Commit 7554a8bb authored by Kent Overstreet's avatar Kent Overstreet
Browse files

bcachefs: Ensure buffered writes write as much as they can 



This adds a new helper, bch2_folio_reservation_get_partial(), which
reserves as many blocks as possible and may return partial success.

__bch2_buffered_write() is switched to the new helper - this fixes
fstests generic/275, the write until -ENOSPC test.

generic/230 now fails: this appears to be a test bug, where xfs_io isn't
looping after a partial write to get the error code.

Signed-off-by: default avatarKent Overstreet <kent.overstreet@linux.dev>
parent 95924420

fs/bcachefs/fs-io-buffered.c

+17 −15
Original line number Diff line number Diff line
@@ -863,24 +863,26 @@ static int __bch2_buffered_write(struct bch_inode_info *inode, 
	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);



		/*

		 * 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)

		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;

		}

fs/bcachefs/fs-io-pagecache.c

+29 −8
Original line number Diff line number Diff line
@@ -423,7 +423,7 @@ int bch2_folio_reservation_get(struct bch_fs *c, 
			struct bch_inode_info *inode,

			struct folio *folio,

			struct bch2_folio_reservation *res,

			unsigned offset, unsigned len)

			size_t offset, size_t len)

{

	struct bch_folio *s = bch2_folio_create(folio, 0);

	unsigned i, disk_sectors = 0, quota_sectors = 0;
@@ -437,8 +437,7 @@ int bch2_folio_reservation_get(struct bch_fs *c, 
	for (i = round_down(offset, block_bytes(c)) >> 9;

	     i < round_up(offset + len, block_bytes(c)) >> 9;

	     i++) {

		disk_sectors += sectors_to_reserve(&s->s[i],

						res->disk.nr_replicas);

		disk_sectors += sectors_to_reserve(&s->s[i], res->disk.nr_replicas);

		quota_sectors += s->s[i].state == SECTOR_unallocated;

	}
@@ -449,12 +448,9 @@ int bch2_folio_reservation_get(struct bch_fs *c, 
	}



	if (quota_sectors) {

		ret = bch2_quota_reservation_add(c, inode, &res->quota,

						 quota_sectors, true);

		ret = bch2_quota_reservation_add(c, inode, &res->quota, quota_sectors, true);

		if (unlikely(ret)) {

			struct disk_reservation tmp = {

				.sectors = disk_sectors

			};

			struct disk_reservation tmp = { .sectors = disk_sectors };



			bch2_disk_reservation_put(c, &tmp);

			res->disk.sectors -= disk_sectors;
@@ -465,6 +461,31 @@ int bch2_folio_reservation_get(struct bch_fs *c, 
	return 0;

}



ssize_t bch2_folio_reservation_get_partial(struct bch_fs *c,

			struct bch_inode_info *inode,

			struct folio *folio,

			struct bch2_folio_reservation *res,

			size_t offset, size_t len)

{

	size_t l, reserved = 0;

	int ret;



	while ((l = len - reserved)) {

		while ((ret = bch2_folio_reservation_get(c, inode, folio, res, offset, l))) {

			if ((offset & (block_bytes(c) - 1)) + l <= block_bytes(c))

				return reserved ?: ret;



			len = reserved + l;

			l /= 2;

		}



		offset += l;

		reserved += l;

	}



	return reserved;

}



static void bch2_clear_folio_bits(struct folio *folio)

{

	struct bch_inode_info *inode = to_bch_ei(folio->mapping->host);

fs/bcachefs/fs-io-pagecache.h

+6 −1
Original line number Diff line number Diff line
@@ -153,7 +153,12 @@ int bch2_folio_reservation_get(struct bch_fs *, 
			struct bch_inode_info *,

			struct folio *,

			struct bch2_folio_reservation *,

			unsigned, unsigned);

			size_t, size_t);

ssize_t bch2_folio_reservation_get_partial(struct bch_fs *,

			struct bch_inode_info *,

			struct folio *,

			struct bch2_folio_reservation *,

			size_t, size_t);



void bch2_set_folio_dirty(struct bch_fs *,

			  struct bch_inode_info *,