From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5B4DCC282C4 for ; Mon, 4 Feb 2019 16:57:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2B59F20815 for ; Mon, 4 Feb 2019 16:57:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730348AbfBDQ5E (ORCPT ); Mon, 4 Feb 2019 11:57:04 -0500 Received: from mx2.suse.de ([195.135.220.15]:47498 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727308AbfBDQ5E (ORCPT ); Mon, 4 Feb 2019 11:57:04 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id CF0C7AC8D for ; Mon, 4 Feb 2019 16:57:02 +0000 (UTC) Subject: Re: [PATCH 14/15] btrfs: Implement find_first_clear_extent_bit To: linux-btrfs@vger.kernel.org Cc: jeffm@suse.com References: <20190130145102.4708-1-nborisov@suse.com> <20190130145102.4708-15-nborisov@suse.com> From: Nikolay Borisov Openpgp: preference=signencrypt Autocrypt: addr=nborisov@suse.com; prefer-encrypt=mutual; keydata= mQINBFiKBz4BEADNHZmqwhuN6EAzXj9SpPpH/nSSP8YgfwoOqwrP+JR4pIqRK0AWWeWCSwmZ T7g+RbfPFlmQp+EwFWOtABXlKC54zgSf+uulGwx5JAUFVUIRBmnHOYi/lUiE0yhpnb1KCA7f u/W+DkwGerXqhhe9TvQoGwgCKNfzFPZoM+gZrm+kWv03QLUCr210n4cwaCPJ0Nr9Z3c582xc bCUVbsjt7BN0CFa2BByulrx5xD9sDAYIqfLCcZetAqsTRGxM7LD0kh5WlKzOeAXj5r8DOrU2 GdZS33uKZI/kZJZVytSmZpswDsKhnGzRN1BANGP8sC+WD4eRXajOmNh2HL4P+meO1TlM3GLl EQd2shHFY0qjEo7wxKZI1RyZZ5AgJnSmehrPCyuIyVY210CbMaIKHUIsTqRgY5GaNME24w7h TyyVCy2qAM8fLJ4Vw5bycM/u5xfWm7gyTb9V1TkZ3o1MTrEsrcqFiRrBY94Rs0oQkZvunqia c+NprYSaOG1Cta14o94eMH271Kka/reEwSZkC7T+o9hZ4zi2CcLcY0DXj0qdId7vUKSJjEep c++s8ncFekh1MPhkOgNj8pk17OAESanmDwksmzh1j12lgA5lTFPrJeRNu6/isC2zyZhTwMWs k3LkcTa8ZXxh0RfWAqgx/ogKPk4ZxOXQEZetkEyTFghbRH2BIwARAQABtCNOaWtvbGF5IEJv cmlzb3YgPG5ib3Jpc292QHN1c2UuY29tPokCOAQTAQIAIgUCWIo48QIbAwYLCQgHAwIGFQgC CQoLBBYCAwECHgECF4AACgkQcb6CRuU/KFc0eg/9GLD3wTQz9iZHMFbjiqTCitD7B6dTLV1C ddZVlC8Hm/TophPts1bWZORAmYIihHHI1EIF19+bfIr46pvfTu0yFrJDLOADMDH+Ufzsfy2v HSqqWV/nOSWGXzh8bgg/ncLwrIdEwBQBN9SDS6aqsglagvwFD91UCg/TshLlRxD5BOnuzfzI Leyx2c6YmH7Oa1R4MX9Jo79SaKwdHt2yRN3SochVtxCyafDlZsE/efp21pMiaK1HoCOZTBp5 VzrIP85GATh18pN7YR9CuPxxN0V6IzT7IlhS4Jgj0NXh6vi1DlmKspr+FOevu4RVXqqcNTSS E2rycB2v6cttH21UUdu/0FtMBKh+rv8+yD49FxMYnTi1jwVzr208vDdRU2v7Ij/TxYt/v4O8 V+jNRKy5Fevca/1xroQBICXsNoFLr10X5IjmhAhqIH8Atpz/89ItS3+HWuE4BHB6RRLM0gy8 T7rN6ja+KegOGikp/VTwBlszhvfLhyoyjXI44Tf3oLSFM+8+qG3B7MNBHOt60CQlMkq0fGXd mm4xENl/SSeHsiomdveeq7cNGpHi6i6ntZK33XJLwvyf00PD7tip/GUj0Dic/ZUsoPSTF/mG EpuQiUZs8X2xjK/AS/l3wa4Kz2tlcOKSKpIpna7V1+CMNkNzaCOlbv7QwprAerKYywPCoOSC 7P25Ag0EWIoHPgEQAMiUqvRBZNvPvki34O/dcTodvLSyOmK/MMBDrzN8Cnk302XfnGlW/YAQ csMWISKKSpStc6tmD+2Y0z9WjyRqFr3EGfH1RXSv9Z1vmfPzU42jsdZn667UxrRcVQXUgoKg QYx055Q2FdUeaZSaivoIBD9WtJq/66UPXRRr4H/+Y5FaUZx+gWNGmBT6a0S/GQnHb9g3nonD jmDKGw+YO4P6aEMxyy3k9PstaoiyBXnzQASzdOi39BgWQuZfIQjN0aW+Dm8kOAfT5i/yk59h VV6v3NLHBjHVw9kHli3jwvsizIX9X2W8tb1SefaVxqvqO1132AO8V9CbE1DcVT8fzICvGi42 FoV/k0QOGwq+LmLf0t04Q0csEl+h69ZcqeBSQcIMm/Ir+NorfCr6HjrB6lW7giBkQl6hhomn l1mtDP6MTdbyYzEiBFcwQD4terc7S/8ELRRybWQHQp7sxQM/Lnuhs77MgY/e6c5AVWnMKd/z MKm4ru7A8+8gdHeydrRQSWDaVbfy3Hup0Ia76J9FaolnjB8YLUOJPdhI2vbvNCQ2ipxw3Y3c KhVIpGYqwdvFIiz0Fej7wnJICIrpJs/+XLQHyqcmERn3s/iWwBpeogrx2Lf8AGezqnv9woq7 OSoWlwXDJiUdaqPEB/HmGfqoRRN20jx+OOvuaBMPAPb+aKJyle8zABEBAAGJAh8EGAECAAkF AliKBz4CGwwACgkQcb6CRuU/KFdacg/+M3V3Ti9JYZEiIyVhqs+yHb6NMI1R0kkAmzsGQ1jU zSQUz9AVMR6T7v2fIETTT/f5Oout0+Hi9cY8uLpk8CWno9V9eR/B7Ifs2pAA8lh2nW43FFwp IDiSuDbH6oTLmiGCB206IvSuaQCp1fed8U6yuqGFcnf0ZpJm/sILG2ECdFK9RYnMIaeqlNQm iZicBY2lmlYFBEaMXHoy+K7nbOuizPWdUKoKHq+tmZ3iA+qL5s6Qlm4trH28/fPpFuOmgP8P K+7LpYLNSl1oQUr+WlqilPAuLcCo5Vdl7M7VFLMq4xxY/dY99aZx0ZJQYFx0w/6UkbDdFLzN upT7NIN68lZRucImffiWyN7CjH23X3Tni8bS9ubo7OON68NbPz1YIaYaHmnVQCjDyDXkQoKC R82Vf9mf5slj0Vlpf+/Wpsv/TH8X32ajva37oEQTkWNMsDxyw3aPSps6MaMafcN7k60y2Wk/ TCiLsRHFfMHFY6/lq/c0ZdOsGjgpIK0G0z6et9YU6MaPuKwNY4kBdjPNBwHreucrQVUdqRRm RcxmGC6ohvpqVGfhT48ZPZKZEWM+tZky0mO7bhZYxMXyVjBn4EoNTsXy1et9Y1dU3HVJ8fod 5UqrNrzIQFbdeM0/JqSLrtlTcXKJ7cYFa9ZM2AP7UIN9n1UWxq+OPY9YMOewVfYtL8M= Message-ID: <0dbc158a-f1d8-47c0-cfbf-b1c5f6f3ff84@suse.com> Date: Mon, 4 Feb 2019 18:57:01 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.2.1 MIME-Version: 1.0 In-Reply-To: <20190130145102.4708-15-nborisov@suse.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On 30.01.19 г. 16:51 ч., Nikolay Borisov wrote: > This function is very similar to find_first_extent_bit except that it > locates the first contiguous span of space which does not have bits set. > It's intended use is in the freespace trimming code. > > Signed-off-by: Nikolay Borisov > --- > fs/btrfs/extent_io.c | 78 ++++++++++++++++++++++++++++++++++++++++++++ > fs/btrfs/extent_io.h | 2 ++ > 2 files changed, 80 insertions(+) > > diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c > index d5525d18803d..542eaab9c0c1 100644 > --- a/fs/btrfs/extent_io.c > +++ b/fs/btrfs/extent_io.c > @@ -1474,6 +1474,84 @@ int find_first_extent_bit(struct extent_io_tree *tree, u64 start, > return ret; > } > > +/* find_first_clear_extent_bit - finds the first range that has @bits not set > + * and that starts after @start > + * > + * @tree - the tree to search > + * @start - the offset at/after which the found extent should start > + * @start_ret - records the beginning of the range > + * @end_ret - records the end of the range (inclusive) > + * @bits - the set of bits which must be unset > + * > + * Returns 0 when a range is found and @start_ret/@end_ret are initialised > + * accordingly, 1 otherwise. Since unallocated range is also considered one > + * which doesn't have the bits set it's possible that @end_ret contains -1, this > + * happens in case the range spans (last_range_end, end of device]. In this case > + * it's up to the caller to trim @end_ret to the appropriate size. > + */ > +int find_first_clear_extent_bit(struct extent_io_tree *tree, u64 start, > + u64 *start_ret, u64 *end_ret, unsigned bits) > +{ > + struct extent_state *state; > + struct rb_node *node, *prev = NULL, *next; > + int ret = 1; > + > + spin_lock(&tree->lock); > + > + /* Find first extent with bits cleared */ > + while (1) { > + node = __etree_search(tree, start, &next, &prev, NULL, NULL); > + if (!node) { > + node = next; > + if (!node) { > + /* > + * We are past the last allocated chunk, > + * set start at the end of the last extent. The > + * device alloc tree should never be empty so > + * prev is always set. > + */ > + ASSERT(prev); > + state = rb_entry(prev, struct extent_state, rb_node); > + *start_ret = state->end + 1; > + *end_ret = -1; > + ret = 0; > + goto out; Bummer this is not working as expected. For example, for a fs which doesn't have any holes it will return 0 but in fact it should return 1 and terminate the search. Have to figure how to distinguish between "everything after last extent until -1 is not allocated" VS "there is no extent which satisfies the condition so just return 1/failure" > + } > + } > + state = rb_entry(node, struct extent_state, rb_node); > + if (in_range(start, state->start, state->end - state->start + 1) && > + (state->state & bits)) { > + start = state->end + 1; > + } else { > + *start_ret = start; > + break; > + } > + } > + > + /* > + * Find the longest stretch from start until an entry which has the > + * bits set > + */ > + while (1) { > + state = rb_entry(node, struct extent_state, rb_node); > + if (state->end >= start && !(state->state & bits)) { > + *end_ret = state->end; > + ret = 0; > + } else { > + *end_ret = state->start - 1; > + ret = 0; > + break; > + } > + > + node = rb_next(node); > + if (!node) > + break; > + } > +out: > + spin_unlock(&tree->lock); > + return ret; > +} > + > /* > * find a contiguous range of bytes in the file marked as delalloc, not > * more than 'max_bytes'. start and end are used to return the range, > diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h > index d238efd628cf..7ddb3ec70023 100644 > --- a/fs/btrfs/extent_io.h > +++ b/fs/btrfs/extent_io.h > @@ -391,6 +391,8 @@ static inline int set_extent_uptodate(struct extent_io_tree *tree, u64 start, > int find_first_extent_bit(struct extent_io_tree *tree, u64 start, > u64 *start_ret, u64 *end_ret, unsigned bits, > struct extent_state **cached_state); > +int find_first_clear_extent_bit(struct extent_io_tree *tree, u64 start, > + u64 *start_ret, u64 *end_ret, unsigned bits); > int extent_invalidatepage(struct extent_io_tree *tree, > struct page *page, unsigned long offset); > int extent_write_full_page(struct page *page, struct writeback_control *wbc); >