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Commit 9998eb70 authored by Chris Mason's avatar Chris Mason
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Btrfs: fix reservations in btrfs_page_mkwrite 



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: default avatarChris Mason <chris.mason@oracle.com>
parent 9b230628

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;

}