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Thu, 23 Jan 2020 03:54:24 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 26E78AD7B; Thu, 23 Jan 2020 08:54:21 +0000 (UTC) Subject: Re: [PATCH 11/11] btrfs: Use btrfs_transaction::pinned_extents To: Josef Bacik , linux-btrfs@vger.kernel.org References: <20200120140918.15647-1-nborisov@suse.com> <20200120140918.15647-12-nborisov@suse.com> From: Nikolay Borisov Autocrypt: addr=nborisov@suse.com; prefer-encrypt=mutual; keydata= xsFNBFiKBz4BEADNHZmqwhuN6EAzXj9SpPpH/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/ogKPk4ZxOXQEZetkEyTFghbRH2BIwARAQABzSJOaWtvbGF5IEJv cmlzb3YgPG5ib3Jpc292QHN1c2UuZGU+wsF4BBMBAgAiBQJYijkSAhsDBgsJCAcDAgYVCAIJ CgsEFgIDAQIeAQIXgAAKCRBxvoJG5T8oV/B6D/9a8EcRPdHg8uLEPywuJR8URwXzkofT5bZE IfGF0Z+Lt2ADe+nLOXrwKsamhweUFAvwEUxxnndovRLPOpWerTOAl47lxad08080jXnGfYFS Dc+ew7C3SFI4tFFHln8Y22Q9075saZ2yQS1ywJy+TFPADIprAZXnPbbbNbGtJLoq0LTiESnD w/SUC6sfikYwGRS94Dc9qO4nWyEvBK3Ql8NkoY0Sjky3B0vL572Gq0ytILDDGYuZVo4alUs8 LeXS5ukoZIw1QYXVstDJQnYjFxYgoQ5uGVi4t7FsFM/6ykYDzbIPNOx49Rbh9W4uKsLVhTzG BDTzdvX4ARl9La2kCQIjjWRg+XGuBM5rxT/NaTS78PXjhqWNYlGc5OhO0l8e5DIS2tXwYMDY LuHYNkkpMFksBslldvNttSNei7xr5VwjVqW4vASk2Aak5AleXZS+xIq2FADPS/XSgIaepyTV tkfnyreep1pk09cjfXY4A7qpEFwazCRZg9LLvYVc2M2eFQHDMtXsH59nOMstXx2OtNMcx5p8 0a5FHXE/HoXz3p9bD0uIUq6p04VYOHsMasHqHPbsMAq9V2OCytJQPWwe46bBjYZCOwG0+x58 fBFreP/NiJNeTQPOa6FoxLOLXMuVtpbcXIqKQDoEte9aMpoj9L24f60G4q+pL/54ql2VRscK d87BTQRYigc+ARAAyJSq9EFk28++SLfg791xOh28tLI6Yr8wwEOvM3wKeTfTZd+caVb9gBBy wxYhIopKlK1zq2YP7ZjTP1aPJGoWvcQZ8fVFdK/1nW+Z8/NTjaOx1mfrrtTGtFxVBdSCgqBB jHTnlDYV1R5plJqK+ggEP1a0mr/rpQ9dFGvgf/5jkVpRnH6BY0aYFPprRL8ZCcdv2DeeicOO YMobD5g7g/poQzHLLeT0+y1qiLIFefNABLN06Lf0GBZC5l8hCM3Rpb4ObyQ4B9PmL/KTn2FV Xq/c0scGMdXD2QeWLePC+yLMhf1fZby1vVJ59pXGq+o7XXfYA7xX0JsTUNxVPx/MgK8aLjYW hX+TRA4bCr4uYt/S3ThDRywSX6Hr1lyp4FJBwgyb8iv42it8KvoeOsHqVbuCIGRCXqGGiaeX Wa0M/oxN1vJjMSIEVzBAPi16tztL/wQtFHJtZAdCnuzFAz8ue6GzvsyBj97pzkBVacwp3/Mw qbiu7sDz7yB0d7J2tFBJYNpVt/Lce6nQhrvon0VqiWeMHxgtQ4k92Eja9u80JDaKnHDdjdwq FUikZirB28UiLPQV6PvCckgIiukmz/5ctAfKpyYRGfez+JbAGl6iCvHYt/wAZ7Oqe/3Cirs5 KhaXBcMmJR1qo8QH8eYZ+qhFE3bSPH446+5oEw8A9v5oonKV7zMAEQEAAcLBXwQYAQIACQUC WIoHPgIbDAAKCRBxvoJG5T8oV1pyD/4zdXdOL0lhkSIjJWGqz7Idvo0wjVHSSQCbOwZDWNTN JBTP0BUxHpPu/Z8gRNNP9/k6i63T4eL1xjy4umTwJaej1X15H8Hsh+zakADyWHadbjcUXCkg OJK4NsfqhMuaIYIHbToi9K5pAKnV953xTrK6oYVyd/Rmkmb+wgsbYQJ0Ur1Ficwhp6qU1CaJ mJwFjaWaVgUERoxcejL4ruds66LM9Z1Qqgoer62ZneID6ovmzpCWbi2sfbz98+kW46aA/w8r 7sulgs1KXWhBSv5aWqKU8C4twKjlV2XsztUUsyrjHFj91j31pnHRklBgXHTD/pSRsN0UvM26 lPs0g3ryVlG5wiZ9+JbI3sKMfbdfdOeLxtL25ujs443rw1s/PVghphoeadVAKMPINeRCgoJH zZV/2Z/myWPRWWl/79amy/9MfxffZqO9rfugRBORY0ywPHLDdo9Kmzoxoxp9w3uTrTLZaT9M KIuxEcV8wcVjr+Wr9zRl06waOCkgrQbTPp631hToxo+4rA1jiQF2M80HAet65ytBVR2pFGZF zGYYLqiG+mpUZ+FPjxk9kpkRYz61mTLSY7tuFljExfJWMGfgSg1OxfLV631jV1TcdUnx+h3l Sqs2vMhAVt14zT8mpIuu2VNxcontxgVr1kzYA/tQg32fVRbGr449j1gw57BV9i0vww== Message-ID: <3396ff95-dbc0-dd91-8c91-4509933e3a30@suse.com> Date: Thu, 23 Jan 2020 10:54:20 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.4.1 MIME-Version: 1.0 In-Reply-To: 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 22.01.20 г. 22:21 ч., Josef Bacik wrote: > On 1/20/20 9:09 AM, Nikolay Borisov wrote: >> This commit flips the switch to start tracking/processing pinned >> extents on a per-transaction basis. It mostly replaces all references >> from btrfs_fs_info::(pinned_extents|freed_extents[]) to >> btrfs_transaction::pinned_extents. Two notable modifications that >> warrant explicit mention are changing clean_pinned_extents to get a >> reference to the previously running transaction. The other one is >> removal of call to btrfs_destroy_pinned_extent since transactions are >> going to be cleaned in btrfs_cleanup_one_transaction. >> >> Signed-off-by: Nikolay Borisov > > I'd prefer if the excluded extent changes were separate from the pinned > extent changes. > >> --- >>   fs/btrfs/block-group.c       | 38 ++++++++++++++++++++++++------------ >>   fs/btrfs/ctree.h             |  4 ++-- >>   fs/btrfs/disk-io.c           | 30 +++++----------------------- >>   fs/btrfs/extent-io-tree.h    |  3 +-- >>   fs/btrfs/extent-tree.c       | 31 ++++++++--------------------- >>   fs/btrfs/free-space-cache.c  |  2 +- >>   fs/btrfs/tests/btrfs-tests.c |  7 ++----- >>   fs/btrfs/transaction.c       |  1 + >>   fs/btrfs/transaction.h       |  1 + >>   include/trace/events/btrfs.h |  3 +-- >>   10 files changed, 47 insertions(+), 73 deletions(-) >> >> diff --git a/fs/btrfs/block-group.c b/fs/btrfs/block-group.c >> index 48bb9e08f2e8..562dfb7dc77f 100644 >> --- a/fs/btrfs/block-group.c >> +++ b/fs/btrfs/block-group.c >> @@ -460,7 +460,7 @@ u64 add_new_free_space(struct btrfs_block_group >> *block_group, u64 start, u64 end >>       int ret; >>         while (start < end) { >> -        ret = find_first_extent_bit(info->pinned_extents, start, >> +        ret = find_first_extent_bit(&info->excluded_extents, start, >>                           &extent_start, &extent_end, >>                           EXTENT_DIRTY | EXTENT_UPTODATE, >>                           NULL); > > We're no longer doing EXTENT_DIRTY in excluded_extents, so we don't need > this part. > >> @@ -1233,32 +1233,44 @@ static int inc_block_group_ro(struct >> btrfs_block_group *cache, int force) >>       return ret; >>   } >>   -static bool clean_pinned_extents(struct btrfs_block_group *bg) >> +static bool clean_pinned_extents(struct btrfs_trans_handle *trans, >> +                 struct btrfs_block_group *bg) >>   { >>       struct btrfs_fs_info *fs_info = bg->fs_info; >> +    struct btrfs_transaction *prev_trans = NULL; >>       u64 start = bg->start; >>       u64 end = start + bg->length - 1; >>       int ret; >>   +    spin_lock(&fs_info->trans_lock); >> +    if (trans->transaction->list.prev != &fs_info->trans_list) { >> +        prev_trans = list_entry(trans->transaction->list.prev, >> +                    struct btrfs_transaction, list); >> +        refcount_inc(&prev_trans->use_count); >> +    } >> +    spin_unlock(&fs_info->trans_lock); >> + >>       /* >>        * Hold the unused_bg_unpin_mutex lock to avoid racing with >>        * btrfs_finish_extent_commit(). If we are at transaction N, >>        * another task might be running finish_extent_commit() for the >>        * previous transaction N - 1, and have seen a range belonging >> -     * to the block group in freed_extents[] before we were able to >> -     * clear the whole block group range from freed_extents[]. This >> +     * to the block group in pinned_extents before we were able to >> +     * clear the whole block group range from pinned_extents. This >>        * means that task can lookup for the block group after we >> -     * unpinned it from freed_extents[] and removed it, leading to >> +     * unpinned it from pinned_extents[] and removed it, leading to >>        * a BUG_ON() at unpin_extent_range(). >>        */ >>       mutex_lock(&fs_info->unused_bg_unpin_mutex); >> -    ret = clear_extent_bits(&fs_info->freed_extents[0], start, end, >> -              EXTENT_DIRTY); >> -    if (ret) >> -        goto failure; >> +    if (prev_trans) { >> +        ret = clear_extent_bits(&prev_trans->pinned_extents, start, end, >> +                    EXTENT_DIRTY); >> +        if (ret) >> +            goto failure; >> +    } > > You are leaking a ref to prev_trans here. > > >> diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c >> index 9209c7b0997c..3cb786463eb2 100644 >> --- a/fs/btrfs/disk-io.c >> +++ b/fs/btrfs/disk-io.c >> @@ -2021,10 +2021,8 @@ void btrfs_free_fs_roots(struct btrfs_fs_info >> *fs_info) >>               btrfs_drop_and_free_fs_root(fs_info, gang[i]); >>       } >>   -    if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) { >> +    if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) >>           btrfs_free_log_root_tree(NULL, fs_info); >> -        btrfs_destroy_pinned_extent(fs_info, fs_info->pinned_extents); >> -    } > > What about the excluded extents?  We may never cache the block group > with one of the super mirrors in it, and thus we would leak the excluded > extent for it.  Thanks, btrfs_destroy_pinned_extent didn't touch EXTENT_UPDATE (excluded extents) before so my removing this call doesn't change that. E.g. if there is a bug here where excluded extents are not cleaned up then it's not due to my code. On the other hand I don't quite understand your concern w.r.t pinned extents. Can you elaborate? > > Josef