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linux/fs/bcachefs/io.h
Kent Overstreet a8b3a677e7 bcachefs: Nocow support 
This adds support for nocow mode, where we do writes in-place when
possible. Patch components:

 - New boolean filesystem and inode option, nocow: note that when nocow
   is enabled, data checksumming and compression are implicitly disabled

 - To prevent in-place writes from racing with data moves
   (data_update.c) or bucket reuse (i.e. a bucket being reused and
   re-allocated while a nocow write is in flight, we have a new locking
   mechanism.

   Buckets can be locked for either data update or data move, using a
   fixed size hash table of two_state_shared locks. We don't have any
   chaining, meaning updates and moves to different buckets that hash to
   the same lock will wait unnecessarily - we'll want to watch for this
   becoming an issue.

 - The allocator path also needs to check for in-place writes in flight
   to a given bucket before giving it out: thus we add another counter
   to bucket_alloc_state so we can track this.

 - Fsync now may need to issue cache flushes to block devices instead of
   flushing the journal. We add a device bitmask to bch_inode_info,
   ei_devs_need_flush, which tracks devices that need to have flushes
   issued - note that this will lead to unnecessary flushes when other
   codepaths have already issued flushes, we may want to replace this with
   a sequence number.

 - New nocow write path: look up extents, and if they're writable write
   to them - otherwise fall back to the normal COW write path.

XXX: switch to sequence numbers instead of bitmask for devs needing
journal flush

XXX: ei_quota_lock being a mutex means bch2_nocow_write_done() needs to
run in process context - see if we can improve this

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:09:51 -04:00

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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _BCACHEFS_IO_H
#define _BCACHEFS_IO_H
#include "checksum.h"
#include "bkey_buf.h"
#include "io_types.h"
#define to_wbio(_bio) \
container_of((_bio), struct bch_write_bio, bio)
#define to_rbio(_bio) \
container_of((_bio), struct bch_read_bio, bio)
void bch2_bio_free_pages_pool(struct bch_fs *, struct bio *);
void bch2_bio_alloc_pages_pool(struct bch_fs *, struct bio *, size_t);
#ifndef CONFIG_BCACHEFS_NO_LATENCY_ACCT
void bch2_latency_acct(struct bch_dev *, u64, int);
#else
static inline void bch2_latency_acct(struct bch_dev *ca, u64 submit_time, int rw) {}
#endif
void bch2_submit_wbio_replicas(struct bch_write_bio *, struct bch_fs *,
enum bch_data_type, const struct bkey_i *, bool);
#define BLK_STS_REMOVED ((__force blk_status_t)128)
const char *bch2_blk_status_to_str(blk_status_t);
enum bch_write_flags {
__BCH_WRITE_ALLOC_NOWAIT,
__BCH_WRITE_CACHED,
__BCH_WRITE_DATA_ENCODED,
__BCH_WRITE_PAGES_STABLE,
__BCH_WRITE_PAGES_OWNED,
__BCH_WRITE_ONLY_SPECIFIED_DEVS,
__BCH_WRITE_WROTE_DATA_INLINE,
__BCH_WRITE_FROM_INTERNAL,
__BCH_WRITE_CHECK_ENOSPC,
__BCH_WRITE_SYNC,
__BCH_WRITE_MOVE,
__BCH_WRITE_IN_WORKER,
__BCH_WRITE_DONE,
__BCH_WRITE_IO_ERROR,
__BCH_WRITE_CONVERT_UNWRITTEN,
};
#define BCH_WRITE_ALLOC_NOWAIT (1U << __BCH_WRITE_ALLOC_NOWAIT)
#define BCH_WRITE_CACHED (1U << __BCH_WRITE_CACHED)
#define BCH_WRITE_DATA_ENCODED (1U << __BCH_WRITE_DATA_ENCODED)
#define BCH_WRITE_PAGES_STABLE (1U << __BCH_WRITE_PAGES_STABLE)
#define BCH_WRITE_PAGES_OWNED (1U << __BCH_WRITE_PAGES_OWNED)
#define BCH_WRITE_ONLY_SPECIFIED_DEVS (1U << __BCH_WRITE_ONLY_SPECIFIED_DEVS)
#define BCH_WRITE_WROTE_DATA_INLINE (1U << __BCH_WRITE_WROTE_DATA_INLINE)
#define BCH_WRITE_FROM_INTERNAL (1U << __BCH_WRITE_FROM_INTERNAL)
#define BCH_WRITE_CHECK_ENOSPC (1U << __BCH_WRITE_CHECK_ENOSPC)
#define BCH_WRITE_SYNC (1U << __BCH_WRITE_SYNC)
#define BCH_WRITE_MOVE (1U << __BCH_WRITE_MOVE)
/* Internal: */
#define BCH_WRITE_IN_WORKER (1U << __BCH_WRITE_IN_WORKER)
#define BCH_WRITE_DONE (1U << __BCH_WRITE_DONE)
#define BCH_WRITE_IO_ERROR (1U << __BCH_WRITE_IO_ERROR)
#define BCH_WRITE_CONVERT_UNWRITTEN (1U << __BCH_WRITE_CONVERT_UNWRITTEN)
static inline struct workqueue_struct *index_update_wq(struct bch_write_op *op)
{
return op->alloc_reserve == RESERVE_movinggc
? op->c->copygc_wq
: op->c->btree_update_wq;
}
int bch2_sum_sector_overwrites(struct btree_trans *, struct btree_iter *,
struct bkey_i *, bool *, s64 *, s64 *);
int bch2_extent_update(struct btree_trans *, subvol_inum,
struct btree_iter *, struct bkey_i *,
struct disk_reservation *, u64, s64 *, bool);
int bch2_extent_fallocate(struct btree_trans *, subvol_inum, struct btree_iter *,
unsigned, struct bch_io_opts, s64 *,
struct write_point_specifier);
int bch2_fpunch_at(struct btree_trans *, struct btree_iter *,
subvol_inum, u64, s64 *);
int bch2_fpunch(struct bch_fs *c, subvol_inum, u64, u64, s64 *);
static inline void bch2_write_op_init(struct bch_write_op *op, struct bch_fs *c,
struct bch_io_opts opts)
{
op->c = c;
op->end_io = NULL;
op->flags = 0;
op->written = 0;
op->error = 0;
op->csum_type = bch2_data_checksum_type(c, opts);
op->compression_type = bch2_compression_opt_to_type[opts.compression];
op->nr_replicas = 0;
op->nr_replicas_required = c->opts.data_replicas_required;
op->alloc_reserve = RESERVE_none;
op->incompressible = 0;
op->open_buckets.nr = 0;
op->devs_have.nr = 0;
op->target = 0;
op->opts = opts;
op->subvol = 0;
op->pos = POS_MAX;
op->version = ZERO_VERSION;
op->write_point = (struct write_point_specifier) { 0 };
op->res = (struct disk_reservation) { 0 };
op->new_i_size = U64_MAX;
op->i_sectors_delta = 0;
op->devs_need_flush = NULL;
}
void bch2_write(struct closure *);
void bch2_write_point_do_index_updates(struct work_struct *);
static inline struct bch_write_bio *wbio_init(struct bio *bio)
{
struct bch_write_bio *wbio = to_wbio(bio);
memset(&wbio->wbio, 0, sizeof(wbio->wbio));
return wbio;
}
struct bch_devs_mask;
struct cache_promote_op;
struct extent_ptr_decoded;
int __bch2_read_indirect_extent(struct btree_trans *, unsigned *,
struct bkey_buf *);
static inline int bch2_read_indirect_extent(struct btree_trans *trans,
enum btree_id *data_btree,
unsigned *offset_into_extent,
struct bkey_buf *k)
{
if (k->k->k.type != KEY_TYPE_reflink_p)
return 0;
*data_btree = BTREE_ID_reflink;
return __bch2_read_indirect_extent(trans, offset_into_extent, k);
}
enum bch_read_flags {
BCH_READ_RETRY_IF_STALE = 1 << 0,
BCH_READ_MAY_PROMOTE = 1 << 1,
BCH_READ_USER_MAPPED = 1 << 2,
BCH_READ_NODECODE = 1 << 3,
BCH_READ_LAST_FRAGMENT = 1 << 4,
/* internal: */
BCH_READ_MUST_BOUNCE = 1 << 5,
BCH_READ_MUST_CLONE = 1 << 6,
BCH_READ_IN_RETRY = 1 << 7,
};
int __bch2_read_extent(struct btree_trans *, struct bch_read_bio *,
struct bvec_iter, struct bpos, enum btree_id,
struct bkey_s_c, unsigned,
struct bch_io_failures *, unsigned);
static inline void bch2_read_extent(struct btree_trans *trans,
struct bch_read_bio *rbio, struct bpos read_pos,
enum btree_id data_btree, struct bkey_s_c k,
unsigned offset_into_extent, unsigned flags)
{
__bch2_read_extent(trans, rbio, rbio->bio.bi_iter, read_pos,
data_btree, k, offset_into_extent, NULL, flags);
}
void __bch2_read(struct bch_fs *, struct bch_read_bio *, struct bvec_iter,
subvol_inum, struct bch_io_failures *, unsigned flags);
static inline void bch2_read(struct bch_fs *c, struct bch_read_bio *rbio,
subvol_inum inum)
{
struct bch_io_failures failed = { .nr = 0 };
BUG_ON(rbio->_state);
rbio->c = c;
rbio->start_time = local_clock();
rbio->subvol = inum.subvol;
__bch2_read(c, rbio, rbio->bio.bi_iter, inum, &failed,
BCH_READ_RETRY_IF_STALE|
BCH_READ_MAY_PROMOTE|
BCH_READ_USER_MAPPED);
}
static inline struct bch_read_bio *rbio_init(struct bio *bio,
struct bch_io_opts opts)
{
struct bch_read_bio *rbio = to_rbio(bio);
rbio->_state = 0;
rbio->promote = NULL;
rbio->opts = opts;
return rbio;
}
void bch2_fs_io_exit(struct bch_fs *);
int bch2_fs_io_init(struct bch_fs *);
#endif /* _BCACHEFS_IO_H */
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