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bcachefs: Change __bch2_writepage() to not write to holes

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Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This commit is contained in:
Kent Overstreet 2019-07-29 12:24:36 -04:00 committed by Kent Overstreet
parent e10d309471
commit 7f5e31e1a4
1 changed files with 86 additions and 56 deletions
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142
fs/bcachefs/fs-io.c
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@ -31,6 +31,15 @@
#include <trace/events/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;
}
struct quota_res {
u64 sectors;
};
@ -517,6 +526,7 @@ struct bch_page_sector {
};
struct bch_page_state {
atomic_t write_count;
struct bch_page_sector s[PAGE_SECTORS];
};
@ -835,31 +845,6 @@ bool bch2_release_folio(struct folio *folio, gfp_t gfp_mask)
return true;
}
/* readpages/writepages: */
static bool bio_can_add_page_contig(struct bio *bio, struct page *page)
{
sector_t offset = (sector_t) page->index << PAGE_SECTOR_SHIFT;
return bio->bi_vcnt < bio->bi_max_vecs &&
bio_end_sector(bio) == offset;
}
static int bio_add_page_contig(struct bio *bio, struct page *page)
{
sector_t offset = (sector_t) page->index << PAGE_SECTOR_SHIFT;
EBUG_ON(!bio->bi_max_vecs);
if (!bio->bi_vcnt)
bio->bi_iter.bi_sector = offset;
else if (!bio_can_add_page_contig(bio, page))
return -1;
BUG_ON(!bio_add_page(bio, page, PAGE_SIZE, 0));
return 0;
}
/* readpage(s): */
static void bch2_readpages_end_io(struct bio *bio)
@ -1132,7 +1117,9 @@ static void __bchfs_readpage(struct bch_fs *c, struct bch_read_bio *rbio,
bch2_page_state_create(page, __GFP_NOFAIL);
rbio->bio.bi_opf = REQ_OP_READ|REQ_SYNC;
bio_add_page_contig(&rbio->bio, page);
rbio->bio.bi_iter.bi_sector =
(sector_t) page->index << PAGE_SECTOR_SHIFT;
BUG_ON(!bio_add_page(&rbio->bio, page, PAGE_SIZE, 0));
bch2_trans_init(&trans, c, 0, 0);
iter = bch2_trans_get_iter(&trans, BTREE_ID_EXTENTS, POS_MIN,
@ -1243,8 +1230,12 @@ static void bch2_writepage_io_done(struct closure *cl)
i_sectors_acct(c, io->op.inode, NULL,
io->op.sectors_added - (s64) io->new_sectors);
bio_for_each_segment_all(bvec, bio, iter)
end_page_writeback(bvec->bv_page);
bio_for_each_segment_all(bvec, bio, iter) {
struct bch_page_state *s = __bch2_page_state(bvec->bv_page);
if (atomic_dec_and_test(&s->write_count))
end_page_writeback(bvec->bv_page);
}
closure_return_with_destructor(&io->cl, bch2_writepage_io_free);
}
@ -1265,11 +1256,10 @@ static void bch2_writepage_do_io(struct bch_writepage_state *w)
static void bch2_writepage_io_alloc(struct bch_fs *c,
struct bch_writepage_state *w,
struct bch_inode_info *inode,
struct page *page,
u64 sector,
unsigned nr_replicas)
{
struct bch_write_op *op;
u64 offset = (u64) page->index << PAGE_SECTOR_SHIFT;
w->io = container_of(bio_alloc_bioset(NULL, BIO_MAX_VECS,
REQ_OP_WRITE,
@ -1284,8 +1274,8 @@ static void bch2_writepage_io_alloc(struct bch_fs *c,
op->nr_replicas = nr_replicas;
op->res.nr_replicas = nr_replicas;
op->write_point = writepoint_hashed(inode->ei_last_dirtied);
op->pos = POS(inode->v.i_ino, offset);
op->wbio.bio.bi_iter.bi_sector = offset;
op->pos = POS(inode->v.i_ino, sector);
op->wbio.bio.bi_iter.bi_sector = sector;
}
static int __bch2_writepage(struct folio *folio,
@ -1296,12 +1286,10 @@ static int __bch2_writepage(struct folio *folio,
struct bch_inode_info *inode = to_bch_ei(page->mapping->host);
struct bch_fs *c = inode->v.i_sb->s_fs_info;
struct bch_writepage_state *w = data;
struct bch_page_state *s;
unsigned offset, nr_replicas_this_write = U32_MAX;
unsigned dirty_sectors = 0, reserved_sectors = 0;
struct bch_page_state *s, orig;
unsigned i, offset, nr_replicas_this_write = U32_MAX;
loff_t i_size = i_size_read(&inode->v);
pgoff_t end_index = i_size >> PAGE_SHIFT;
unsigned i;
int ret;
EBUG_ON(!PageUptodate(page));
@ -1336,48 +1324,90 @@ do_io:
return 0;
}
for (i = 0; i < PAGE_SECTORS; i++)
/* Before unlocking the page, get copy of reservations: */
orig = *s;
for (i = 0; i < PAGE_SECTORS; i++) {
if (s->s[i].state == SECTOR_UNALLOCATED)
continue;
nr_replicas_this_write =
min_t(unsigned, nr_replicas_this_write,
s->s[i].nr_replicas +
s->s[i].replicas_reserved);
/* Before unlocking the page, transfer reservation to w->io: */
}
for (i = 0; i < PAGE_SECTORS; i++) {
if (s->s[i].state == SECTOR_UNALLOCATED)
continue;
s->s[i].nr_replicas = w->opts.compression
? 0 : nr_replicas_this_write;
reserved_sectors += s->s[i].replicas_reserved;
s->s[i].replicas_reserved = 0;
dirty_sectors += s->s[i].state == SECTOR_DIRTY;
s->s[i].state = SECTOR_ALLOCATED;
}
BUG_ON(atomic_read(&s->write_count));
atomic_set(&s->write_count, 1);
BUG_ON(PageWriteback(page));
set_page_writeback(page);
unlock_page(page);
if (w->io &&
(w->io->op.op.res.nr_replicas != nr_replicas_this_write ||
!bio_can_add_page_contig(&w->io->op.op.wbio.bio, page)))
bch2_writepage_do_io(w);
offset = 0;
while (1) {
unsigned sectors = 1, dirty_sectors = 0, reserved_sectors = 0;
u64 sector;
if (!w->io)
bch2_writepage_io_alloc(c, w, inode, page,
nr_replicas_this_write);
while (offset < PAGE_SECTORS &&
orig.s[offset].state == SECTOR_UNALLOCATED)
offset++;
w->io->new_sectors += dirty_sectors;
if (offset == PAGE_SECTORS)
break;
BUG_ON(inode != w->io->op.inode);
BUG_ON(bio_add_page_contig(&w->io->op.op.wbio.bio, page));
sector = ((u64) page->index << PAGE_SECTOR_SHIFT) + offset;
w->io->op.op.res.sectors += reserved_sectors;
w->io->op.new_i_size = i_size;
while (offset + sectors < PAGE_SECTORS &&
orig.s[offset + sectors].state != SECTOR_UNALLOCATED)
sectors++;
if (wbc->sync_mode == WB_SYNC_ALL)
w->io->op.op.wbio.bio.bi_opf |= REQ_SYNC;
for (i = offset; i < offset + sectors; i++) {
reserved_sectors += orig.s[i].replicas_reserved;
dirty_sectors += orig.s[i].state == SECTOR_DIRTY;
}
if (w->io &&
(w->io->op.op.res.nr_replicas != nr_replicas_this_write ||
bio_full(&w->io->op.op.wbio.bio, PAGE_SIZE) ||
bio_end_sector(&w->io->op.op.wbio.bio) != sector))
bch2_writepage_do_io(w);
if (!w->io)
bch2_writepage_io_alloc(c, w, inode, sector,
nr_replicas_this_write);
w->io->new_sectors += dirty_sectors;
atomic_inc(&s->write_count);
BUG_ON(inode != w->io->op.inode);
BUG_ON(!bio_add_page(&w->io->op.op.wbio.bio, page,
sectors << 9, offset << 9));
w->io->op.op.res.sectors += reserved_sectors;
w->io->op.new_i_size = i_size;
if (wbc->sync_mode == WB_SYNC_ALL)
w->io->op.op.wbio.bio.bi_opf |= REQ_SYNC;
offset += sectors;
}
if (atomic_dec_and_test(&s->write_count))
end_page_writeback(page);
return 0;
}