From 70d41c9e276c5e7b130d328a6ece92c9130a6572 Mon Sep 17 00:00:00 2001 From: Kent Overstreet Date: Sun, 28 May 2023 00:35:35 -0400 Subject: [PATCH] bcachefs: Avoid __GFP_NOFAIL We've been using __GFP_NOFAIL for allocating struct bch_folio, our private per-folio state. However, that struct is variable size - it holds state for each sector in the folio, and folios can be quite large now, which means it's possible for bch_folio to be larger than PAGE_SIZE now. __GFP_NOFAIL allocations are undesirable in normal circumstances, but particularly so at >= PAGE_SIZE, and warnings are emitted for that. So, this patch adds proper error paths and eliminates most uses of __GFP_NOFAIL. Also, do some more cleanup of gfp flags w.r.t. btree node locks: we can use GFP_KERNEL, but only if we're not holding btree locks, and if we are holding btree locks we should be using GFP_NOWAIT. Signed-off-by: Kent Overstreet --- fs/bcachefs/fs-io.c | 91 +++++++++++++++++++++++++-------------------- 1 file changed, 50 insertions(+), 41 deletions(-) diff --git a/fs/bcachefs/fs-io.c b/fs/bcachefs/fs-io.c index 64897cee84943..cf48f9a0d4e1f 100644 --- a/fs/bcachefs/fs-io.c +++ b/fs/bcachefs/fs-io.c @@ -574,7 +574,7 @@ static struct bch_folio *__bch2_folio_create(struct folio *folio, gfp_t gfp) s = kzalloc(sizeof(*s) + sizeof(struct bch_folio_sector) * - folio_sectors(folio), GFP_NOFS|gfp); + folio_sectors(folio), gfp); if (!s) return NULL; @@ -601,7 +601,7 @@ static void __bch2_folio_set(struct folio *folio, unsigned pg_offset, unsigned pg_len, unsigned nr_ptrs, unsigned state) { - struct bch_folio *s = bch2_folio_create(folio, __GFP_NOFAIL); + struct bch_folio *s = bch2_folio(folio); unsigned i, sectors = folio_sectors(folio); BUG_ON(pg_offset >= sectors); @@ -630,11 +630,25 @@ static int bch2_folio_set(struct bch_fs *c, subvol_inum inum, struct btree_trans trans; struct btree_iter iter; struct bkey_s_c k; + struct bch_folio *s; u64 offset = folio_sector(folios[0]); - unsigned folio_idx = 0; + unsigned folio_idx; u32 snapshot; + bool need_set = false; int ret; + for (folio_idx = 0; folio_idx < nr_folios; folio_idx++) { + s = bch2_folio_create(folios[folio_idx], GFP_KERNEL); + if (!s) + return -ENOMEM; + + need_set |= !s->uptodate; + } + + if (!need_set) + return 0; + + folio_idx = 0; bch2_trans_init(&trans, c, 0, 0); retry: bch2_trans_begin(&trans); @@ -659,7 +673,7 @@ retry: BUG_ON(k.k->p.offset < folio_start); BUG_ON(bkey_start_offset(k.k) > folio_end); - if (!bch2_folio_create(folio, __GFP_NOFAIL)->uptodate) + if (!bch2_folio(folio)->uptodate) __bch2_folio_set(folio, folio_offset, folio_len, nr_ptrs, state); if (k.k->p.offset < folio_end) @@ -1051,15 +1065,8 @@ vm_fault_t bch2_page_mkwrite(struct vm_fault *vmf) len = min_t(loff_t, folio_size(folio), isize - folio_pos(folio)); - if (!bch2_folio_create(folio, __GFP_NOFAIL)->uptodate) { - if (bch2_folio_set(c, inode_inum(inode), &folio, 1)) { - folio_unlock(folio); - ret = VM_FAULT_SIGBUS; - goto out; - } - } - - if (bch2_folio_reservation_get(c, inode, folio, &res, 0, len)) { + if (bch2_folio_set(c, inode_inum(inode), &folio, 1) ?: + bch2_folio_reservation_get(c, inode, folio, &res, 0, len)) { folio_unlock(folio); ret = VM_FAULT_SIGBUS; goto out; @@ -1139,7 +1146,7 @@ static int readpages_iter_init(struct readpages_iter *iter, darray_for_each(iter->folios, fi) { ractl->_nr_pages -= 1U << folio_order(*fi); - __bch2_folio_create(*fi, __GFP_NOFAIL); + __bch2_folio_create(*fi, __GFP_NOFAIL|GFP_KERNEL); folio_put(*fi); folio_put(*fi); } @@ -1171,11 +1178,15 @@ static bool extent_partial_reads_expensive(struct bkey_s_c k) return false; } -static void readpage_bio_extend(struct readpages_iter *iter, - struct bio *bio, - unsigned sectors_this_extent, - bool get_more) +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); @@ -1197,12 +1208,12 @@ static void readpage_bio_extend(struct readpages_iter *iter, if (!folio) break; - if (!__bch2_folio_create(folio, 0)) { + if (!__bch2_folio_create(folio, GFP_KERNEL)) { folio_put(folio); break; } - ret = filemap_add_folio(iter->mapping, folio, folio_offset, GFP_NOFS); + ret = filemap_add_folio(iter->mapping, folio, folio_offset, GFP_KERNEL); if (ret) { __bch2_folio_release(folio); folio_put(folio); @@ -1216,6 +1227,8 @@ static void readpage_bio_extend(struct readpages_iter *iter, BUG_ON(!bio_add_folio(bio, folio, folio_size(folio), 0)); } + + return bch2_trans_relock(trans); } static void bchfs_read(struct btree_trans *trans, @@ -1283,9 +1296,12 @@ retry: sectors = min(sectors, k.k->size - offset_into_extent); - if (readpages_iter) - readpage_bio_extend(readpages_iter, &rbio->bio, sectors, - extent_partial_reads_expensive(k)); + if (readpages_iter) { + ret = readpage_bio_extend(trans, readpages_iter, &rbio->bio, sectors, + extent_partial_reads_expensive(k)); + if (ret) + break; + } bytes = min(sectors, bio_sectors(&rbio->bio)) << 9; swap(rbio->bio.bi_iter.bi_size, bytes); @@ -1594,7 +1610,7 @@ static int __bch2_writepage(struct folio *folio, folio_size(folio)); do_io: f_sectors = folio_sectors(folio); - s = bch2_folio_create(folio, __GFP_NOFAIL); + s = bch2_folio(folio); if (f_sectors > w->tmp_sectors) { kfree(w->tmp); @@ -1776,11 +1792,9 @@ readpage: if (ret) goto err; out: - if (!bch2_folio_create(folio, __GFP_NOFAIL)->uptodate) { - ret = bch2_folio_set(c, inode_inum(inode), &folio, 1); - if (ret) - goto err; - } + 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) { @@ -1916,19 +1930,16 @@ static int __bch2_buffered_write(struct bch_inode_info *inode, } } + ret = bch2_folio_set(c, inode_inum(inode), folios.data, folios.nr); + if (ret) + goto out; + f_pos = pos; f_offset = pos - folio_pos(darray_first(folios)); darray_for_each(folios, fi) { struct folio *f = *fi; u64 f_len = min(end, folio_end_pos(f)) - f_pos; - if (!bch2_folio_create(f, __GFP_NOFAIL)->uptodate) { - ret = bch2_folio_set(c, inode_inum(inode), fi, - folios.data + folios.nr - fi); - if (ret) - goto out; - } - /* * XXX: per POSIX and fstests generic/275, on -ENOSPC we're * supposed to write as much as we have disk space for. @@ -2884,11 +2895,9 @@ static int __bch2_truncate_folio(struct bch_inode_info *inode, goto unlock; } - if (!s->uptodate) { - ret = bch2_folio_set(c, inode_inum(inode), &folio, 1); - if (ret) - goto unlock; - } + ret = bch2_folio_set(c, inode_inum(inode), &folio, 1); + if (ret) + goto unlock; for (i = round_up(start_offset, block_bytes(c)) >> 9; i < round_down(end_offset, block_bytes(c)) >> 9;