// 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)
folio_end_read(fi.folio, bio->bi_status == BLK_STS_OK);
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;
int ret = 0;
rbio->c = c;
rbio->start_time = local_clock();
rbio->subvol = inum.subvol;
bch2_bkey_buf_init(&sk);
bch2_trans_begin(trans);
bch2_trans_iter_init(trans, &iter, BTREE_ID_extents,
POS(inum.inum, rbio->bio.bi_iter.bi_sector),
BTREE_ITER_slots);
while (1) {
struct bkey_s_c k;
unsigned bytes, sectors, offset_into_extent;
enum btree_id data_btree = BTREE_ID_extents;
bch2_trans_begin(trans);
u32 snapshot;
ret = bch2_subvolume_get_snapshot(trans, inum.subvol, &snapshot);
if (ret)
goto err;
bch2_btree_iter_set_snapshot(&iter, snapshot);
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)
goto err;
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)
goto err;
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)
goto err;
}
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);
err:
if (ret &&
!bch2_err_matches(ret, BCH_ERR_transaction_restart))
break;
}
bch2_trans_iter_exit(trans, &iter);
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 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);
struct btree_trans *trans = bch2_trans_get(c);
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_trans_put(trans);
bch2_pagecache_add_put(inode);
darray_exit(&readpages_iter.folios);
}
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);
if (!bch2_folio_create(folio, GFP_KERNEL))
return -ENOMEM;
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;
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, inode_inum(inode), NULL), 0));
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;
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);
*/
/*
* The writeback flag is effectively our ref on the inode -
* fixup i_blocks before calling folio_end_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_inum.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_NOFS|__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 folio **foliop, 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_WRITEBEGIN | fgf_set_order(len),
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;
}
*foliop = folio;
return 0;
err:
folio_unlock(folio);
folio_put(folio);
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 folio *folio, 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;
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_WRITEBEGIN | fgf_set_order(len),
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) {
ssize_t f_reserved;
f = *fi;
f_len = min(end, folio_end_pos(f)) - f_pos;
f_reserved = bch2_folio_reservation_get_partial(c, inode, f, &res, f_offset, f_len);
if (unlikely(f_reserved != f_len)) {
if (f_reserved < 0) {
if (f == darray_first(fs)) {
ret = f_reserved;
goto out;
}
folios_trunc(&fs, fi);
end = min(end, folio_end_pos(darray_last(fs)));
} else {
folios_trunc(&fs, fi + 1);
end = f_pos + f_reserved;
}
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_folio_from_iter_atomic(f, 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 */
Codebase Browser
linux