From 7554a8bb6ddeeca87fa8abd1d9766111477a6643 Mon Sep 17 00:00:00 2001
From: Kent Overstreet <kent.overstreet@linux.dev>
Date: Sun, 10 Sep 2023 17:29:39 -0400
Subject: [PATCH] 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: Kent Overstreet <kent.overstreet@linux.dev>
---
fs/bcachefs/fs-io-buffered.c | 32 ++++++++++++++++--------------
fs/bcachefs/fs-io-pagecache.c | 37 +++++++++++++++++++++++++++--------
fs/bcachefs/fs-io-pagecache.h | 7 ++++++-
3 files changed, 52 insertions(+), 24 deletions(-)
diff --git a/fs/bcachefs/fs-io-buffered.c b/fs/bcachefs/fs-io-buffered.c
index 1355d618f9883..cc33d763f7221 100644
--- a/fs/bcachefs/fs-io-buffered.c
+++ b/fs/bcachefs/fs-io-buffered.c
@@ -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);
+
+ 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;
+ }
- /*
- * 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;
}
diff --git a/fs/bcachefs/fs-io-pagecache.c b/fs/bcachefs/fs-io-pagecache.c
index 872283e5bd1e2..a9cc5cad9cc99 100644
--- a/fs/bcachefs/fs-io-pagecache.c
+++ b/fs/bcachefs/fs-io-pagecache.c
@@ -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);
diff --git a/fs/bcachefs/fs-io-pagecache.h b/fs/bcachefs/fs-io-pagecache.h
index 828c3d7c8f199..fd7d692c087e1 100644
--- a/fs/bcachefs/fs-io-pagecache.h
+++ b/fs/bcachefs/fs-io-pagecache.h
@@ -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 *,
--
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