[16/21] btrfs: lock extent before pages in encoded write

Commit Message

Goldwyn Rodrigues March 2, 2023, 10:25 p.m. UTC

From: Goldwyn Rodrigues <[e-mail]>

Lock the extent range while performing direct encoded writes, as opposed
to individual pages.

Signed-off-by: Goldwyn Rodrigues <[e-mail]>
Reviewed-by: Josef Bacik <[e-mail]>
---
 fs/btrfs/inode.c | 52 +++++++++++++++++++++++++-----------------------
 1 file changed, 27 insertions(+), 25 deletions(-)

Patch

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 729def5969d8..70cf852a3efd 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -10289,37 +10289,18 @@  ssize_t btrfs_do_encoded_write(struct kiocb *iocb, struct iov_iter *from,
 	pages = kvcalloc(nr_pages, sizeof(struct page *), GFP_KERNEL_ACCOUNT);
 	if (!pages)
 		return -ENOMEM;
-	for (i = 0; i < nr_pages; i++) {
-		size_t bytes = min_t(size_t, PAGE_SIZE, iov_iter_count(from));
-		char *kaddr;
-
-		pages[i] = alloc_page(GFP_KERNEL_ACCOUNT);
-		if (!pages[i]) {
-			ret = -ENOMEM;
-			goto out_pages;
-		}
-		kaddr = kmap_local_page(pages[i]);
-		if (copy_from_iter(kaddr, bytes, from) != bytes) {
-			kunmap_local(kaddr);
-			ret = -EFAULT;
-			goto out_pages;
-		}
-		if (bytes < PAGE_SIZE)
-			memset(kaddr + bytes, 0, PAGE_SIZE - bytes);
-		kunmap_local(kaddr);
-	}
 
 	for (;;) {
 		struct btrfs_ordered_extent *ordered;
 
 		ret = btrfs_wait_ordered_range(&inode->vfs_inode, start, num_bytes);
 		if (ret)
-			goto out_pages;
+			goto out;
 		ret = invalidate_inode_pages2_range(inode->vfs_inode.i_mapping,
 						    start >> PAGE_SHIFT,
 						    end >> PAGE_SHIFT);
 		if (ret)
-			goto out_pages;
+			goto out;
 		lock_extent(io_tree, start, end, &cached_state);
 		ordered = btrfs_lookup_ordered_range(inode, start, num_bytes);
 		if (!ordered &&
@@ -10331,6 +10312,26 @@  ssize_t btrfs_do_encoded_write(struct kiocb *iocb, struct iov_iter *from,
 		cond_resched();
 	}
 
+	for (i = 0; i < nr_pages; i++) {
+		size_t bytes = min_t(size_t, PAGE_SIZE, iov_iter_count(from));
+		char *kaddr;
+
+		pages[i] = alloc_page(GFP_KERNEL_ACCOUNT);
+		if (!pages[i]) {
+			ret = -ENOMEM;
+			goto out_pages;
+		}
+		kaddr = kmap_local_page(pages[i]);
+		if (copy_from_iter(kaddr, bytes, from) != bytes) {
+			kunmap_local(kaddr);
+			ret = -EFAULT;
+			goto out_pages;
+		}
+		if (bytes < PAGE_SIZE)
+			memset(kaddr + bytes, 0, PAGE_SIZE - bytes);
+		kunmap_local(kaddr);
+	}
+
 	/*
 	 * We don't use the higher-level delalloc space functions because our
 	 * num_bytes and disk_num_bytes are different.
@@ -10389,8 +10390,6 @@  ssize_t btrfs_do_encoded_write(struct kiocb *iocb, struct iov_iter *from,
 	if (start + encoded->len > inode->vfs_inode.i_size)
 		i_size_write(&inode->vfs_inode, start + encoded->len);
 
-	unlock_extent(io_tree, start, end, &cached_state);
-
 	btrfs_delalloc_release_extents(inode, num_bytes);
 
 	if (btrfs_submit_compressed_write(inode, start, num_bytes, ins.objectid,
@@ -10400,6 +10399,9 @@  ssize_t btrfs_do_encoded_write(struct kiocb *iocb, struct iov_iter *from,
 		ret = -EIO;
 		goto out_pages;
 	}
+
+	unlock_extent(io_tree, start, end, &cached_state);
+
 	ret = orig_count;
 	goto out;
 
@@ -10419,14 +10421,14 @@  ssize_t btrfs_do_encoded_write(struct kiocb *iocb, struct iov_iter *from,
 	 */
 	if (!extent_reserved)
 		btrfs_free_reserved_data_space_noquota(fs_info, disk_num_bytes);
-out_unlock:
-	unlock_extent(io_tree, start, end, &cached_state);
 out_pages:
 	for (i = 0; i < nr_pages; i++) {
 		if (pages[i])
 			__free_page(pages[i]);
 	}
 	kvfree(pages);
+out_unlock:
+	unlock_extent(io_tree, start, end, &cached_state);
 out:
 	if (ret >= 0)
 		iocb->ki_pos += encoded->len;