merged the two into cifs-2.6.git for-next pending additional testing
and review (added Cc: stable as well)
On Thu, Nov 30, 2023 at 6:22 PM David Howells <dhowells@xxxxxxxxxx> wrote:
>
> Fix a number of issues in the cifs filesystem implementation of the FICLONE
> ioctl in cifs_remap_file_range(). This is analogous to the previously
> fixed bug in cifs_file_copychunk_range() and can share the helper
> functions.
>
> Firstly, the invalidation of the destination range is handled incorrectly:
> We shouldn't just invalidate the whole file as dirty data in the file may
> get lost and we can't just call truncate_inode_pages_range() to invalidate
> the destination range as that will erase parts of a partial folio at each
> end whilst invalidating and discarding all the folios in the middle. We
> need to force all the folios covering the range to be reloaded, but we
> mustn't lose dirty data in them that's not in the destination range.
>
> Further, we shouldn't simply round out the range to PAGE_SIZE at each end
> as cifs should move to support multipage folios.
>
> Secondly, there's an issue whereby a write may have extended the file
> locally, but not have been written back yet. This can leaves the local
> idea of the EOF at a later point than the server's EOF. If a clone request
> is issued, this will fail on the server with STATUS_INVALID_VIEW_SIZE
> (which gets translated to -EIO locally) if the clone source extends past
> the server's EOF.
>
> Fix this by:
>
> (0) Flush the source region (already done). The flush does nothing and
> the EOF isn't moved if the source region has no dirty data.
>
> (1) Move the EOF to the end of the source region if it isn't already at
> least at this point. If we can't do this, for instance if the server
> doesn't support it, just flush the entire source file.
>
> (2) Find the folio (if present) at each end of the range, flushing it and
> increasing the region-to-be-invalidated to cover those in their
> entirety.
>
> (3) Fully discard all the folios covering the range as we want them to be
> reloaded.
>
> (4) Then perform the extent duplication.
>
> Thirdly, set i_size after doing the duplicate_extents operation as this
> value may be used by various things internally. stat() hides the issue
> because setting ->time to 0 causes cifs_getatr() to revalidate the
> attributes.
>
> These were causing the cifs/001 xfstest to fail.
>
> Fixes: 04b38d601239 ("vfs: pull btrfs clone API to vfs layer")
> Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
> cc: Steve French <sfrench@xxxxxxxxx>
> cc: Christoph Hellwig <hch@xxxxxx>
> cc: Paulo Alcantara <pc@xxxxxxxxxxxxx>
> cc: Shyam Prasad N <nspmangalore@xxxxxxxxx>
> cc: Rohith Surabattula <rohiths.msft@xxxxxxxxx>
> cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
> cc: Jeff Layton <jlayton@xxxxxxxxxx>
> cc: linux-cifs@xxxxxxxxxxxxxxx
> cc: linux-mm@xxxxxxxxx
> ---
> fs/smb/client/cifsfs.c | 68 +++++++++++++++++++++++++++++++++++-------
> 1 file changed, 57 insertions(+), 11 deletions(-)
>
> diff --git a/fs/smb/client/cifsfs.c b/fs/smb/client/cifsfs.c
> index 8097a9b3e98c..c5fc0a35bb19 100644
> --- a/fs/smb/client/cifsfs.c
> +++ b/fs/smb/client/cifsfs.c
> @@ -1268,9 +1268,12 @@ static loff_t cifs_remap_file_range(struct file *src_file, loff_t off,
> {
> struct inode *src_inode = file_inode(src_file);
> struct inode *target_inode = file_inode(dst_file);
> + struct cifsInodeInfo *src_cifsi = CIFS_I(src_inode);
> + struct cifsInodeInfo *target_cifsi = CIFS_I(target_inode);
> struct cifsFileInfo *smb_file_src = src_file->private_data;
> - struct cifsFileInfo *smb_file_target;
> - struct cifs_tcon *target_tcon;
> + struct cifsFileInfo *smb_file_target = dst_file->private_data;
> + struct cifs_tcon *target_tcon, *src_tcon;
> + unsigned long long destend, fstart, fend, new_size;
> unsigned int xid;
> int rc;
>
> @@ -1281,13 +1284,13 @@ static loff_t cifs_remap_file_range(struct file *src_file, loff_t off,
>
> xid = get_xid();
>
> - if (!src_file->private_data || !dst_file->private_data) {
> + if (!smb_file_src || !smb_file_target) {
> rc = -EBADF;
> cifs_dbg(VFS, "missing cifsFileInfo on copy range src file\n");
> goto out;
> }
>
> - smb_file_target = dst_file->private_data;
> + src_tcon = tlink_tcon(smb_file_src->tlink);
> target_tcon = tlink_tcon(smb_file_target->tlink);
>
> /*
> @@ -1300,20 +1303,63 @@ static loff_t cifs_remap_file_range(struct file *src_file, loff_t off,
> if (len == 0)
> len = src_inode->i_size - off;
>
> - cifs_dbg(FYI, "about to flush pages\n");
> - /* should we flush first and last page first */
> - truncate_inode_pages_range(&target_inode->i_data, destoff,
> - PAGE_ALIGN(destoff + len)-1);
> + cifs_dbg(FYI, "clone range\n");
> +
> + /* Flush the source buffer */
> + rc = filemap_write_and_wait_range(src_inode->i_mapping, off,
> + off + len - 1);
> + if (rc)
> + goto unlock;
> +
> + /* The server-side copy will fail if the source crosses the EOF marker.
> + * Advance the EOF marker after the flush above to the end of the range
> + * if it's short of that.
> + */
> + if (src_cifsi->netfs.remote_i_size < off + len) {
> + rc = cifs_precopy_set_eof(src_inode, src_cifsi, src_tcon, xid, off + len);
> + if (rc < 0)
> + goto unlock;
> + }
> +
> + new_size = destoff + len;
> + destend = destoff + len - 1;
>
> - if (target_tcon->ses->server->ops->duplicate_extents)
> + /* Flush the folios at either end of the destination range to prevent
> + * accidental loss of dirty data outside of the range.
> + */
> + fstart = destoff;
> + fend = destend;
> +
> + rc = cifs_flush_folio(target_inode, destoff, &fstart, &fend, true);
> + if (rc)
> + goto unlock;
> + rc = cifs_flush_folio(target_inode, destend, &fstart, &fend, false);
> + if (rc)
> + goto unlock;
> +
> + /* Discard all the folios that overlap the destination region. */
> + cifs_dbg(FYI, "about to discard pages %llx-%llx\n", fstart, fend);
> + truncate_inode_pages_range(&target_inode->i_data, fstart, fend);
> +
> + fscache_invalidate(cifs_inode_cookie(target_inode), NULL,
> + i_size_read(target_inode), 0);
> +
> + rc = -EOPNOTSUPP;
> + if (target_tcon->ses->server->ops->duplicate_extents) {
> rc = target_tcon->ses->server->ops->duplicate_extents(xid,
> smb_file_src, smb_file_target, off, len, destoff);
> - else
> - rc = -EOPNOTSUPP;
> + if (rc == 0 && new_size > i_size_read(target_inode)) {
> + truncate_setsize(target_inode, new_size);
> + netfs_resize_file(&target_cifsi->netfs, new_size);
> + fscache_resize_cookie(cifs_inode_cookie(target_inode),
> + new_size);
> + }
> + }
>
> /* force revalidate of size and timestamps of target file now
> that target is updated on the server */
> CIFS_I(target_inode)->time = 0;
> +unlock:
> /* although unlocking in the reverse order from locking is not
> strictly necessary here it is a little cleaner to be consistent */
> unlock_two_nondirectories(src_inode, target_inode);
>
>
--
Thanks,
Steve
