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Fri, 31 Jan 2020 20:00:24 -0500 Received: from mout.gmx.net ([212.227.15.18]:46421 "EHLO mout.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726264AbgBABAY (ORCPT ); Fri, 31 Jan 2020 20:00:24 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gmx.net; s=badeba3b8450; t=1580518813; bh=X5yqz1eLiL2/C2guD8krJly0VZMEVx4u7OZcA6Erdk4=; h=X-UI-Sender-Class:Subject:To:Cc:References:From:Date:In-Reply-To; b=cn35FR315hMBNdlw1Z7uARCJo53rZiGLiIRooH9xKF/4Ri6Op/F63OS9kn02hLOgZ hNB20da7wSsg2yrmM4zhbYTNRtgOQsD9zzfrscM037W9kWAHaHOnB/+rfBlursdVdJ tpkMrMTrMz9tfi7aFUd0L07VgCt7bmmxBXxBz71o= X-UI-Sender-Class: 01bb95c1-4bf8-414a-932a-4f6e2808ef9c Received: from [0.0.0.0] ([149.28.201.231]) by mail.gmx.com (mrgmx004 [212.227.17.184]) with ESMTPSA (Nemesis) id 1MXGrE-1j3iVO48dC-00YlvU; Sat, 01 Feb 2020 02:00:13 +0100 Subject: Re: [PATCH] btrfs: do not zero f_bavail if we have available space To: Josef Bacik , linux-btrfs@vger.kernel.org, kernel-team@fb.com Cc: Martin Steigerwald References: <20200131143105.52092-1-josef@toxicpanda.com> From: Qu Wenruo Autocrypt: addr=quwenruo.btrfs@gmx.com; prefer-encrypt=mutual; keydata= mQENBFnVga8BCACyhFP3ExcTIuB73jDIBA/vSoYcTyysFQzPvez64TUSCv1SgXEByR7fju3o 8RfaWuHCnkkea5luuTZMqfgTXrun2dqNVYDNOV6RIVrc4YuG20yhC1epnV55fJCThqij0MRL 1NxPKXIlEdHvN0Kov3CtWA+R1iNN0RCeVun7rmOrrjBK573aWC5sgP7YsBOLK79H3tmUtz6b 9Imuj0ZyEsa76Xg9PX9Hn2myKj1hfWGS+5og9Va4hrwQC8ipjXik6NKR5GDV+hOZkktU81G5 gkQtGB9jOAYRs86QG/b7PtIlbd3+pppT0gaS+wvwMs8cuNG+Pu6KO1oC4jgdseFLu7NpABEB AAG0IlF1IFdlbnJ1byA8cXV3ZW5ydW8uYnRyZnNAZ214LmNvbT6JAU4EEwEIADgCGwMFCwkI BwIGFQgJCgsCBBYCAwECHgECF4AWIQQt33LlpaVbqJ2qQuHCPZHzoSX+qAUCXZw1oQAKCRDC PZHzoSX+qCY6CACd+mWu3okGwRKXju6bou+7VkqCaHTdyXwWFTsr+/0ly5nUdDtT3yEVggPJ 3VP70wjlrxUjNjFb6iIvGYxiPOrop1NGwGYvQktgRhaIhALG6rPoSSAhGNjwGVRw0km0PlIN D29BTj/lYEk+jVM1YL0QLgAE1AI3krihg/lp/fQT53wLhR8YZIF8ETXbClQG1vJ0cllPuEEv efKxRyiTSjB+PsozSvYWhXsPeJ+KKjFen7ebE5reQTPFzSHctCdPnoR/4jSPlnTlnEvLeqcD ZTuKfQe1gWrPeevQzgCtgBF/WjIOeJs41klnYzC3DymuQlmFubss0jShLOW8eSOOWhLRuQEN BFnVga8BCACqU+th4Esy/c8BnvliFAjAfpzhI1wH76FD1MJPmAhA3DnX5JDORcgaCbPEwhLj 1xlwTgpeT+QfDmGJ5B5BlrrQFZVE1fChEjiJvyiSAO4yQPkrPVYTI7Xj34FnscPj/IrRUUka 68MlHxPtFnAHr25VIuOS41lmYKYNwPNLRz9Ik6DmeTG3WJO2BQRNvXA0pXrJH1fNGSsRb+pK EKHKtL1803x71zQxCwLh+zLP1iXHVM5j8gX9zqupigQR/Cel2XPS44zWcDW8r7B0q1eW4Jrv 0x19p4P923voqn+joIAostyNTUjCeSrUdKth9jcdlam9X2DziA/DHDFfS5eq4fEvABEBAAGJ ATwEGAEIACYCGwwWIQQt33LlpaVbqJ2qQuHCPZHzoSX+qAUCXZw1rgUJCWpOfwAKCRDCPZHz oSX+qFcEB/95cs8cM1OQdE/GgOfCGxwgckMeWyzOR7bkAWW0lDVp2hpgJuxBW/gyfmtBnUai fnggx3EE3ev8HTysZU9q0h+TJwwJKGv6sUc8qcTGFDtavnnl+r6xDUY7A6GvXEsSoCEEynby 72byGeSovfq/4AWGNPBG1L61Exl+gbqfvbECP3ziXnob009+z9I4qXodHSYINfAkZkA523JG ap12LndJeLk3gfWNZfXEWyGnuciRGbqESkhIRav8ootsCIops/SqXm0/k+Kcl4gGUO/iD/T5 oagaDh0QtOd8RWSMwLxwn8uIhpH84Q4X1LadJ5NCgGa6xPP5qqRuiC+9gZqbq4Nj Message-ID: Date: Sat, 1 Feb 2020 09:00:09 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.4.2 MIME-Version: 1.0 In-Reply-To: <20200131143105.52092-1-josef@toxicpanda.com> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="MvnEwlhih987ruTs1o41Gl7K5XGeDl0QX" X-Provags-ID: V03:K1:DRCCDAhOI0jtHG8D6GcCjUOoEuzlxes+r+tCod/Z8pr8V9eY3wQ S0MYD/X/yp7dpzTTVFP0NkH8f88gtDT6Bc9qD2G1FoKiwvLh8l97/gpH+wQl/NC5HVGN9mp evtgCDkvxnFpX6b1SaOf6ACZqkLGbsKcW9cqP9repjzG6Lpj4/425acjkvh+Y55HhXvFn/v s6vm9sPZnNpRDjKbzLEfg== X-UI-Out-Filterresults: notjunk:1;V03:K0:eAPwBpkzC+8=:whZhPttkJ1hh4e5my+scv9 ZL5U5rp1YZvC45wor34wZDL/VV4+EeGealkrPGjldQVagVMRqWiDwYv1hgnKme33wZZc5AzL7 vsPVDTPa4rnMqcw8JUtWTo9u0bCOsY/QoEkmhiL6gBmaTzHWZGJ9dOTrql+yjm1xo/GcVrUY7 9minXkui1wIW4XU4RbB3tgxOrB64r6rgG4rzHYiesMzY1NbmYSp/GvRFjfFw2COR7k2pgniSP f0wytoBBRE354OvKeywnaxn+3NyOp8gn3tOB0GFQxyzfS8TatrCOg1yts6GMdkezsSIt1Ntxo 1E7IcIspybC/61C9yhAeHq6zu/7Y+1H1kJwZ2vFsTyqm9T6KQV0xTH0X1scUcO1NGaiTBXKIi CAol/glR38ZHtke0oj0YzAkBL1Deg75h8DvTxntftvdsWnR4WevkBvIr6P17rTou/u/126Ex3 6GM4teo6vDIMIp1DTbcdN+ChwHPSlHp/Orm1eWZ1nFWa1hf938mYE00cCCuEisXnDIvxpvCcD AUl0UR0ouduHM9wYNfSMsT87KyoNtc5Ps7bK7oth7oMnhEwnOIWQoGTra0JIKjazg5W591pX+ iJMXQB49z7VBSitXWeMBqeI2WDWQ8+TuucA5ThleOb4K6qHXv8eILBwnyxxtEws+RoyxKpWZj L7tSdCl/ZmYY7PcDshK045KEVFouf9Y2J15Ekjclew8CjAaN7pL6pxD/T34nINB4fS0HdDWQj diwi5DsgrcRfPwH1XwkibdgtBNEbKlimAre6nbeUvOzac0v/EMn0AOU5ZxtQjNuJ9861+uMgb AkVmKrCEcMrSHNviiPIZ6sZefCKZcIjNJkYpNttBA1qx+1MVDf9dmvtFPcZVCVqdd0gKPTVeb UnT6mYiHwECH13aaG54YtqdeZ0e/+RyrPR2J2lNp/5FO4AQLi5xmHQP17kL06y8YrDdKWZjnC k8A7ekij9FRqsS7gnfp9kqUIdCGOMzRzjKkxMej07u9p6Biw61b3hIdhlm/ndd1O/I1lGaqkI SRBEgtYx2jv1VxY2BrmfrV8Djvg+L4i3Ze4LNGwXRxyuXRM61BcUvFgbJ7z7bUVPoJ3A43K27 TupYbaCtO9NFDYpnQFJz9G70k7h5KXzi41RAoHiM8D6mIWnex7KG7hdQ5N5a6lWodWzaCLhld bjOS8fNoQoE881dBPLih57PivKlmcoZy3Zrt32nxQ2+dFd8JGKDsnahCJMEcjrQ12zEogzj+h RXH6+mUtRF9xQMDxV Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --MvnEwlhih987ruTs1o41Gl7K5XGeDl0QX Content-Type: multipart/mixed; boundary="I0xz7wpoYuIF72rt4fTwx67hdkt8Efl1C" --I0xz7wpoYuIF72rt4fTwx67hdkt8Efl1C Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable On 2020/1/31 =E4=B8=8B=E5=8D=8810:31, Josef Bacik wrote: > There was some logic added a while ago to clear out f_bavail in statfs(= ) > if we did not have enough free metadata space to satisfy our global > reserve. This was incorrect at the time, however didn't really pose a > problem for normal file systems because we would often allocate chunks > if we got this low on free metadata space, and thus wouldn't really hit= > this case unless we were actually full. >=20 > Fast forward to today and now we are much better about not allocating > metadata chunks all of the time. Couple this with d792b0f19711 which > now means we'll easily have a larger global reserve than our free space= , > we are now more likely to trip over this while still having plenty of > space. >=20 > Fix this by skipping this logic if the global rsv's space_info is not > full. space_info->full is 0 unless we've attempted to allocate a chunk= > for that space_info and that has failed. If this happens then the spac= e > for the global reserve is definitely sacred and we need to report > b_avail =3D=3D 0, but before then we can just use our calculated b_avai= l. >=20 > There are other cases where df isn't quite right, and Qu is addressing > them in a more holistic way. This simply fixes the users that are > currently experiencing pain because of this problem. >=20 > Fixes: ca8a51b3a979 ("btrfs: statfs: report zero available if metadata = are exhausted") > Reported-by: Martin Steigerwald > Signed-off-by: Josef Bacik Reviewed-by: Qu Wenruo Thanks, Qu > --- > fs/btrfs/super.c | 10 +++++++++- > 1 file changed, 9 insertions(+), 1 deletion(-) >=20 > diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c > index d421884f0c23..42433ca822aa 100644 > --- a/fs/btrfs/super.c > +++ b/fs/btrfs/super.c > @@ -2143,7 +2143,15 @@ static int btrfs_statfs(struct dentry *dentry, s= truct kstatfs *buf) > */ > thresh =3D SZ_4M; > =20 > - if (!mixed && total_free_meta - thresh < block_rsv->size) > + /* > + * We only want to claim there's no available space if we can no long= er > + * allocate chunks for our metadata profile and our global reserve wi= ll > + * not fit in the free metadata space. If we aren't ->full then we > + * still can allocate chunks and thus are fine using the currently > + * calculated f_bavail. > + */ > + if (!mixed && block_rsv->space_info->full && > + total_free_meta - thresh < block_rsv->size) > buf->f_bavail =3D 0; > =20 > buf->f_type =3D BTRFS_SUPER_MAGIC; >=20 --I0xz7wpoYuIF72rt4fTwx67hdkt8Efl1C-- --MvnEwlhih987ruTs1o41Gl7K5XGeDl0QX Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEELd9y5aWlW6idqkLhwj2R86El/qgFAl40zZkACgkQwj2R86El /qhLngf+KwUT3TlWUYDooidyH7KV3h7xxFw47GDZQcNYnqtnj92APL7E2Ln70APo fLTxTEnPjKPRolWcbtJDhz5udEbklAlZSom+ZQ45KZ0AP2JoMlo61EQXzykfMJVZ gZdPgQWoMubQ1PppX72m96RV+mKxhCImcMuOrFL9TIWWypJxX5NFAuhdmC0rFbZh otEj5D7ftB6ur4ZcyyM9duXNzL4WLBA0eeT8DK348NeTUeUpfQ+TW8q7cxT0qdbl 59/0K1cTSnXkpqGxpw3Nfbjk75CHrC13ziqRXnY7UmN3MFwTzUbdDKCJjMBizAll RlcONPPfVFbMZjzTlHWivvwWlakQLw== =11k0 -----END PGP SIGNATURE----- --MvnEwlhih987ruTs1o41Gl7K5XGeDl0QX--