--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+#ifndef NO_BCACHEFS_FS
+
+#include "bcachefs.h"
+#include "alloc_foreground.h"
+#include "bkey_buf.h"
+#include "fs-io.h"
+#include "fs-io-buffered.h"
+#include "fs-io-direct.h"
+#include "fs-io-pagecache.h"
+#include "io_read.h"
+#include "io_write.h"
+
+#include <linux/backing-dev.h>
+#include <linux/pagemap.h>
+#include <linux/writeback.h>
+
+static inline bool bio_full(struct bio *bio, unsigned len)
+{
+ if (bio->bi_vcnt >= bio->bi_max_vecs)
+ return true;
+ if (bio->bi_iter.bi_size > UINT_MAX - len)
+ return true;
+ return false;
+}
+
+/* readpage(s): */
+
+static void bch2_readpages_end_io(struct bio *bio)
+{
+ struct folio_iter fi;
+
+ bio_for_each_folio_all(fi, bio) {
+ if (!bio->bi_status) {
+ folio_mark_uptodate(fi.folio);
+ } else {
+ folio_clear_uptodate(fi.folio);
+ folio_set_error(fi.folio);
+ }
+ folio_unlock(fi.folio);
+ }
+
+ bio_put(bio);
+}
+
+struct readpages_iter {
+ struct address_space *mapping;
+ unsigned idx;
+ folios folios;
+};
+
+static int readpages_iter_init(struct readpages_iter *iter,
+ struct readahead_control *ractl)
+{
+ struct folio *folio;
+
+ *iter = (struct readpages_iter) { ractl->mapping };
+
+ while ((folio = __readahead_folio(ractl))) {
+ if (!bch2_folio_create(folio, GFP_KERNEL) ||
+ darray_push(&iter->folios, folio)) {
+ bch2_folio_release(folio);
+ ractl->_nr_pages += folio_nr_pages(folio);
+ ractl->_index -= folio_nr_pages(folio);
+ return iter->folios.nr ? 0 : -ENOMEM;
+ }
+
+ folio_put(folio);
+ }
+
+ return 0;
+}
+
+static inline struct folio *readpage_iter_peek(struct readpages_iter *iter)
+{
+ if (iter->idx >= iter->folios.nr)
+ return NULL;
+ return iter->folios.data[iter->idx];
+}
+
+static inline void readpage_iter_advance(struct readpages_iter *iter)
+{
+ iter->idx++;
+}
+
+static bool extent_partial_reads_expensive(struct bkey_s_c k)
+{
+ struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(k);
+ struct bch_extent_crc_unpacked crc;
+ const union bch_extent_entry *i;
+
+ bkey_for_each_crc(k.k, ptrs, crc, i)
+ if (crc.csum_type || crc.compression_type)
+ return true;
+ return false;
+}
+
+static int readpage_bio_extend(struct btree_trans *trans,
+ struct readpages_iter *iter,
+ struct bio *bio,
+ unsigned sectors_this_extent,
+ bool get_more)
+{
+ /* Don't hold btree locks while allocating memory: */
+ bch2_trans_unlock(trans);
+
+ while (bio_sectors(bio) < sectors_this_extent &&
+ bio->bi_vcnt < bio->bi_max_vecs) {
+ struct folio *folio = readpage_iter_peek(iter);
+ int ret;
+
+ if (folio) {
+ readpage_iter_advance(iter);
+ } else {
+ pgoff_t folio_offset = bio_end_sector(bio) >> PAGE_SECTORS_SHIFT;
+
+ if (!get_more)
+ break;
+
+ folio = xa_load(&iter->mapping->i_pages, folio_offset);
+ if (folio && !xa_is_value(folio))
+ break;
+
+ folio = filemap_alloc_folio(readahead_gfp_mask(iter->mapping), 0);
+ if (!folio)
+ break;
+
+ if (!__bch2_folio_create(folio, GFP_KERNEL)) {
+ folio_put(folio);
+ break;
+ }
+
+ ret = filemap_add_folio(iter->mapping, folio, folio_offset, GFP_KERNEL);
+ if (ret) {
+ __bch2_folio_release(folio);
+ folio_put(folio);
+ break;
+ }
+
+ folio_put(folio);
+ }
+
+ BUG_ON(folio_sector(folio) != bio_end_sector(bio));
+
+ BUG_ON(!bio_add_folio(bio, folio, folio_size(folio), 0));
+ }
+
+ return bch2_trans_relock(trans);
+}
+
+static void bchfs_read(struct btree_trans *trans,
+ struct bch_read_bio *rbio,
+ subvol_inum inum,
+ struct readpages_iter *readpages_iter)
+{
+ struct bch_fs *c = trans->c;
+ struct btree_iter iter;
+ struct bkey_buf sk;
+ int flags = BCH_READ_RETRY_IF_STALE|
+ BCH_READ_MAY_PROMOTE;
+ u32 snapshot;
+ int ret = 0;
+
+ rbio->c = c;
+ rbio->start_time = local_clock();
+ rbio->subvol = inum.subvol;
+
+ bch2_bkey_buf_init(&sk);
+retry:
+ bch2_trans_begin(trans);
+ iter = (struct btree_iter) { NULL };
+
+ ret = bch2_subvolume_get_snapshot(trans, inum.subvol, &snapshot);
+ if (ret)
+ goto err;
+
+ bch2_trans_iter_init(trans, &iter, BTREE_ID_extents,
+ SPOS(inum.inum, rbio->bio.bi_iter.bi_sector, snapshot),
+ BTREE_ITER_SLOTS);
+ while (1) {
+ struct bkey_s_c k;
+ unsigned bytes, sectors, offset_into_extent;
+ enum btree_id data_btree = BTREE_ID_extents;
+
+ /*
+ * read_extent -> io_time_reset may cause a transaction restart
+ * without returning an error, we need to check for that here:
+ */
+ ret = bch2_trans_relock(trans);
+ if (ret)
+ break;
+
+ bch2_btree_iter_set_pos(&iter,
+ POS(inum.inum, rbio->bio.bi_iter.bi_sector));
+
+ k = bch2_btree_iter_peek_slot(&iter);
+ ret = bkey_err(k);
+ if (ret)
+ break;
+
+ offset_into_extent = iter.pos.offset -
+ bkey_start_offset(k.k);
+ sectors = k.k->size - offset_into_extent;
+
+ bch2_bkey_buf_reassemble(&sk, c, k);
+
+ ret = bch2_read_indirect_extent(trans, &data_btree,
+ &offset_into_extent, &sk);
+ if (ret)
+ break;
+
+ k = bkey_i_to_s_c(sk.k);
+
+ sectors = min(sectors, k.k->size - offset_into_extent);
+
+ if (readpages_iter) {
+ ret = readpage_bio_extend(trans, readpages_iter, &rbio->bio, sectors,
+ extent_partial_reads_expensive(k));
+ if (ret)
+ break;
+ }
+
+ bytes = min(sectors, bio_sectors(&rbio->bio)) << 9;
+ swap(rbio->bio.bi_iter.bi_size, bytes);
+
+ if (rbio->bio.bi_iter.bi_size == bytes)
+ flags |= BCH_READ_LAST_FRAGMENT;
+
+ bch2_bio_page_state_set(&rbio->bio, k);
+
+ bch2_read_extent(trans, rbio, iter.pos,
+ data_btree, k, offset_into_extent, flags);
+
+ if (flags & BCH_READ_LAST_FRAGMENT)
+ break;
+
+ swap(rbio->bio.bi_iter.bi_size, bytes);
+ bio_advance(&rbio->bio, bytes);
+
+ ret = btree_trans_too_many_iters(trans);
+ if (ret)
+ break;
+ }
+err:
+ bch2_trans_iter_exit(trans, &iter);
+
+ if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
+ goto retry;
+
+ if (ret) {
+ bch_err_inum_offset_ratelimited(c,
+ iter.pos.inode,
+ iter.pos.offset << 9,
+ "read error %i from btree lookup", ret);
+ rbio->bio.bi_status = BLK_STS_IOERR;
+ bio_endio(&rbio->bio);
+ }
+
+ bch2_bkey_buf_exit(&sk, c);
+}
+
+void bch2_readahead(struct readahead_control *ractl)
+{
+ struct bch_inode_info *inode = to_bch_ei(ractl->mapping->host);
+ struct bch_fs *c = inode->v.i_sb->s_fs_info;
+ struct bch_io_opts opts;
+ struct btree_trans *trans = bch2_trans_get(c);
+ struct folio *folio;
+ struct readpages_iter readpages_iter;
+
+ bch2_inode_opts_get(&opts, c, &inode->ei_inode);
+
+ int ret = readpages_iter_init(&readpages_iter, ractl);
+ if (ret)
+ return;
+
+ bch2_pagecache_add_get(inode);
+
+ while ((folio = readpage_iter_peek(&readpages_iter))) {
+ unsigned n = min_t(unsigned,
+ readpages_iter.folios.nr -
+ readpages_iter.idx,
+ BIO_MAX_VECS);
+ struct bch_read_bio *rbio =
+ rbio_init(bio_alloc_bioset(NULL, n, REQ_OP_READ,
+ GFP_KERNEL, &c->bio_read),
+ opts);
+
+ readpage_iter_advance(&readpages_iter);
+
+ rbio->bio.bi_iter.bi_sector = folio_sector(folio);
+ rbio->bio.bi_end_io = bch2_readpages_end_io;
+ BUG_ON(!bio_add_folio(&rbio->bio, folio, folio_size(folio), 0));
+
+ bchfs_read(trans, rbio, inode_inum(inode),
+ &readpages_iter);
+ bch2_trans_unlock(trans);
+ }
+
+ bch2_pagecache_add_put(inode);
+
+ bch2_trans_put(trans);
+ darray_exit(&readpages_iter.folios);
+}
+
+static void __bchfs_readfolio(struct bch_fs *c, struct bch_read_bio *rbio,
+ subvol_inum inum, struct folio *folio)
+{
+ bch2_folio_create(folio, __GFP_NOFAIL);
+
+ rbio->bio.bi_opf = REQ_OP_READ|REQ_SYNC;
+ rbio->bio.bi_iter.bi_sector = folio_sector(folio);
+ BUG_ON(!bio_add_folio(&rbio->bio, folio, folio_size(folio), 0));
+
+ bch2_trans_run(c, (bchfs_read(trans, rbio, inum, NULL), 0));
+}
+
+static void bch2_read_single_folio_end_io(struct bio *bio)
+{
+ complete(bio->bi_private);
+}
+
+int bch2_read_single_folio(struct folio *folio, struct address_space *mapping)
+{
+ struct bch_inode_info *inode = to_bch_ei(mapping->host);
+ struct bch_fs *c = inode->v.i_sb->s_fs_info;
+ struct bch_read_bio *rbio;
+ struct bch_io_opts opts;
+ int ret;
+ DECLARE_COMPLETION_ONSTACK(done);
+
+ bch2_inode_opts_get(&opts, c, &inode->ei_inode);
+
+ rbio = rbio_init(bio_alloc_bioset(NULL, 1, REQ_OP_READ, GFP_KERNEL, &c->bio_read),
+ opts);
+ rbio->bio.bi_private = &done;
+ rbio->bio.bi_end_io = bch2_read_single_folio_end_io;
+
+ __bchfs_readfolio(c, rbio, inode_inum(inode), folio);
+ wait_for_completion(&done);
+
+ ret = blk_status_to_errno(rbio->bio.bi_status);
+ bio_put(&rbio->bio);
+
+ if (ret < 0)
+ return ret;
+
+ folio_mark_uptodate(folio);
+ return 0;
+}
+
+int bch2_read_folio(struct file *file, struct folio *folio)
+{
+ int ret;
+
+ ret = bch2_read_single_folio(folio, folio->mapping);
+ folio_unlock(folio);
+ return bch2_err_class(ret);
+}
+
+/* writepages: */
+
+struct bch_writepage_io {
+ struct bch_inode_info *inode;
+
+ /* must be last: */
+ struct bch_write_op op;
+};
+
+struct bch_writepage_state {
+ struct bch_writepage_io *io;
+ struct bch_io_opts opts;
+ struct bch_folio_sector *tmp;
+ unsigned tmp_sectors;
+};
+
+static inline struct bch_writepage_state bch_writepage_state_init(struct bch_fs *c,
+ struct bch_inode_info *inode)
+{
+ struct bch_writepage_state ret = { 0 };
+
+ bch2_inode_opts_get(&ret.opts, c, &inode->ei_inode);
+ return ret;
+}
+
+/*
+ * Determine when a writepage io is full. We have to limit writepage bios to a
+ * single page per bvec (i.e. 1MB with 4k pages) because that is the limit to
+ * what the bounce path in bch2_write_extent() can handle. In theory we could
+ * loosen this restriction for non-bounce I/O, but we don't have that context
+ * here. Ideally, we can up this limit and make it configurable in the future
+ * when the bounce path can be enhanced to accommodate larger source bios.
+ */
+static inline bool bch_io_full(struct bch_writepage_io *io, unsigned len)
+{
+ struct bio *bio = &io->op.wbio.bio;
+ return bio_full(bio, len) ||
+ (bio->bi_iter.bi_size + len > BIO_MAX_VECS * PAGE_SIZE);
+}
+
+static void bch2_writepage_io_done(struct bch_write_op *op)
+{
+ struct bch_writepage_io *io =
+ container_of(op, struct bch_writepage_io, op);
+ struct bch_fs *c = io->op.c;
+ struct bio *bio = &io->op.wbio.bio;
+ struct folio_iter fi;
+ unsigned i;
+
+ if (io->op.error) {
+ set_bit(EI_INODE_ERROR, &io->inode->ei_flags);
+
+ bio_for_each_folio_all(fi, bio) {
+ struct bch_folio *s;
+
+ folio_set_error(fi.folio);
+ mapping_set_error(fi.folio->mapping, -EIO);
+
+ s = __bch2_folio(fi.folio);
+ spin_lock(&s->lock);
+ for (i = 0; i < folio_sectors(fi.folio); i++)
+ s->s[i].nr_replicas = 0;
+ spin_unlock(&s->lock);
+ }
+ }
+
+ if (io->op.flags & BCH_WRITE_WROTE_DATA_INLINE) {
+ bio_for_each_folio_all(fi, bio) {
+ struct bch_folio *s;
+
+ s = __bch2_folio(fi.folio);
+ spin_lock(&s->lock);
+ for (i = 0; i < folio_sectors(fi.folio); i++)
+ s->s[i].nr_replicas = 0;
+ spin_unlock(&s->lock);
+ }
+ }
+
+ /*
+ * racing with fallocate can cause us to add fewer sectors than
+ * expected - but we shouldn't add more sectors than expected:
+ */
+ WARN_ON_ONCE(io->op.i_sectors_delta > 0);
+
+ /*
+ * (error (due to going RO) halfway through a page can screw that up
+ * slightly)
+ * XXX wtf?
+ BUG_ON(io->op.op.i_sectors_delta >= PAGE_SECTORS);
+ */
+
+ /*
+ * PageWriteback is effectively our ref on the inode - fixup i_blocks
+ * before calling end_page_writeback:
+ */
+ bch2_i_sectors_acct(c, io->inode, NULL, io->op.i_sectors_delta);
+
+ bio_for_each_folio_all(fi, bio) {
+ struct bch_folio *s = __bch2_folio(fi.folio);
+
+ if (atomic_dec_and_test(&s->write_count))
+ folio_end_writeback(fi.folio);
+ }
+
+ bio_put(&io->op.wbio.bio);
+}
+
+static void bch2_writepage_do_io(struct bch_writepage_state *w)
+{
+ struct bch_writepage_io *io = w->io;
+
+ w->io = NULL;
+ closure_call(&io->op.cl, bch2_write, NULL, NULL);
+}
+
+/*
+ * Get a bch_writepage_io and add @page to it - appending to an existing one if
+ * possible, else allocating a new one:
+ */
+static void bch2_writepage_io_alloc(struct bch_fs *c,
+ struct writeback_control *wbc,
+ struct bch_writepage_state *w,
+ struct bch_inode_info *inode,
+ u64 sector,
+ unsigned nr_replicas)
+{
+ struct bch_write_op *op;
+
+ w->io = container_of(bio_alloc_bioset(NULL, BIO_MAX_VECS,
+ REQ_OP_WRITE,
+ GFP_KERNEL,
+ &c->writepage_bioset),
+ struct bch_writepage_io, op.wbio.bio);
+
+ w->io->inode = inode;
+ op = &w->io->op;
+ bch2_write_op_init(op, c, w->opts);
+ op->target = w->opts.foreground_target;
+ op->nr_replicas = nr_replicas;
+ op->res.nr_replicas = nr_replicas;
+ op->write_point = writepoint_hashed(inode->ei_last_dirtied);
+ op->subvol = inode->ei_subvol;
+ op->pos = POS(inode->v.i_ino, sector);
+ op->end_io = bch2_writepage_io_done;
+ op->devs_need_flush = &inode->ei_devs_need_flush;
+ op->wbio.bio.bi_iter.bi_sector = sector;
+ op->wbio.bio.bi_opf = wbc_to_write_flags(wbc);
+}
+
+static int __bch2_writepage(struct folio *folio,
+ struct writeback_control *wbc,
+ void *data)
+{
+ struct bch_inode_info *inode = to_bch_ei(folio->mapping->host);
+ struct bch_fs *c = inode->v.i_sb->s_fs_info;
+ struct bch_writepage_state *w = data;
+ struct bch_folio *s;
+ unsigned i, offset, f_sectors, nr_replicas_this_write = U32_MAX;
+ loff_t i_size = i_size_read(&inode->v);
+ int ret;
+
+ EBUG_ON(!folio_test_uptodate(folio));
+
+ /* Is the folio fully inside i_size? */
+ if (folio_end_pos(folio) <= i_size)
+ goto do_io;
+
+ /* Is the folio fully outside i_size? (truncate in progress) */
+ if (folio_pos(folio) >= i_size) {
+ folio_unlock(folio);
+ return 0;
+ }
+
+ /*
+ * The folio straddles i_size. It must be zeroed out on each and every
+ * writepage invocation because it may be mmapped. "A file is mapped
+ * in multiples of the folio size. For a file that is not a multiple of
+ * the folio size, the remaining memory is zeroed when mapped, and
+ * writes to that region are not written out to the file."
+ */
+ folio_zero_segment(folio,
+ i_size - folio_pos(folio),
+ folio_size(folio));
+do_io:
+ f_sectors = folio_sectors(folio);
+ s = bch2_folio(folio);
+
+ if (f_sectors > w->tmp_sectors) {
+ kfree(w->tmp);
+ w->tmp = kcalloc(f_sectors, sizeof(struct bch_folio_sector), __GFP_NOFAIL);
+ w->tmp_sectors = f_sectors;
+ }
+
+ /*
+ * Things get really hairy with errors during writeback:
+ */
+ ret = bch2_get_folio_disk_reservation(c, inode, folio, false);
+ BUG_ON(ret);
+
+ /* Before unlocking the page, get copy of reservations: */
+ spin_lock(&s->lock);
+ memcpy(w->tmp, s->s, sizeof(struct bch_folio_sector) * f_sectors);
+
+ for (i = 0; i < f_sectors; i++) {
+ if (s->s[i].state < SECTOR_dirty)
+ continue;
+
+ nr_replicas_this_write =
+ min_t(unsigned, nr_replicas_this_write,
+ s->s[i].nr_replicas +
+ s->s[i].replicas_reserved);
+ }
+
+ for (i = 0; i < f_sectors; i++) {
+ if (s->s[i].state < SECTOR_dirty)
+ continue;
+
+ s->s[i].nr_replicas = w->opts.compression
+ ? 0 : nr_replicas_this_write;
+
+ s->s[i].replicas_reserved = 0;
+ bch2_folio_sector_set(folio, s, i, SECTOR_allocated);
+ }
+ spin_unlock(&s->lock);
+
+ BUG_ON(atomic_read(&s->write_count));
+ atomic_set(&s->write_count, 1);
+
+ BUG_ON(folio_test_writeback(folio));
+ folio_start_writeback(folio);
+
+ folio_unlock(folio);
+
+ offset = 0;
+ while (1) {
+ unsigned sectors = 0, dirty_sectors = 0, reserved_sectors = 0;
+ u64 sector;
+
+ while (offset < f_sectors &&
+ w->tmp[offset].state < SECTOR_dirty)
+ offset++;
+
+ if (offset == f_sectors)
+ break;
+
+ while (offset + sectors < f_sectors &&
+ w->tmp[offset + sectors].state >= SECTOR_dirty) {
+ reserved_sectors += w->tmp[offset + sectors].replicas_reserved;
+ dirty_sectors += w->tmp[offset + sectors].state == SECTOR_dirty;
+ sectors++;
+ }
+ BUG_ON(!sectors);
+
+ sector = folio_sector(folio) + offset;
+
+ if (w->io &&
+ (w->io->op.res.nr_replicas != nr_replicas_this_write ||
+ bch_io_full(w->io, sectors << 9) ||
+ bio_end_sector(&w->io->op.wbio.bio) != sector))
+ bch2_writepage_do_io(w);
+
+ if (!w->io)
+ bch2_writepage_io_alloc(c, wbc, w, inode, sector,
+ nr_replicas_this_write);
+
+ atomic_inc(&s->write_count);
+
+ BUG_ON(inode != w->io->inode);
+ BUG_ON(!bio_add_folio(&w->io->op.wbio.bio, folio,
+ sectors << 9, offset << 9));
+
+ /* Check for writing past i_size: */
+ WARN_ONCE((bio_end_sector(&w->io->op.wbio.bio) << 9) >
+ round_up(i_size, block_bytes(c)) &&
+ !test_bit(BCH_FS_emergency_ro, &c->flags),
+ "writing past i_size: %llu > %llu (unrounded %llu)\n",
+ bio_end_sector(&w->io->op.wbio.bio) << 9,
+ round_up(i_size, block_bytes(c)),
+ i_size);
+
+ w->io->op.res.sectors += reserved_sectors;
+ w->io->op.i_sectors_delta -= dirty_sectors;
+ w->io->op.new_i_size = i_size;
+
+ offset += sectors;
+ }
+
+ if (atomic_dec_and_test(&s->write_count))
+ folio_end_writeback(folio);
+
+ return 0;
+}
+
+int bch2_writepages(struct address_space *mapping, struct writeback_control *wbc)
+{
+ struct bch_fs *c = mapping->host->i_sb->s_fs_info;
+ struct bch_writepage_state w =
+ bch_writepage_state_init(c, to_bch_ei(mapping->host));
+ struct blk_plug plug;
+ int ret;
+
+ blk_start_plug(&plug);
+ ret = write_cache_pages(mapping, wbc, __bch2_writepage, &w);
+ if (w.io)
+ bch2_writepage_do_io(&w);
+ blk_finish_plug(&plug);
+ kfree(w.tmp);
+ return bch2_err_class(ret);
+}
+
+/* buffered writes: */
+
+int bch2_write_begin(struct file *file, struct address_space *mapping,
+ loff_t pos, unsigned len,
+ struct page **pagep, void **fsdata)
+{
+ struct bch_inode_info *inode = to_bch_ei(mapping->host);
+ struct bch_fs *c = inode->v.i_sb->s_fs_info;
+ struct bch2_folio_reservation *res;
+ struct folio *folio;
+ unsigned offset;
+ int ret = -ENOMEM;
+
+ res = kmalloc(sizeof(*res), GFP_KERNEL);
+ if (!res)
+ return -ENOMEM;
+
+ bch2_folio_reservation_init(c, inode, res);
+ *fsdata = res;
+
+ bch2_pagecache_add_get(inode);
+
+ folio = __filemap_get_folio(mapping, pos >> PAGE_SHIFT,
+ FGP_LOCK|FGP_WRITE|FGP_CREAT|FGP_STABLE,
+ mapping_gfp_mask(mapping));
+ if (IS_ERR_OR_NULL(folio))
+ goto err_unlock;
+
+ offset = pos - folio_pos(folio);
+ len = min_t(size_t, len, folio_end_pos(folio) - pos);
+
+ if (folio_test_uptodate(folio))
+ goto out;
+
+ /* If we're writing entire folio, don't need to read it in first: */
+ if (!offset && len == folio_size(folio))
+ goto out;
+
+ if (!offset && pos + len >= inode->v.i_size) {
+ folio_zero_segment(folio, len, folio_size(folio));
+ flush_dcache_folio(folio);
+ goto out;
+ }
+
+ if (folio_pos(folio) >= inode->v.i_size) {
+ folio_zero_segments(folio, 0, offset, offset + len, folio_size(folio));
+ flush_dcache_folio(folio);
+ goto out;
+ }
+readpage:
+ ret = bch2_read_single_folio(folio, mapping);
+ if (ret)
+ goto err;
+out:
+ ret = bch2_folio_set(c, inode_inum(inode), &folio, 1);
+ if (ret)
+ goto err;
+
+ ret = bch2_folio_reservation_get(c, inode, folio, res, offset, len);
+ if (ret) {
+ if (!folio_test_uptodate(folio)) {
+ /*
+ * If the folio hasn't been read in, we won't know if we
+ * actually need a reservation - we don't actually need
+ * to read here, we just need to check if the folio is
+ * fully backed by uncompressed data:
+ */
+ goto readpage;
+ }
+
+ goto err;
+ }
+
+ *pagep = &folio->page;
+ return 0;
+err:
+ folio_unlock(folio);
+ folio_put(folio);
+ *pagep = NULL;
+err_unlock:
+ bch2_pagecache_add_put(inode);
+ kfree(res);
+ *fsdata = NULL;
+ return bch2_err_class(ret);
+}
+
+int bch2_write_end(struct file *file, struct address_space *mapping,
+ loff_t pos, unsigned len, unsigned copied,
+ struct page *page, void *fsdata)
+{
+ struct bch_inode_info *inode = to_bch_ei(mapping->host);
+ struct bch_fs *c = inode->v.i_sb->s_fs_info;
+ struct bch2_folio_reservation *res = fsdata;
+ struct folio *folio = page_folio(page);
+ unsigned offset = pos - folio_pos(folio);
+
+ lockdep_assert_held(&inode->v.i_rwsem);
+ BUG_ON(offset + copied > folio_size(folio));
+
+ if (unlikely(copied < len && !folio_test_uptodate(folio))) {
+ /*
+ * The folio needs to be read in, but that would destroy
+ * our partial write - simplest thing is to just force
+ * userspace to redo the write:
+ */
+ folio_zero_range(folio, 0, folio_size(folio));
+ flush_dcache_folio(folio);
+ copied = 0;
+ }
+
+ spin_lock(&inode->v.i_lock);
+ if (pos + copied > inode->v.i_size)
+ i_size_write(&inode->v, pos + copied);
+ spin_unlock(&inode->v.i_lock);
+
+ if (copied) {
+ if (!folio_test_uptodate(folio))
+ folio_mark_uptodate(folio);
+
+ bch2_set_folio_dirty(c, inode, folio, res, offset, copied);
+
+ inode->ei_last_dirtied = (unsigned long) current;
+ }
+
+ folio_unlock(folio);
+ folio_put(folio);
+ bch2_pagecache_add_put(inode);
+
+ bch2_folio_reservation_put(c, inode, res);
+ kfree(res);
+
+ return copied;
+}
+
+static noinline void folios_trunc(folios *fs, struct folio **fi)
+{
+ while (fs->data + fs->nr > fi) {
+ struct folio *f = darray_pop(fs);
+
+ folio_unlock(f);
+ folio_put(f);
+ }
+}
+
+static int __bch2_buffered_write(struct bch_inode_info *inode,
+ struct address_space *mapping,
+ struct iov_iter *iter,
+ loff_t pos, unsigned len)
+{
+ struct bch_fs *c = inode->v.i_sb->s_fs_info;
+ struct bch2_folio_reservation res;
+ folios fs;
+ struct folio *f;
+ unsigned copied = 0, f_offset, f_copied;
+ u64 end = pos + len, f_pos, f_len;
+ loff_t last_folio_pos = inode->v.i_size;
+ int ret = 0;
+
+ BUG_ON(!len);
+
+ bch2_folio_reservation_init(c, inode, &res);
+ darray_init(&fs);
+
+ ret = bch2_filemap_get_contig_folios_d(mapping, pos, end,
+ FGP_LOCK|FGP_WRITE|FGP_STABLE|FGP_CREAT,
+ mapping_gfp_mask(mapping),
+ &fs);
+ if (ret)
+ goto out;
+
+ BUG_ON(!fs.nr);
+
+ f = darray_first(fs);
+ if (pos != folio_pos(f) && !folio_test_uptodate(f)) {
+ ret = bch2_read_single_folio(f, mapping);
+ if (ret)
+ goto out;
+ }
+
+ f = darray_last(fs);
+ end = min(end, folio_end_pos(f));
+ last_folio_pos = folio_pos(f);
+ if (end != folio_end_pos(f) && !folio_test_uptodate(f)) {
+ if (end >= inode->v.i_size) {
+ folio_zero_range(f, 0, folio_size(f));
+ } else {
+ ret = bch2_read_single_folio(f, mapping);
+ if (ret)
+ goto out;
+ }
+ }
+
+ ret = bch2_folio_set(c, inode_inum(inode), fs.data, fs.nr);
+ if (ret)
+ goto out;
+
+ f_pos = pos;
+ f_offset = pos - folio_pos(darray_first(fs));
+ darray_for_each(fs, fi) {
+ f = *fi;
+ f_len = min(end, folio_end_pos(f)) - f_pos;
+
+ /*
+ * XXX: per POSIX and fstests generic/275, on -ENOSPC we're
+ * supposed to write as much as we have disk space for.
+ *
+ * On failure here we should still write out a partial page if
+ * we aren't completely out of disk space - we don't do that
+ * yet:
+ */
+ ret = bch2_folio_reservation_get(c, inode, f, &res, f_offset, f_len);
+ if (unlikely(ret)) {
+ folios_trunc(&fs, fi);
+ if (!fs.nr)
+ goto out;
+
+ end = min(end, folio_end_pos(darray_last(fs)));
+ break;
+ }
+
+ f_pos = folio_end_pos(f);
+ f_offset = 0;
+ }
+
+ if (mapping_writably_mapped(mapping))
+ darray_for_each(fs, fi)
+ flush_dcache_folio(*fi);
+
+ f_pos = pos;
+ f_offset = pos - folio_pos(darray_first(fs));
+ darray_for_each(fs, fi) {
+ f = *fi;
+ f_len = min(end, folio_end_pos(f)) - f_pos;
+ f_copied = copy_page_from_iter_atomic(&f->page, f_offset, f_len, iter);
+ if (!f_copied) {
+ folios_trunc(&fs, fi);
+ break;
+ }
+
+ if (!folio_test_uptodate(f) &&
+ f_copied != folio_size(f) &&
+ pos + copied + f_copied < inode->v.i_size) {
+ iov_iter_revert(iter, f_copied);
+ folio_zero_range(f, 0, folio_size(f));
+ folios_trunc(&fs, fi);
+ break;
+ }
+
+ flush_dcache_folio(f);
+ copied += f_copied;
+
+ if (f_copied != f_len) {
+ folios_trunc(&fs, fi + 1);
+ break;
+ }
+
+ f_pos = folio_end_pos(f);
+ f_offset = 0;
+ }
+
+ if (!copied)
+ goto out;
+
+ end = pos + copied;
+
+ spin_lock(&inode->v.i_lock);
+ if (end > inode->v.i_size)
+ i_size_write(&inode->v, end);
+ spin_unlock(&inode->v.i_lock);
+
+ f_pos = pos;
+ f_offset = pos - folio_pos(darray_first(fs));
+ darray_for_each(fs, fi) {
+ f = *fi;
+ f_len = min(end, folio_end_pos(f)) - f_pos;
+
+ if (!folio_test_uptodate(f))
+ folio_mark_uptodate(f);
+
+ bch2_set_folio_dirty(c, inode, f, &res, f_offset, f_len);
+
+ f_pos = folio_end_pos(f);
+ f_offset = 0;
+ }
+
+ inode->ei_last_dirtied = (unsigned long) current;
+out:
+ darray_for_each(fs, fi) {
+ folio_unlock(*fi);
+ folio_put(*fi);
+ }
+
+ /*
+ * If the last folio added to the mapping starts beyond current EOF, we
+ * performed a short write but left around at least one post-EOF folio.
+ * Clean up the mapping before we return.
+ */
+ if (last_folio_pos >= inode->v.i_size)
+ truncate_pagecache(&inode->v, inode->v.i_size);
+
+ darray_exit(&fs);
+ bch2_folio_reservation_put(c, inode, &res);
+
+ return copied ?: ret;
+}
+
+static ssize_t bch2_buffered_write(struct kiocb *iocb, struct iov_iter *iter)
+{
+ struct file *file = iocb->ki_filp;
+ struct address_space *mapping = file->f_mapping;
+ struct bch_inode_info *inode = file_bch_inode(file);
+ loff_t pos = iocb->ki_pos;
+ ssize_t written = 0;
+ int ret = 0;
+
+ bch2_pagecache_add_get(inode);
+
+ do {
+ unsigned offset = pos & (PAGE_SIZE - 1);
+ unsigned bytes = iov_iter_count(iter);
+again:
+ /*
+ * Bring in the user page that we will copy from _first_.
+ * Otherwise there's a nasty deadlock on copying from the
+ * same page as we're writing to, without it being marked
+ * up-to-date.
+ *
+ * Not only is this an optimisation, but it is also required
+ * to check that the address is actually valid, when atomic
+ * usercopies are used, below.
+ */
+ if (unlikely(fault_in_iov_iter_readable(iter, bytes))) {
+ bytes = min_t(unsigned long, iov_iter_count(iter),
+ PAGE_SIZE - offset);
+
+ if (unlikely(fault_in_iov_iter_readable(iter, bytes))) {
+ ret = -EFAULT;
+ break;
+ }
+ }
+
+ if (unlikely(fatal_signal_pending(current))) {
+ ret = -EINTR;
+ break;
+ }
+
+ ret = __bch2_buffered_write(inode, mapping, iter, pos, bytes);
+ if (unlikely(ret < 0))
+ break;
+
+ cond_resched();
+
+ if (unlikely(ret == 0)) {
+ /*
+ * If we were unable to copy any data at all, we must
+ * fall back to a single segment length write.
+ *
+ * If we didn't fallback here, we could livelock
+ * because not all segments in the iov can be copied at
+ * once without a pagefault.
+ */
+ bytes = min_t(unsigned long, PAGE_SIZE - offset,
+ iov_iter_single_seg_count(iter));
+ goto again;
+ }
+ pos += ret;
+ written += ret;
+ ret = 0;
+
+ balance_dirty_pages_ratelimited(mapping);
+ } while (iov_iter_count(iter));
+
+ bch2_pagecache_add_put(inode);
+
+ return written ? written : ret;
+}
+
+ssize_t bch2_write_iter(struct kiocb *iocb, struct iov_iter *from)
+{
+ struct file *file = iocb->ki_filp;
+ struct bch_inode_info *inode = file_bch_inode(file);
+ ssize_t ret;
+
+ if (iocb->ki_flags & IOCB_DIRECT) {
+ ret = bch2_direct_write(iocb, from);
+ goto out;
+ }
+
+ inode_lock(&inode->v);
+
+ ret = generic_write_checks(iocb, from);
+ if (ret <= 0)
+ goto unlock;
+
+ ret = file_remove_privs(file);
+ if (ret)
+ goto unlock;
+
+ ret = file_update_time(file);
+ if (ret)
+ goto unlock;
+
+ ret = bch2_buffered_write(iocb, from);
+ if (likely(ret > 0))
+ iocb->ki_pos += ret;
+unlock:
+ inode_unlock(&inode->v);
+
+ if (ret > 0)
+ ret = generic_write_sync(iocb, ret);
+out:
+ return bch2_err_class(ret);
+}
+
+void bch2_fs_fs_io_buffered_exit(struct bch_fs *c)
+{
+ bioset_exit(&c->writepage_bioset);
+}
+
+int bch2_fs_fs_io_buffered_init(struct bch_fs *c)
+{
+ if (bioset_init(&c->writepage_bioset,
+ 4, offsetof(struct bch_writepage_io, op.wbio.bio),
+ BIOSET_NEED_BVECS))
+ return -BCH_ERR_ENOMEM_writepage_bioset_init;
+
+ return 0;
+}
+
+#endif /* NO_BCACHEFS_FS */
projects / bcachefs-tools-debian / blobdiff