bcachefs: New io_misc.c helpers

This pulls the non vfs specific parts of truncate and finsert/fcollapse
out of fs-io.c, and moves them to io_misc.c.

This is prep work for logging these operations, to make them atomic in
the event of a crash.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

5 files changed, 250 insertions, 192 deletions

diff --git a/fs/bcachefs/fs-io.c b/fs/bcachefs/fs-io.c
index 0b0b3b0d6c7d..b36513eb3d16 100644
--- a/fs/bcachefs/fs-io.c
+++ b/fs/bcachefs/fs-io.c
@@ -391,33 +391,12 @@ static int bch2_extend(struct mnt_idmap *idmap,
 	return bch2_setattr_nonsize(idmap, inode, iattr);
 }
 
-static int bch2_truncate_finish_fn(struct btree_trans *trans,
-				   struct bch_inode_info *inode,
-				   struct bch_inode_unpacked *bi,
-				   void *p)
-{
-	bi->bi_flags &= ~BCH_INODE_I_SIZE_DIRTY;
-	return 0;
-}
-
-static int bch2_truncate_start_fn(struct btree_trans *trans,
-				  struct bch_inode_info *inode,
-				  struct bch_inode_unpacked *bi, void *p)
-{
-	u64 *new_i_size = p;
-
-	bi->bi_flags |= BCH_INODE_I_SIZE_DIRTY;
-	bi->bi_size = *new_i_size;
-	return 0;
-}
-
-int bch2_truncate(struct mnt_idmap *idmap,
+int bchfs_truncate(struct mnt_idmap *idmap,
 		  struct bch_inode_info *inode, struct iattr *iattr)
 {
 	struct bch_fs *c = inode->v.i_sb->s_fs_info;
 	struct address_space *mapping = inode->v.i_mapping;
 	struct bch_inode_unpacked inode_u;
-	u64 new_i_size = iattr->ia_size;
 	s64 i_sectors_delta = 0;
 	int ret = 0;
 
@@ -466,6 +445,8 @@ int bch2_truncate(struct mnt_idmap *idmap,
 	if (unlikely(ret < 0))
 		goto err;
 
+	truncate_setsize(&inode->v, iattr->ia_size);
+
 	/*
 	 * When extending, we're going to write the new i_size to disk
 	 * immediately so we need to flush anything above the current on disk
@@ -487,32 +468,22 @@ int bch2_truncate(struct mnt_idmap *idmap,
 	if (ret)
 		goto err;
 
-	mutex_lock(&inode->ei_update_lock);
-	ret = bch2_write_inode(c, inode, bch2_truncate_start_fn,
-			       &new_i_size, 0);
-	mutex_unlock(&inode->ei_update_lock);
+	ret = bch2_truncate(c, inode_inum(inode), iattr->ia_size, &i_sectors_delta);
+	bch2_i_sectors_acct(c, inode, NULL, i_sectors_delta);
 
-	if (unlikely(ret))
+	if (unlikely(ret)) {
+		/*
+		 * If we error here, VFS caches are now inconsistent with btree
+		 */
+		set_bit(EI_INODE_ERROR, &inode->ei_flags);
 		goto err;
-
-	truncate_setsize(&inode->v, iattr->ia_size);
-
-	ret = bch2_fpunch(c, inode_inum(inode),
-			round_up(iattr->ia_size, block_bytes(c)) >> 9,
-			U64_MAX, &i_sectors_delta);
-	bch2_i_sectors_acct(c, inode, NULL, i_sectors_delta);
+	}
 
 	bch2_fs_inconsistent_on(!inode->v.i_size && inode->v.i_blocks &&
 				!bch2_journal_error(&c->journal), c,
 				"inode %lu truncated to 0 but i_blocks %llu (ondisk %lli)",
 				inode->v.i_ino, (u64) inode->v.i_blocks,
 				inode->ei_inode.bi_sectors);
-	if (unlikely(ret))
-		goto err;
-
-	mutex_lock(&inode->ei_update_lock);
-	ret = bch2_write_inode(c, inode, bch2_truncate_finish_fn, NULL, 0);
-	mutex_unlock(&inode->ei_update_lock);
 
 	ret = bch2_setattr_nonsize(idmap, inode, iattr);
 err:
@@ -577,175 +548,33 @@ static long bchfs_fcollapse_finsert(struct bch_inode_info *inode,
 {
 	struct bch_fs *c = inode->v.i_sb->s_fs_info;
 	struct address_space *mapping = inode->v.i_mapping;
-	struct bkey_buf copy;
-	struct btree_trans trans;
-	struct btree_iter src, dst, del;
-	loff_t shift, new_size;
-	u64 src_start;
+	s64 i_sectors_delta = 0;
 	int ret = 0;
 
 	if ((offset | len) & (block_bytes(c) - 1))
 		return -EINVAL;
 
 	if (insert) {
-		if (inode->v.i_sb->s_maxbytes - inode->v.i_size < len)
-			return -EFBIG;
-
 		if (offset >= inode->v.i_size)
 			return -EINVAL;
-
-		src_start	= U64_MAX;
-		shift		= len;
 	} else {
 		if (offset + len >= inode->v.i_size)
 			return -EINVAL;
-
-		src_start	= offset + len;
-		shift		= -len;
 	}
 
-	new_size = inode->v.i_size + shift;
-
 	ret = bch2_write_invalidate_inode_pages_range(mapping, offset, LLONG_MAX);
 	if (ret)
 		return ret;
 
-	if (insert) {
-		i_size_write(&inode->v, new_size);
-		mutex_lock(&inode->ei_update_lock);
-		ret = bch2_write_inode_size(c, inode, new_size,
-					    ATTR_MTIME|ATTR_CTIME);
-		mutex_unlock(&inode->ei_update_lock);
-	} else {
-		s64 i_sectors_delta = 0;
-
-		ret = bch2_fpunch(c, inode_inum(inode),
-				  offset >> 9, (offset + len) >> 9,
-				  &i_sectors_delta);
-		bch2_i_sectors_acct(c, inode, NULL, i_sectors_delta);
+	if (insert)
+		i_size_write(&inode->v, inode->v.i_size + len);
 
-		if (ret)
-			return ret;
-	}
-
-	bch2_bkey_buf_init(&copy);
-	bch2_trans_init(&trans, c, BTREE_ITER_MAX, 1024);
-	bch2_trans_iter_init(&trans, &src, BTREE_ID_extents,
-			POS(inode->v.i_ino, src_start >> 9),
-			BTREE_ITER_INTENT);
-	bch2_trans_copy_iter(&dst, &src);
-	bch2_trans_copy_iter(&del, &src);
-
-	while (ret == 0 ||
-	       bch2_err_matches(ret, BCH_ERR_transaction_restart)) {
-		struct disk_reservation disk_res =
-			bch2_disk_reservation_init(c, 0);
-		struct bkey_i delete;
-		struct bkey_s_c k;
-		struct bpos next_pos;
-		struct bpos move_pos = POS(inode->v.i_ino, offset >> 9);
-		struct bpos atomic_end;
-		unsigned trigger_flags = 0;
-		u32 snapshot;
-
-		bch2_trans_begin(&trans);
-
-		ret = bch2_subvolume_get_snapshot(&trans,
-					inode->ei_subvol, &snapshot);
-		if (ret)
-			continue;
-
-		bch2_btree_iter_set_snapshot(&src, snapshot);
-		bch2_btree_iter_set_snapshot(&dst, snapshot);
-		bch2_btree_iter_set_snapshot(&del, snapshot);
-
-		bch2_trans_begin(&trans);
-
-		k = insert
-			? bch2_btree_iter_peek_prev(&src)
-			: bch2_btree_iter_peek_upto(&src, POS(inode->v.i_ino, U64_MAX));
-		if ((ret = bkey_err(k)))
-			continue;
-
-		if (!k.k || k.k->p.inode != inode->v.i_ino)
-			break;
-
-		if (insert &&
-		    bkey_le(k.k->p, POS(inode->v.i_ino, offset >> 9)))
-			break;
-reassemble:
-		bch2_bkey_buf_reassemble(&copy, c, k);
-
-		if (insert &&
-		    bkey_lt(bkey_start_pos(k.k), move_pos))
-			bch2_cut_front(move_pos, copy.k);
-
-		copy.k->k.p.offset += shift >> 9;
-		bch2_btree_iter_set_pos(&dst, bkey_start_pos(&copy.k->k));
-
-		ret = bch2_extent_atomic_end(&trans, &dst, copy.k, &atomic_end);
-		if (ret)
-			continue;
-
-		if (!bkey_eq(atomic_end, copy.k->k.p)) {
-			if (insert) {
-				move_pos = atomic_end;
-				move_pos.offset -= shift >> 9;
-				goto reassemble;
-			} else {
-				bch2_cut_back(atomic_end, copy.k);
-			}
-		}
-
-		bkey_init(&delete.k);
-		delete.k.p = copy.k->k.p;
-		delete.k.size = copy.k->k.size;
-		delete.k.p.offset -= shift >> 9;
-		bch2_btree_iter_set_pos(&del, bkey_start_pos(&delete.k));
-
-		next_pos = insert ? bkey_start_pos(&delete.k) : delete.k.p;
-
-		if (copy.k->k.size != k.k->size) {
-			/* We might end up splitting compressed extents: */
-			unsigned nr_ptrs =
-				bch2_bkey_nr_ptrs_allocated(bkey_i_to_s_c(copy.k));
-
-			ret = bch2_disk_reservation_get(c, &disk_res,
-					copy.k->k.size, nr_ptrs,
-					BCH_DISK_RESERVATION_NOFAIL);
-			BUG_ON(ret);
-		}
-
-		ret =   bch2_btree_iter_traverse(&del) ?:
-			bch2_trans_update(&trans, &del, &delete, trigger_flags) ?:
-			bch2_trans_update(&trans, &dst, copy.k, trigger_flags) ?:
-			bch2_trans_commit(&trans, &disk_res, NULL,
-					  BTREE_INSERT_NOFAIL);
-		bch2_disk_reservation_put(c, &disk_res);
-
-		if (!ret)
-			bch2_btree_iter_set_pos(&src, next_pos);
-	}
-	bch2_trans_iter_exit(&trans, &del);
-	bch2_trans_iter_exit(&trans, &dst);
-	bch2_trans_iter_exit(&trans, &src);
-	bch2_trans_exit(&trans);
-	bch2_bkey_buf_exit(&copy, c);
-
-	if (ret)
-		return ret;
+	ret = bch2_fcollapse_finsert(c, inode_inum(inode), offset >> 9, len >> 9,
+				     insert, &i_sectors_delta);
+	if (!ret && !insert)
+		i_size_write(&inode->v, inode->v.i_size - len);
+	bch2_i_sectors_acct(c, inode, NULL, i_sectors_delta);
 
-	mutex_lock(&inode->ei_update_lock);
-	if (!insert) {
-		i_size_write(&inode->v, new_size);
-		ret = bch2_write_inode_size(c, inode, new_size,
-					    ATTR_MTIME|ATTR_CTIME);
-	} else {
-		/* We need an inode update to update bi_journal_seq for fsync: */
-		ret = bch2_write_inode(c, inode, inode_update_times_fn, NULL,
-				       ATTR_MTIME|ATTR_CTIME);
-	}
-	mutex_unlock(&inode->ei_update_lock);
 	return ret;
 }
 
diff --git a/fs/bcachefs/fs-io.h b/fs/bcachefs/fs-io.h
index bc6e8439d40b..ca70346e68dc 100644
--- a/fs/bcachefs/fs-io.h
+++ b/fs/bcachefs/fs-io.h
@@ -165,7 +165,7 @@ int __must_check bch2_write_inode_size(struct bch_fs *,
 
 int bch2_fsync(struct file *, loff_t, loff_t, int);
 
-int bch2_truncate(struct mnt_idmap *,
+int bchfs_truncate(struct mnt_idmap *,
 		  struct bch_inode_info *, struct iattr *);
 long bch2_fallocate_dispatch(struct file *, int, loff_t, loff_t);
 
diff --git a/fs/bcachefs/fs.c b/fs/bcachefs/fs.c
index 0648874d54f3..0def3a57bd6d 100644
--- a/fs/bcachefs/fs.c
+++ b/fs/bcachefs/fs.c
@@ -798,7 +798,7 @@ static int bch2_setattr(struct mnt_idmap *idmap,
 		return ret;
 
 	return iattr->ia_valid & ATTR_SIZE
-		? bch2_truncate(idmap, inode, iattr)
+		? bchfs_truncate(idmap, inode, iattr)
 		: bch2_setattr_nonsize(idmap, inode, iattr);
 }
 
diff --git a/fs/bcachefs/io_misc.c b/fs/bcachefs/io_misc.c
index c04e5dacfc8d..1afea613df4a 100644
--- a/fs/bcachefs/io_misc.c
+++ b/fs/bcachefs/io_misc.c
@@ -9,7 +9,10 @@
 #include "btree_update.h"
 #include "buckets.h"
 #include "clock.h"
+#include "error.h"
 #include "extents.h"
+#include "extent_update.h"
+#include "inode.h"
 #include "io_misc.h"
 #include "io_write.h"
 #include "subvolume.h"
@@ -213,3 +216,226 @@ int bch2_fpunch(struct bch_fs *c, subvol_inum inum, u64 start, u64 end,
 
 	return ret;
 }
+
+static int truncate_set_isize(struct btree_trans *trans,
+			      subvol_inum inum,
+			      u64 new_i_size)
+{
+	struct btree_iter iter = { NULL };
+	struct bch_inode_unpacked inode_u;
+	int ret;
+
+	ret   = bch2_inode_peek(trans, &iter, &inode_u, inum, BTREE_ITER_INTENT) ?:
+		(inode_u.bi_size = new_i_size, 0) ?:
+		bch2_inode_write(trans, &iter, &inode_u);
+
+	bch2_trans_iter_exit(trans, &iter);
+	return ret;
+}
+
+int bch2_truncate(struct bch_fs *c, subvol_inum inum, u64 new_i_size, u64 *i_sectors_delta)
+{
+	struct btree_trans trans;
+	struct btree_iter fpunch_iter;
+	int ret;
+
+	bch2_trans_init(&trans, c, BTREE_ITER_MAX, 1024);
+	bch2_trans_iter_init(&trans, &fpunch_iter, BTREE_ID_extents,
+			     POS(inum.inum, round_up(new_i_size, block_bytes(c)) >> 9),
+			     BTREE_ITER_INTENT);
+
+	ret = commit_do(&trans, NULL, NULL, BTREE_INSERT_NOFAIL,
+			truncate_set_isize(&trans, inum, new_i_size));
+	if (ret)
+		goto err;
+
+	ret = bch2_fpunch_at(&trans, &fpunch_iter, inum, U64_MAX, i_sectors_delta);
+	if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
+		ret = 0;
+	if (ret)
+		goto err;
+err:
+	bch2_trans_iter_exit(&trans, &fpunch_iter);
+	bch2_trans_exit(&trans);
+
+	bch2_fs_fatal_err_on(ret, c, "%s: error truncating %u:%llu: %s",
+			    __func__, inum.subvol, inum.inum, bch2_err_str(ret));
+	return ret;
+}
+
+static int adjust_i_size(struct btree_trans *trans, subvol_inum inum, u64 offset, s64 len)
+{
+	struct btree_iter iter;
+	struct bch_inode_unpacked inode_u;
+	int ret;
+
+	offset	<<= 9;
+	len	<<= 9;
+
+	ret = bch2_inode_peek(trans, &iter, &inode_u, inum, BTREE_ITER_INTENT);
+	if (ret)
+		return ret;
+
+	if (len > 0) {
+		if (MAX_LFS_FILESIZE - inode_u.bi_size < len) {
+			ret = -EFBIG;
+			goto err;
+		}
+
+		if (offset >= inode_u.bi_size) {
+			ret = -EINVAL;
+			goto err;
+		}
+	}
+
+	inode_u.bi_size += len;
+	inode_u.bi_mtime = inode_u.bi_ctime = bch2_current_time(trans->c);
+
+	ret = bch2_inode_write(trans, &iter, &inode_u);
+err:
+	bch2_trans_iter_exit(trans, &iter);
+	return ret;
+}
+
+int bch2_fcollapse_finsert(struct bch_fs *c, subvol_inum inum,
+			   u64 offset, u64 len, bool insert,
+			   s64 *i_sectors_delta)
+{
+	struct bkey_buf copy;
+	struct btree_trans trans;
+	struct btree_iter src = { NULL }, dst = { NULL }, del = { NULL };
+	s64 shift = insert ? len : -len;
+	int ret = 0;
+
+	bch2_bkey_buf_init(&copy);
+	bch2_trans_init(&trans, c, 0, 1024);
+
+	bch2_trans_iter_init(&trans, &src, BTREE_ID_extents,
+			     POS(inum.inum, U64_MAX),
+			     BTREE_ITER_INTENT);
+	bch2_trans_copy_iter(&dst, &src);
+	bch2_trans_copy_iter(&del, &src);
+
+	if (insert) {
+		ret = commit_do(&trans, NULL, NULL, BTREE_INSERT_NOFAIL,
+				adjust_i_size(&trans, inum, offset, len));
+		if (ret)
+			goto err;
+	} else {
+		bch2_btree_iter_set_pos(&src, POS(inum.inum, offset));
+
+		ret = bch2_fpunch_at(&trans, &src, inum, offset + len, i_sectors_delta);
+		if (ret && !bch2_err_matches(ret, BCH_ERR_transaction_restart))
+			goto err;
+
+		bch2_btree_iter_set_pos(&src, POS(inum.inum, offset + len));
+	}
+
+	while (ret == 0 || bch2_err_matches(ret, BCH_ERR_transaction_restart)) {
+		struct disk_reservation disk_res =
+			bch2_disk_reservation_init(c, 0);
+		struct bkey_i delete;
+		struct bkey_s_c k;
+		struct bpos next_pos;
+		struct bpos move_pos = POS(inum.inum, offset);
+		struct bpos atomic_end;
+		unsigned trigger_flags = 0;
+		u32 snapshot;
+
+		bch2_trans_begin(&trans);
+
+		ret = bch2_subvolume_get_snapshot(&trans, inum.subvol, &snapshot);
+		if (ret)
+			continue;
+
+		bch2_btree_iter_set_snapshot(&src, snapshot);
+		bch2_btree_iter_set_snapshot(&dst, snapshot);
+		bch2_btree_iter_set_snapshot(&del, snapshot);
+
+		bch2_trans_begin(&trans);
+
+		k = insert
+			? bch2_btree_iter_peek_prev(&src)
+			: bch2_btree_iter_peek_upto(&src, POS(inum.inum, U64_MAX));
+		if ((ret = bkey_err(k)))
+			continue;
+
+		if (!k.k || k.k->p.inode != inum.inum)
+			break;
+
+		if (insert &&
+		    bkey_le(k.k->p, POS(inum.inum, offset)))
+			break;
+reassemble:
+		bch2_bkey_buf_reassemble(&copy, c, k);
+
+		if (insert &&
+		    bkey_lt(bkey_start_pos(k.k), move_pos))
+			bch2_cut_front(move_pos, copy.k);
+
+		copy.k->k.p.offset += shift;
+		bch2_btree_iter_set_pos(&dst, bkey_start_pos(&copy.k->k));
+
+		ret = bch2_extent_atomic_end(&trans, &dst, copy.k, &atomic_end);
+		if (ret)
+			continue;
+
+		if (!bkey_eq(atomic_end, copy.k->k.p)) {
+			if (insert) {
+				move_pos = atomic_end;
+				move_pos.offset -= shift;
+				goto reassemble;
+			} else {
+				bch2_cut_back(atomic_end, copy.k);
+			}
+		}
+
+		bkey_init(&delete.k);
+		delete.k.p = copy.k->k.p;
+		delete.k.size = copy.k->k.size;
+		delete.k.p.offset -= shift;
+		bch2_btree_iter_set_pos(&del, bkey_start_pos(&delete.k));
+
+		next_pos = insert ? bkey_start_pos(&delete.k) : delete.k.p;
+
+		if (copy.k->k.size != k.k->size) {
+			/* We might end up splitting compressed extents: */
+			unsigned nr_ptrs =
+				bch2_bkey_nr_ptrs_allocated(bkey_i_to_s_c(copy.k));
+
+			ret = bch2_disk_reservation_get(c, &disk_res,
+					copy.k->k.size, nr_ptrs,
+					BCH_DISK_RESERVATION_NOFAIL);
+			BUG_ON(ret);
+		}
+
+		ret =   bch2_btree_iter_traverse(&del) ?:
+			bch2_trans_update(&trans, &del, &delete, trigger_flags) ?:
+			bch2_trans_update(&trans, &dst, copy.k, trigger_flags) ?:
+			bch2_trans_commit(&trans, &disk_res, NULL,
+					  BTREE_INSERT_NOFAIL);
+		bch2_disk_reservation_put(c, &disk_res);
+
+		if (!ret)
+			bch2_btree_iter_set_pos(&src, next_pos);
+	}
+
+	if (ret && !bch2_err_matches(ret, BCH_ERR_transaction_restart))
+		goto err;
+
+	if (!insert) {
+		ret = commit_do(&trans, NULL, NULL, BTREE_INSERT_NOFAIL,
+				adjust_i_size(&trans, inum, offset, -len));
+	} else {
+		/* We need an inode update to update bi_journal_seq for fsync: */
+		ret = commit_do(&trans, NULL, NULL, BTREE_INSERT_NOFAIL,
+				adjust_i_size(&trans, inum, 0, 0));
+	}
+err:
+	bch2_trans_iter_exit(&trans, &del);
+	bch2_trans_iter_exit(&trans, &dst);
+	bch2_trans_iter_exit(&trans, &src);
+	bch2_trans_exit(&trans);
+	bch2_bkey_buf_exit(&copy, c);
+	return ret;
+}
diff --git a/fs/bcachefs/io_misc.h b/fs/bcachefs/io_misc.h
index 46e9ce3251d6..894a7a04ba4b 100644
--- a/fs/bcachefs/io_misc.h
+++ b/fs/bcachefs/io_misc.h
@@ -9,4 +9,7 @@ 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 *);
 
+int bch2_truncate(struct bch_fs *, subvol_inum, u64, u64 *);
+int bch2_fcollapse_finsert(struct bch_fs *, subvol_inum, u64, u64, bool, s64 *);
+
 #endif /* _BCACHEFS_IO_MISC_H */