Btrfs: fix reservations in btrfs_page_mkwrite (9998eb70) · Commits · 戴 / test

Josef fixed btrfs_page_mkwrite to properly release reserved extents if there was an error. But if we fail to get a reservation and we fail to dirty the inode (for ENOSPC reasons), we'll end up trying to release a reservation we never had. This makes sure we only release if we were able to reserve. Signed-off-by:

Chris Mason <chris.mason@oracle.com>

fs/btrfs/inode.c

+8 −2

Original line number	Diff line number	Diff line
		@@ -6401,18 +6401,23 @@ int btrfs_page_mkwrite(struct vm_area_struct vma, struct vm_fault vmf)
		unsigned long zero_start;
		loff_t size;
		int ret;
		int reserved = 0;
		u64 page_start;
		u64 page_end;

		ret = btrfs_delalloc_reserve_space(inode, PAGE_CACHE_SIZE);
		if (!ret)
		if (!ret) {
		ret = btrfs_update_time(vma->vm_file);
		reserved = 1;
		}
		if (ret) {
		if (ret == -ENOMEM)
		ret = VM_FAULT_OOM;
		else /* -ENOSPC, -EIO, etc */
		ret = VM_FAULT_SIGBUS;
		if (reserved)
		goto out;
		goto out_noreserve;
		}

		ret = VM_FAULT_NOPAGE; /* make the VM retry the fault */
		@@ -6495,6 +6500,7 @@ out_unlock:
		unlock_page(page);
		out:
		btrfs_delalloc_release_space(inode, PAGE_CACHE_SIZE);
		out_noreserve:
		return ret;
		}

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