bcachefs: Refactor bchfs_fallocate() to not nest btree_trans on stack

Upcoming patch is going to disallow multiple btree_trans on the stack.

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

diff --git a/fs/bcachefs/fs-io.c b/fs/bcachefs/fs-io.c
index 8891207c46a95a84389b4e178527a61dc07d3d7a..a7cd85647354fe5dd09b39f0c43982145d0c9cdd 100644 (file)
--- a/fs/bcachefs/fs-io.c
+++ b/fs/bcachefs/fs-io.c
@@ -2633,54 +2633,21 @@ err:
        return ret;
 }
 
-static long bchfs_fallocate(struct bch_inode_info *inode, int mode,
-                           loff_t offset, loff_t len)
+static int __bchfs_fallocate(struct bch_inode_info *inode, int mode,
+                            u64 start_sector, u64 end_sector)
 {
-       struct address_space *mapping = inode->v.i_mapping;
        struct bch_fs *c = inode->v.i_sb->s_fs_info;
        struct btree_trans trans;
        struct btree_iter *iter;
-       struct bpos end_pos;
-       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;
+       struct bpos end_pos = POS(inode->v.i_ino, end_sector);
        unsigned replicas = io_opts(c, &inode->ei_inode).data_replicas;
-       int ret;
+       int ret = 0;
 
        bch2_trans_init(&trans, c, BTREE_ITER_MAX, 0);
 
-       inode_lock(&inode->v);
-       inode_dio_wait(&inode->v);
-       bch2_pagecache_block_get(&inode->ei_pagecache_lock);
-
-       if (!(mode & FALLOC_FL_KEEP_SIZE) && end > inode->v.i_size) {
-               ret = inode_newsize_ok(&inode->v, end);
-               if (ret)
-                       goto err;
-       }
-
-       if (mode & FALLOC_FL_ZERO_RANGE) {
-               ret = __bch2_truncate_page(inode,
-                                          offset >> PAGE_SHIFT,
-                                          offset, end);
-
-               if (!ret &&
-                   offset >> PAGE_SHIFT != end >> PAGE_SHIFT)
-                       ret = __bch2_truncate_page(inode,
-                                                  end >> PAGE_SHIFT,
-                                                  offset, end);
-
-               if (unlikely(ret))
-                       goto err;
-
-               truncate_pagecache_range(&inode->v, offset, end - 1);
-       }
-
        iter = bch2_trans_get_iter(&trans, BTREE_ID_extents,
-                       POS(inode->v.i_ino, block_start >> 9),
+                       POS(inode->v.i_ino, start_sector),
                        BTREE_ITER_SLOTS|BTREE_ITER_INTENT);
-       end_pos = POS(inode->v.i_ino, block_end >> 9);
 
        while (!ret && bkey_cmp(iter->pos, end_pos) < 0) {
                s64 i_sectors_delta = 0;
@@ -2688,6 +2655,7 @@ static long bchfs_fallocate(struct bch_inode_info *inode, int mode,
                struct quota_res quota_res = { 0 };
                struct bkey_i_reservation reservation;
                struct bkey_s_c k;
+               unsigned sectors;
 
                bch2_trans_begin(&trans);
 
@@ -2748,7 +2716,48 @@ bkey_err:
                        ret = 0;
        }
        bch2_trans_iter_put(&trans, iter);
+       bch2_trans_exit(&trans);
+       return ret;
+}
 
+static long bchfs_fallocate(struct bch_inode_info *inode, int mode,
+                           loff_t offset, loff_t len)
+{
+       struct address_space *mapping = inode->v.i_mapping;
+       struct bch_fs *c = inode->v.i_sb->s_fs_info;
+       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));
+       int ret;
+
+       inode_lock(&inode->v);
+       inode_dio_wait(&inode->v);
+       bch2_pagecache_block_get(&inode->ei_pagecache_lock);
+
+       if (!(mode & FALLOC_FL_KEEP_SIZE) && end > inode->v.i_size) {
+               ret = inode_newsize_ok(&inode->v, end);
+               if (ret)
+                       goto err;
+       }
+
+       if (mode & FALLOC_FL_ZERO_RANGE) {
+               ret = __bch2_truncate_page(inode,
+                                          offset >> PAGE_SHIFT,
+                                          offset, end);
+
+               if (!ret &&
+                   offset >> PAGE_SHIFT != end >> PAGE_SHIFT)
+                       ret = __bch2_truncate_page(inode,
+                                                  end >> PAGE_SHIFT,
+                                                  offset, end);
+
+               if (unlikely(ret))
+                       goto err;
+
+               truncate_pagecache_range(&inode->v, offset, end - 1);
+       }
+
+       ret = __bchfs_fallocate(inode, mode, block_start >> 9, block_end >> 9);
        if (ret)
                goto err;
 
@@ -2762,28 +2771,13 @@ bkey_err:
        if (end >= inode->v.i_size &&
            (!(mode & FALLOC_FL_KEEP_SIZE) ||
             (mode & FALLOC_FL_ZERO_RANGE))) {
-               struct btree_iter *inode_iter;
-               struct bch_inode_unpacked inode_u;
-
-               do {
-                       bch2_trans_begin(&trans);
-                       inode_iter = bch2_inode_peek(&trans, &inode_u,
-                                                    inode->v.i_ino, 0);
-                       ret = PTR_ERR_OR_ZERO(inode_iter);
-               } while (ret == -EINTR);
-
-               bch2_trans_iter_put(&trans, inode_iter);
-               bch2_trans_unlock(&trans);
-
-               if (ret)
-                       goto err;
 
                /*
                 * Sync existing appends before extending i_size,
                 * as in bch2_extend():
                 */
                ret = filemap_write_and_wait_range(mapping,
-                                       inode_u.bi_size, S64_MAX);
+                                       inode->ei_inode.bi_size, S64_MAX);
                if (ret)
                        goto err;
 
@@ -2797,7 +2791,6 @@ bkey_err:
                mutex_unlock(&inode->ei_update_lock);
        }
 err:
-       bch2_trans_exit(&trans);
        bch2_pagecache_block_put(&inode->ei_pagecache_lock);
        inode_unlock(&inode->v);
        return ret;