bcachefs: Truncate/fpunch now works on block boundaries, not page

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

diff --git a/fs/bcachefs/fs-io.c b/fs/bcachefs/fs-io.c
index f1eb9b902db9d9857d1d80b6d0408b6e174122f4..913e26487efb1e6e5aaa6cd2e674fdc63cc04054 100644 (file)
--- a/fs/bcachefs/fs-io.c
+++ b/fs/bcachefs/fs-io.c
@@ -2324,8 +2324,10 @@ static int __bch2_truncate_page(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 bch_page_state *s;
        unsigned start_offset = start & (PAGE_SIZE - 1);
        unsigned end_offset = ((end - 1) & (PAGE_SIZE - 1)) + 1;
+       unsigned i;
        struct page *page;
        int ret = 0;
 
@@ -2357,12 +2359,32 @@ static int __bch2_truncate_page(struct bch_inode_info *inode,
                }
        }
 
+       s = bch2_page_state_create(page, 0);
+       if (!s) {
+               ret = -ENOMEM;
+               goto unlock;
+       }
+
        if (!PageUptodate(page)) {
                ret = bch2_read_single_page(page, mapping);
                if (ret)
                        goto unlock;
        }
 
+       if (index != start >> PAGE_SHIFT)
+               start_offset = 0;
+       if (index != end >> PAGE_SHIFT)
+               end_offset = PAGE_SIZE;
+
+       for (i = round_up(start_offset, block_bytes(c)) >> 9;
+            i < round_down(end_offset, block_bytes(c)) >> 9;
+            i++) {
+               s->s[i].nr_replicas     = 0;
+               s->s[i].state           = SECTOR_UNALLOCATED;
+       }
+
+       zero_user_segment(page, start_offset, end_offset);
+
        /*
         * Bit of a hack - we don't want truncate to fail due to -ENOSPC.
         *
@@ -2372,14 +2394,6 @@ static int __bch2_truncate_page(struct bch_inode_info *inode,
        ret = bch2_get_page_disk_reservation(c, inode, page, false);
        BUG_ON(ret);
 
-       if (index == start >> PAGE_SHIFT &&
-           index == end >> PAGE_SHIFT)
-               zero_user_segment(page, start_offset, end_offset);
-       else if (index == start >> PAGE_SHIFT)
-               zero_user_segment(page, start_offset, PAGE_SIZE);
-       else if (index == end >> PAGE_SHIFT)
-               zero_user_segment(page, 0, end_offset);
-
        filemap_dirty_folio(mapping, page_folio(page));
 unlock:
        unlock_page(page);
@@ -2391,7 +2405,7 @@ out:
 static int bch2_truncate_page(struct bch_inode_info *inode, loff_t from)
 {
        return __bch2_truncate_page(inode, from >> PAGE_SHIFT,
-                                   from, from + PAGE_SIZE);
+                                   from, round_up(from, PAGE_SIZE));
 }
 
 static int bch2_extend(struct bch_inode_info *inode, struct iattr *iattr)
@@ -2483,12 +2497,8 @@ int bch2_truncate(struct bch_inode_info *inode, struct iattr *iattr)
 
        truncate_setsize(&inode->v, iattr->ia_size);
 
-       /*
-        * XXX: need a comment explaining why PAGE_SIZE and not block_bytes()
-        * here:
-        */
        ret = __bch2_fpunch(c, inode,
-                       round_up(iattr->ia_size, PAGE_SIZE) >> 9,
+                       round_up(iattr->ia_size, block_bytes(c)) >> 9,
                        U64_MAX, &inode->ei_journal_seq);
        if (unlikely(ret))
                goto err;
@@ -2510,8 +2520,8 @@ err:
 static long bch2_fpunch(struct bch_inode_info *inode, loff_t offset, loff_t len)
 {
        struct bch_fs *c = inode->v.i_sb->s_fs_info;
-       u64 discard_start = round_up(offset, PAGE_SIZE) >> 9;
-       u64 discard_end = round_down(offset + len, PAGE_SIZE) >> 9;
+       u64 discard_start = round_up(offset, block_bytes(c)) >> 9;
+       u64 discard_end = round_down(offset + len, block_bytes(c)) >> 9;
        int ret = 0;
 
        inode_lock(&inode->v);
@@ -2596,7 +2606,7 @@ static long bch2_fcollapse(struct bch_inode_info *inode,
 
        while (bkey_cmp(dst->pos,
                        POS(inode->v.i_ino,
-                           round_up(new_size, PAGE_SIZE) >> 9)) < 0) {
+                           round_up(new_size, block_bytes(c)) >> 9)) < 0) {
                struct disk_reservation disk_res;
 
                ret = bch2_btree_iter_traverse(dst);
@@ -2671,8 +2681,9 @@ static long bch2_fallocate(struct bch_inode_info *inode, int mode,
        struct btree_trans trans;
        struct btree_iter *iter;
        struct bpos end_pos;
-       loff_t block_start, block_end;
-       loff_t end = offset + len;
+       loff_t end              = offset + len;
+       loff_t block_start      = round_down(offset,    block_bytes(c));
+       loff_t block_end        = round_up(end,         block_bytes(c));
        unsigned sectors;
        unsigned replicas = io_opts(c, inode).data_replicas;
        int ret;
@@ -2704,12 +2715,6 @@ static long bch2_fallocate(struct bch_inode_info *inode, int mode,
                        goto err;
 
                truncate_pagecache_range(&inode->v, offset, end - 1);
-
-               block_start     = round_up(offset, PAGE_SIZE);
-               block_end       = round_down(end, PAGE_SIZE);
-       } else {
-               block_start     = round_down(offset, PAGE_SIZE);
-               block_end       = round_up(end, PAGE_SIZE);
        }
 
        iter = bch2_trans_get_iter(&trans, BTREE_ID_EXTENTS,