {
atomic_set(&dio->cl.remaining,
CLOSURE_REMAINING_INITIALIZER + 1);
dio->cl.closure_get_happened = true;
}
dio->req = req;
dio->ret = ret;
/*
* This is one of the sketchier things I've encountered: we have to skip
* the dirtying of requests that are internal from the kernel (i.e. from
* loopback), because we'll deadlock on page_lock.
*/
dio->should_dirty = iter_is_iovec(iter);
goto start;
while (iter->count) {
bio = bio_alloc_bioset(NULL,
bio_iov_vecs_to_alloc(iter, BIO_MAX_VECS),
REQ_OP_READ,
GFP_KERNEL,
&c->bio_read);
bio->bi_end_io = bch2_direct_IO_read_split_endio;
start:
bio->bi_opf = REQ_OP_READ|REQ_SYNC;
bio->bi_iter.bi_sector = offset >> 9;
bio->bi_private = dio;
ret = bio_iov_iter_get_pages(bio, iter);
if (ret < 0) {
/* XXX: fault inject this path */
bio->bi_status = BLK_STS_RESOURCE;
bio_endio(bio);
break;
}
offset += bio->bi_iter.bi_size;
if (dio->should_dirty)
bio_set_pages_dirty(bio);
if (iter->count)
closure_get(&dio->cl);
bch2_read(c, rbio_init(bio, opts), inode_inum(inode));
}
iter->count += shorten;
if (sync) {
closure_sync(&dio->cl);
closure_debug_destroy(&dio->cl);
ret = dio->ret;
bio_check_or_release(&dio->rbio.bio, dio->should_dirty);
return ret;
} else {
return -EIOCBQUEUED;
}
}
ssize_t bch2_read_iter(struct kiocb *iocb, struct iov_iter *iter)
{
struct file *file = iocb->ki_filp;
struct bch_inode_info *inode = file_bch_inode(file);
struct address_space *mapping = file->f_mapping;
size_t count = iov_iter_count(iter);
ssize_t ret = 0;
if (!count)
return 0; /* skip atime */
if (iocb->ki_flags & IOCB_DIRECT) {
struct blk_plug plug;
if (unlikely(mapping->nrpages)) {
ret = filemap_write_and_wait_range(mapping,
iocb->ki_pos,
iocb->ki_pos + count - 1);
if (ret < 0)
goto out;
}
file_accessed(file);
blk_start_plug(&plug);
ret = bch2_direct_IO_read(iocb, iter);
blk_finish_plug(&plug);
if (ret >= 0)
iocb->ki_pos += ret;
} else {
bch2_pagecache_add_get(inode);
ret = filemap_read(iocb, iter, ret);
bch2_pagecache_add_put(inode);
}
out:
return bch2_err_class(ret);
}
/* O_DIRECT writes */
struct dio_write {
struct kiocb *req;
struct address_space *mapping;
struct bch_inode_info *inode;
struct mm_struct *mm;
const struct iovec *iov;
unsigned loop:1,
extending:1,
sync:1,
flush:1;
struct quota_res quota_res;
u64 written;
struct iov_iter iter;
struct iovec inline_vecs[2];
/* must be last: */
struct bch_write_op op;
};
static bool bch2_check_range_allocated(struct bch_fs *c, subvol_inum inum,
u64 offset, u64 size,
unsigned nr_replicas, bool compressed)
{
struct btree_trans *trans = bch2_trans_get(c);
struct btree_iter iter;
struct bkey_s_c k;
u64 end = offset + size;
u32 snapshot;
bool ret = true;
int err;
retry:
bch2_trans_begin(trans);
err = bch2_subvolume_get_snapshot(trans, inum.subvol, &snapshot);
if (err)
goto err;
for_each_btree_key_norestart(trans, iter, BTREE_ID_extents,
SPOS(inum.inum, offset, snapshot),
BTREE_ITER_slots, k, err) {
if (bkey_ge(bkey_start_pos(k.k), POS(inum.inum, end)))
break;
if (k.k->p.snapshot != snapshot ||
nr_replicas > bch2_bkey_replicas(c, k) ||
(!compressed && bch2_bkey_sectors_compressed(k))) {
ret = false;
break;
}
}
offset = iter.pos.offset;
bch2_trans_iter_exit(trans, &iter);
err:
if (bch2_err_matches(err, BCH_ERR_transaction_restart))
goto retry;
bch2_trans_put(trans);
return err ? false : ret;
}
static noinline bool bch2_dio_write_check_allocated(struct dio_write *dio)
{
struct bch_fs *c = dio->op.c;
struct bch_inode_info *inode = dio->inode;
struct bio *bio = &dio->op.wbio.bio;
return bch2_check_range_allocated(c, inode_inum(inode),
dio->op.pos.offset, bio_sectors(bio),
dio->op.opts.data_replicas,
dio->op.opts.compression != 0);
}
static void bch2_dio_write_loop_async(struct bch_write_op *);
static __always_inline long bch2_dio_write_done(struct dio_write *dio);
/*
* We're going to return -EIOCBQUEUED, but we haven't finished consuming the
* iov_iter yet, so we need to stash a copy of the iovec: it might be on the
* caller's stack, we're not guaranteed that it will live for the duration of
* the IO:
*/
static noinline int bch2_dio_write_copy_iov(struct dio_write *dio)
{
struct iovec *iov = dio->inline_vecs;
/*
* iov_iter has a single embedded iovec - nothing to do:
*/
if (iter_is_ubuf(&dio->iter))
return 0;
/*
* We don't currently handle non-iovec iov_iters here - return an error,
* and we'll fall back to doing the IO synchronously:
*/
if (!iter_is_iovec(&dio->iter))
return -1;
if (dio->iter.nr_segs > ARRAY_SIZE(dio->inline_vecs)) {
dio->iov = iov = kmalloc_array(dio->iter.nr_segs, sizeof(*iov),
GFP_KERNEL);
if (unlikely(!iov))
return -ENOMEM;
}
memcpy(iov, dio->iter.__iov, dio->iter.nr_segs * sizeof(*iov));
dio->iter.__iov = iov;
return 0;
}
static CLOSURE_CALLBACK(bch2_dio_write_flush_done)
{
closure_type(dio, struct dio_write, op.cl);
struct bch_fs *c = dio->op.c;
closure_debug_destroy(cl);
dio->op.error = bch2_journal_error(&c->journal);
bch2_dio_write_done(dio);
}
static noinline void bch2_dio_write_flush(struct dio_write *dio)
{
struct bch_fs *c = dio->op.c;
struct bch_inode_unpacked inode;
int ret;
dio->flush = 0;
closure_init(&dio->op.cl, NULL);
if (!dio->op.error) {
ret = bch2_inode_find_by_inum(c, inode_inum(dio->inode), &inode);
if (ret) {
dio->op.error = ret;
} else {
bch2_journal_flush_seq_async(&c->journal, inode.bi_journal_seq,
&dio->op.cl);
bch2_inode_flush_nocow_writes_async(c, dio->inode, &dio->op.cl);
}
}
if (dio->sync) {
closure_sync(&dio->op.cl);
closure_debug_destroy(&dio->op.cl);
} else {
continue_at(&dio->op.cl, bch2_dio_write_flush_done, NULL);
}
}
static __always_inline long bch2_dio_write_done(struct dio_write *dio)
{
struct kiocb *req = dio->req;
struct bch_inode_info *inode = dio->inode;
bool sync = dio->sync;
long ret;
if (unlikely(dio->flush)) {
bch2_dio_write_flush(dio);
if (!sync)
return -EIOCBQUEUED;
}
bch2_pagecache_block_put(inode);
kfree(dio->iov);
ret = dio->op.error ?: ((long) dio->written << 9);
bio_put(&dio->op.wbio.bio);
bch2_write_ref_put(dio->op.c, BCH_WRITE_REF_dio_write);
/* inode->i_dio_count is our ref on inode and thus bch_fs */
inode_dio_end(&inode->v);
if (ret < 0)
ret = bch2_err_class(ret);
if (!sync) {
req->ki_complete(req, ret);
ret = -EIOCBQUEUED;
}
return ret;
}
static __always_inline void bch2_dio_write_end(struct dio_write *dio)
{
struct bch_fs *c = dio->op.c;
struct kiocb *req = dio->req;
struct bch_inode_info *inode = dio->inode;
struct bio *bio = &dio->op.wbio.bio;
req->ki_pos += (u64) dio->op.written << 9;
dio->written += dio->op.written;
if (dio->extending) {
spin_lock(&inode->v.i_lock);
if (req->ki_pos > inode->v.i_size)
i_size_write(&inode->v, req->ki_pos);
spin_unlock(&inode->v.i_lock);
}
if (dio->op.i_sectors_delta || dio->quota_res.sectors) {
mutex_lock(&inode->ei_quota_lock);
__bch2_i_sectors_acct(c, inode, &dio->quota_res, dio->op.i_sectors_delta);
__bch2_quota_reservation_put(c, inode, &dio->quota_res);
mutex_unlock(&inode->ei_quota_lock);
}
bio_release_pages(bio, false);
if (unlikely(dio->op.error))
set_bit(EI_INODE_ERROR, &inode->ei_flags);
}
static __always_inline long bch2_dio_write_loop(struct dio_write *dio)
{
struct bch_fs *c = dio->op.c;
struct kiocb *req = dio->req;
struct address_space *mapping = dio->mapping;
struct bch_inode_info *inode = dio->inode;
struct bch_io_opts opts;
struct bio *bio = &dio->op.wbio.bio;
unsigned unaligned, iter_count;
bool sync = dio->sync, dropped_locks;
long ret;
bch2_inode_opts_get(&opts, c, &inode->ei_inode);
while (1) {
iter_count = dio->iter.count;
EBUG_ON(current->faults_disabled_mapping);
current->faults_disabled_mapping = mapping;
ret = bio_iov_iter_get_pages(bio, &dio->iter);
dropped_locks = fdm_dropped_locks();
current->faults_disabled_mapping = NULL;
/*
* If the fault handler returned an error but also signalled
* that it dropped & retook ei_pagecache_lock, we just need to
* re-shoot down the page cache and retry:
*/
if (dropped_locks && ret)
ret = 0;
if (unlikely(ret < 0))
goto err;
if (unlikely(dropped_locks)) {
ret = bch2_write_invalidate_inode_pages_range(mapping,
req->ki_pos,
req->ki_pos + iter_count - 1);
if (unlikely(ret))
goto err;
if (!bio->bi_iter.bi_size)
continue;
}
unaligned = bio->bi_iter.bi_size & (block_bytes(c) - 1);
bio->bi_iter.bi_size -= unaligned;
iov_iter_revert(&dio->iter, unaligned);
if (!bio->bi_iter.bi_size) {
/*
* bio_iov_iter_get_pages was only able to get <
* blocksize worth of pages:
*/
ret = -EFAULT;
goto err;
}
bch2_write_op_init(&dio->op, c, opts);
dio->op.end_io = sync
? NULL
: bch2_dio_write_loop_async;
dio->op.target = dio->op.opts.foreground_target;
dio->op.write_point = writepoint_hashed((unsigned long) current);
dio->op.nr_replicas = dio->op.opts.data_replicas;
dio->op.subvol = inode->ei_inum.subvol;
dio->op.pos = POS(inode->v.i_ino, (u64) req->ki_pos >> 9);
dio->op.devs_need_flush = &inode->ei_devs_need_flush;
if (sync)
dio->op.flags |= BCH_WRITE_SYNC;
dio->op.flags |= BCH_WRITE_CHECK_ENOSPC;
ret = bch2_quota_reservation_add(c, inode, &dio->quota_res,
bio_sectors(bio), true);
if (unlikely(ret))
goto err;
ret = bch2_disk_reservation_get(c, &dio->op.res, bio_sectors(bio),
dio->op.opts.data_replicas, 0);
if (unlikely(ret) &&
!bch2_dio_write_check_allocated(dio))
goto err;
task_io_account_write(bio->bi_iter.bi_size);
if (unlikely(dio->iter.count) &&
!dio->sync &&
!dio->loop &&
bch2_dio_write_copy_iov(dio))
dio->sync = sync = true;
dio->loop = true;
closure_call(&dio->op.cl, bch2_write, NULL, NULL);
if (!sync)
return -EIOCBQUEUED;
bch2_dio_write_end(dio);
if (likely(!dio->iter.count) || dio->op.error)
break;
bio_reset(bio, NULL, REQ_OP_WRITE | REQ_SYNC | REQ_IDLE);
}
out:
return bch2_dio_write_done(dio);
err:
dio->op.error = ret;
bio_release_pages(bio, false);
bch2_quota_reservation_put(c, inode, &dio->quota_res);
goto out;
}
static noinline __cold void bch2_dio_write_continue(struct dio_write *dio)
{
struct mm_struct *mm = dio->mm;
bio_reset(&dio->op.wbio.bio, NULL, REQ_OP_WRITE);
if (mm)
kthread_use_mm(mm);
bch2_dio_write_loop(dio);
if (mm)
kthread_unuse_mm(mm);
}
static void bch2_dio_write_loop_async(struct bch_write_op *op)
{
struct dio_write *dio = container_of(op, struct dio_write, op);
bch2_dio_write_end(dio);
if (likely(!dio->iter.count) || dio->op.error)
bch2_dio_write_done(dio);
else
bch2_dio_write_continue(dio);
}
ssize_t bch2_direct_write(struct kiocb *req, struct iov_iter *iter)
{
struct file *file = req->ki_filp;
struct address_space *mapping = file->f_mapping;
struct bch_inode_info *inode = file_bch_inode(file);
struct bch_fs *c = inode->v.i_sb->s_fs_info;
struct dio_write *dio;
struct bio *bio;
bool locked = true, extending;
ssize_t ret;
prefetch(&c->opts);
prefetch((void *) &c->opts + 64);
prefetch(&inode->ei_inode);
prefetch((void *) &inode->ei_inode + 64);
if (!bch2_write_ref_tryget(c, BCH_WRITE_REF_dio_write))
return -EROFS;
inode_lock(&inode->v);
ret = generic_write_checks(req, iter);
if (unlikely(ret <= 0))
goto err_put_write_ref;
ret = file_remove_privs(file);
if (unlikely(ret))
goto err_put_write_ref;
ret = file_update_time(file);
if (unlikely(ret))
goto err_put_write_ref;
if (unlikely((req->ki_pos|iter->count) & (block_bytes(c) - 1))) {
ret = -EINVAL;
goto err_put_write_ref;
}
inode_dio_begin(&inode->v);
bch2_pagecache_block_get(inode);
extending = req->ki_pos + iter->count > inode->v.i_size;
if (!extending) {
inode_unlock(&inode->v);
locked = false;
}
bio = bio_alloc_bioset(NULL,
bio_iov_vecs_to_alloc(iter, BIO_MAX_VECS),
REQ_OP_WRITE | REQ_SYNC | REQ_IDLE,
GFP_KERNEL,
&c->dio_write_bioset);
dio = container_of(bio, struct dio_write, op.wbio.bio);
dio->req = req;
dio->mapping = mapping;
dio->inode = inode;
dio->mm = current->mm;
dio->iov = NULL;
dio->loop = false;
dio->extending = extending;
dio->sync = is_sync_kiocb(req) || extending;
dio->flush = iocb_is_dsync(req) && !c->opts.journal_flush_disabled;
dio->quota_res.sectors = 0;
dio->written = 0;
dio->iter = *iter;
dio->op.c = c;
if (unlikely(mapping->nrpages)) {
ret = bch2_write_invalidate_inode_pages_range(mapping,
req->ki_pos,
req->ki_pos + iter->count - 1);
if (unlikely(ret))
goto err_put_bio;
}
ret = bch2_dio_write_loop(dio);
out:
if (locked)
inode_unlock(&inode->v);
return ret;
err_put_bio:
bch2_pagecache_block_put(inode);
bio_put(bio);
inode_dio_end(&inode->v);
err_put_write_ref:
bch2_write_ref_put(c, BCH_WRITE_REF_dio_write);
goto out;
}
void bch2_fs_fs_io_direct_exit(struct bch_fs *c)
{
bioset_exit(&c->dio_write_bioset);
bioset_exit(&c->dio_read_bioset);
}
int bch2_fs_fs_io_direct_init(struct bch_fs *c)
{
if (bioset_init(&c->dio_read_bioset,
4, offsetof(struct dio_read, rbio.bio),
BIOSET_NEED_BVECS))
return -BCH_ERR_ENOMEM_dio_read_bioset_init;
if (bioset_init(&c->dio_write_bioset,
4, offsetof(struct dio_write, op.wbio.bio),
BIOSET_NEED_BVECS))
return -BCH_ERR_ENOMEM_dio_write_bioset_init;
return 0;
}
#endif /* NO_BCACHEFS_FS */
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