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-rw-r--r--fs/bcachefs/fs-io-direct.c677
1 files changed, 677 insertions, 0 deletions
diff --git a/fs/bcachefs/fs-io-direct.c b/fs/bcachefs/fs-io-direct.c
new file mode 100644
index 0000000000..84e20c3ada
--- /dev/null
+++ b/fs/bcachefs/fs-io-direct.c
@@ -0,0 +1,677 @@
+// 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);
+
+ if ((offset|iter->count) & (block_bytes(c) - 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));
+ 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;
+
+ 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 = generic_file_read_iter(iocb, iter);
+ 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);
+
+ /* 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_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);
+ }
+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);
+
+ inode_lock(&inode->v);
+
+ ret = generic_write_checks(req, iter);
+ if (unlikely(ret <= 0))
+ goto err;
+
+ ret = file_remove_privs(file);
+ if (unlikely(ret))
+ goto err;
+
+ ret = file_update_time(file);
+ if (unlikely(ret))
+ goto err;
+
+ if (unlikely((req->ki_pos|iter->count) & (block_bytes(c) - 1)))
+ goto err;
+
+ 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,
+ 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);
+err:
+ if (locked)
+ inode_unlock(&inode->v);
+ return ret;
+err_put_bio:
+ bch2_pagecache_block_put(inode);
+ bio_put(bio);
+ inode_dio_end(&inode->v);
+ goto err;
+}
+
+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 */