On 11/01/2012 12:58 AM, Darrick J. Wong wrote:
> Fix up the filesystems that provide their own ->page_mkwrite handlers to
> provide stable page writes if necessary.
>
> Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
> ---
> fs/9p/vfs_file.c | 1 +
> fs/afs/write.c | 4 ++--
> fs/ceph/addr.c | 1 +
> fs/cifs/file.c | 1 +
> fs/ocfs2/mmap.c | 1 +
> fs/ubifs/file.c | 4 ++--
> 6 files changed, 8 insertions(+), 4 deletions(-)
>
>
> diff --git a/fs/9p/vfs_file.c b/fs/9p/vfs_file.c
> index c2483e9..aa253f0 100644
> --- a/fs/9p/vfs_file.c
> +++ b/fs/9p/vfs_file.c
> @@ -620,6 +620,7 @@ v9fs_vm_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
> lock_page(page);
> if (page->mapping != inode->i_mapping)
> goto out_unlock;
> + wait_on_stable_page_write(page);
>
Good god thanks, yes please ;-)
> return VM_FAULT_LOCKED;
> out_unlock:
> diff --git a/fs/afs/write.c b/fs/afs/write.c
> index 9aa52d9..39eb2a4 100644
> --- a/fs/afs/write.c
> +++ b/fs/afs/write.c
> @@ -758,7 +758,7 @@ int afs_page_mkwrite(struct vm_area_struct *vma, struct page *page)
afs, is it not a network filesystem? which means that it has it's own emulated none-block-device
BDI, registered internally. So if you do need stable pages someone should call
bdi_require_stable_pages()
But again since it is a network filesystem I don't see how it is needed, and/or it might be
taken care of already.
> #ifdef CONFIG_AFS_FSCACHE
> fscache_wait_on_page_write(vnode->cache, page);
> #endif
> -
> + wait_on_stable_page_write(page);
> _leave(" = 0");
> - return 0;
> + return VM_FAULT_LOCKED;
> }
> diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
CEPH for sure has it's own "emulated none-block-device BDI". This one is also
a pure networking filesystem.
And it already does what it needs to do with wait_on_writeback().
So i do not think you should touch CEPH
> index 6690269..e9734bf 100644
> --- a/fs/ceph/addr.c
> +++ b/fs/ceph/addr.c
> @@ -1208,6 +1208,7 @@ static int ceph_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
> set_page_dirty(page);
> up_read(&mdsc->snap_rwsem);
> ret = VM_FAULT_LOCKED;
> + wait_on_stable_page_write(page);
> } else {
> if (ret == -ENOMEM)
> ret = VM_FAULT_OOM;
> diff --git a/fs/cifs/file.c b/fs/cifs/file.c
Cifs also self-BDI network filesystem, but
> index edb25b4..a8770bf 100644
> --- a/fs/cifs/file.c
> +++ b/fs/cifs/file.c
> @@ -2997,6 +2997,7 @@ cifs_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
> struct page *page = vmf->page;
>
> lock_page(page);
It waits by locking the page, that's cifs naive way of waiting for writeback
> + wait_on_stable_page_write(page);
Instead it could do better and not override page_mkwrite at all, and all it needs
to do is call bdi_require_stable_pages() at it's own registered BDI
> return VM_FAULT_LOCKED;
> }
>
> diff --git a/fs/ocfs2/mmap.c b/fs/ocfs2/mmap.c
> index 47a87dd..a0027b1 100644
> --- a/fs/ocfs2/mmap.c
> +++ b/fs/ocfs2/mmap.c
> @@ -124,6 +124,7 @@ static int __ocfs2_page_mkwrite(struct file *file, struct buffer_head *di_bh,
> fsdata);
> BUG_ON(ret != len);
> ret = VM_FAULT_LOCKED;
> + wait_on_stable_page_write(page);
> out:
> return ret;
> }
> diff --git a/fs/ubifs/file.c b/fs/ubifs/file.c
> index 5bc7781..cb0d3aa 100644
> --- a/fs/ubifs/file.c
> +++ b/fs/ubifs/file.c
> @@ -1522,8 +1522,8 @@ static int ubifs_vm_page_mkwrite(struct vm_area_struct *vma,
> ubifs_release_dirty_inode_budget(c, ui);
> }
>
> - unlock_page(page);
> - return 0;
> + wait_on_stable_page_write(page);
ubifs has it's special ubi block device. So someone needs to call bdi_require_stable_pages()
for this to work.
I think that here too. The existing code, like cifs, calls page_lock, as a way of
waiting for writeback.
So this is certainly not finished.
> + return VM_FAULT_LOCKED;
>
> out_unlock:
> unlock_page(page);
>
Cheers
Boaz
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