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Tue, 23 Apr 2024 23:55:16 +0200 Message-ID: <79a004f4-952c-4382-ad75-e1b669df5ddc@gmx.com> Date: Wed, 24 Apr 2024 07:25:11 +0930 Precedence: bulk X-Mailing-List: linux-btrfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 01/15] btrfs: don't do find_extent_buffer in do_walk_down To: Josef Bacik , linux-btrfs@vger.kernel.org, kernel-team@fb.com References: Content-Language: en-US From: Qu Wenruo Autocrypt: addr=quwenruo.btrfs@gmx.com; keydata= xsBNBFnVga8BCACyhFP3ExcTIuB73jDIBA/vSoYcTyysFQzPvez64TUSCv1SgXEByR7fju3o 8RfaWuHCnkkea5luuTZMqfgTXrun2dqNVYDNOV6RIVrc4YuG20yhC1epnV55fJCThqij0MRL 1NxPKXIlEdHvN0Kov3CtWA+R1iNN0RCeVun7rmOrrjBK573aWC5sgP7YsBOLK79H3tmUtz6b 9Imuj0ZyEsa76Xg9PX9Hn2myKj1hfWGS+5og9Va4hrwQC8ipjXik6NKR5GDV+hOZkktU81G5 gkQtGB9jOAYRs86QG/b7PtIlbd3+pppT0gaS+wvwMs8cuNG+Pu6KO1oC4jgdseFLu7NpABEB AAHNIlF1IFdlbnJ1byA8cXV3ZW5ydW8uYnRyZnNAZ214LmNvbT7CwJQEEwEIAD4CGwMFCwkI BwIGFQgJCgsCBBYCAwECHgECF4AWIQQt33LlpaVbqJ2qQuHCPZHzoSX+qAUCY00iVQUJDToH pgAKCRDCPZHzoSX+qNKACACkjDLzCvcFuDlgqCiS4ajHAo6twGra3uGgY2klo3S4JespWifr BLPPak74oOShqNZ8yWzB1Bkz1u93Ifx3c3H0r2vLWrImoP5eQdymVqMWmDAq+sV1Koyt8gXQ XPD2jQCrfR9nUuV1F3Z4Lgo+6I5LjuXBVEayFdz/VYK63+YLEAlSowCF72Lkz06TmaI0XMyj jgRNGM2MRgfxbprCcsgUypaDfmhY2nrhIzPUICURfp9t/65+/PLlV4nYs+DtSwPyNjkPX72+ LdyIdY+BqS8cZbPG5spCyJIlZonADojLDYQq4QnufARU51zyVjzTXMg5gAttDZwTH+8LbNI4 mm2YzsBNBFnVga8BCACqU+th4Esy/c8BnvliFAjAfpzhI1wH76FD1MJPmAhA3DnX5JDORcga CbPEwhLj1xlwTgpeT+QfDmGJ5B5BlrrQFZVE1fChEjiJvyiSAO4yQPkrPVYTI7Xj34FnscPj /IrRUUka68MlHxPtFnAHr25VIuOS41lmYKYNwPNLRz9Ik6DmeTG3WJO2BQRNvXA0pXrJH1fN GSsRb+pKEKHKtL1803x71zQxCwLh+zLP1iXHVM5j8gX9zqupigQR/Cel2XPS44zWcDW8r7B0 q1eW4Jrv0x19p4P923voqn+joIAostyNTUjCeSrUdKth9jcdlam9X2DziA/DHDFfS5eq4fEv ABEBAAHCwHwEGAEIACYCGwwWIQQt33LlpaVbqJ2qQuHCPZHzoSX+qAUCY00ibgUJDToHvwAK CRDCPZHzoSX+qK6vB/9yyZlsS+ijtsvwYDjGA2WhVhN07Xa5SBBvGCAycyGGzSMkOJcOtUUf tD+ADyrLbLuVSfRN1ke738UojphwkSFj4t9scG5A+U8GgOZtrlYOsY2+cG3R5vjoXUgXMP37 INfWh0KbJodf0G48xouesn08cbfUdlphSMXujCA8y5TcNyRuNv2q5Nizl8sKhUZzh4BascoK DChBuznBsucCTAGrwPgG4/ul6HnWE8DipMKvkV9ob1xJS2W4WJRPp6QdVrBWJ9cCdtpR6GbL iQi22uZXoSPv/0oUrGU+U5X4IvdnvT+8viPzszL5wXswJZfqfy8tmHM85yjObVdIG6AlnrrD In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: quoted-printable X-Provags-ID: V03:K1:D3sE3alI+4LoQZDbkb5NG22bD1MrcpReRD+mxUHYyzJhsN51qp8 ZW0sZS0fJX4Bb6qrace1R3yCy0PgrNSdSkV6AP+Ta6LagHWWgZPW5iyi/f9TpJK7IltEIQn lHfUscK+xKBwS2OCpYwpJlBYJxx9YWxFwLuZXALbG2Il9nTJTG8mrfpHaJ4M7CbTu5b1eHJ 3U7+7Wx8nwUPxBDEheTAA== X-Spam-Flag: NO UI-OutboundReport: notjunk:1;M01:P0:Vapp+P1pdFI=;rCsvZ/gyyzUxcumuHCAj5JAlV3p 3nPo4qd7PvWQLZxMVYboF4IAfNH0zNI6F1+sxymPQBRO6VVJ7zJ+L8V6LA1K7yWKWUgzQc1HF 4LZvd/XJrjuc+thhUKCSGL0kmW4hUw9fPaS9zwDnISSVshaXnJWT9C+w/th9RLAgRCxZjR426 KFk4fjDQIlnkOlLCizxSOucVS44DjCQbpIojdlAmVNVGlETiWys1vUooX407ZQGFJTS7bIErE 4jMt9nM+mOQftK9rJ68N2L6si6O6aZRo+MAL3yAPOqTlBJe+K3TYEIznM9hVTu34p5TnDaOFO alsxJuICxqCHv/p4khnrRdjuN7EFtt0GVMEnvkI/CH0QBzhyNlTuizoawPg2Lut+TqWSOO5mX qFR0t+1lwtccbL9N4RzPSrm7ChHB+mVgQRc2TKYdqvNk0u6UV8ddP01gRRGTV4NbfQj/ujk8i KlylTN6P1QlmYP09K5XiA6znuPjfhGafYTHHh1UIAPEunIdFn0qsDZcSCdAdJpuE+Dpi3YXTE zM04wioWvNEjQAiNVEkJJrcIeZtywfY872Ya+wc2VuK7fLNYp+qqZlsjbOB20FY3Euv/mP4ep /oiP/6F4479P7+57vWpwQj9X2Onxx7IKeNNn2NrEKL7vKpj/x2XmBZWy39Jl5wQ+SHDUnX9Ry oxsWclxaDDm7zanYbaSqJ50NIzbJlq3px2fluDhkX+esBgWB58qXW93WFfhRiJYjxp0uqsUM6 UPrEEhx2qr9PjBQYKDdc1LkjbH7K4nhSDbQ2PctkY2UbSF17ya1w7uHClz9wYYFui9kpH2ACU JlanvvSoeTsZC3BsryY6Qkgz9fbOHFa3CXYO5xw+xQxLE= =E5=9C=A8 2024/4/20 03:46, Josef Bacik =E5=86=99=E9=81=93: > We do find_extent_buffer(), and then if we don't find the eb in cache we > call btrfs_find_create_tree_block(), which calls find_extent_buffer() > first and then allocates the extent buffer. > > The reason we're doing this is because if we don't find the extent > buffer in cache we set reada =3D 1. However this doesn't matter, becaus= e > lower down we only trigger reada if !btrfs_buffer_uptodate(eb), which is > what the case would be if we didn't find the extent buffer in cache and > had to allocate it. > > Clean this up to simply call btrfs_find_create_tree_block(), and then > use the fact that we're having to read the extent buffer off of disk to > go ahead and kick off readahead. > > Signed-off-by: Josef Bacik Reviewed-by: Qu Wenruo Thanks, Qu > --- > fs/btrfs/extent-tree.c | 16 ++++++---------- > 1 file changed, 6 insertions(+), 10 deletions(-) > > diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c > index 023920d0d971..64bb8c69e57a 100644 > --- a/fs/btrfs/extent-tree.c > +++ b/fs/btrfs/extent-tree.c > @@ -5434,7 +5434,6 @@ static noinline int do_walk_down(struct btrfs_tran= s_handle *trans, > struct btrfs_key key; > struct extent_buffer *next; > int level =3D wc->level; > - int reada =3D 0; > int ret =3D 0; > bool need_account =3D false; > > @@ -5460,14 +5459,11 @@ static noinline int do_walk_down(struct btrfs_tr= ans_handle *trans, > btrfs_node_key_to_cpu(path->nodes[level], &check.first_key, > path->slots[level]); > > - next =3D find_extent_buffer(fs_info, bytenr); > - if (!next) { > - next =3D btrfs_find_create_tree_block(fs_info, bytenr, > - btrfs_root_id(root), level - 1); > - if (IS_ERR(next)) > - return PTR_ERR(next); > - reada =3D 1; > - } > + next =3D btrfs_find_create_tree_block(fs_info, bytenr, > + btrfs_root_id(root), level - 1); > + if (IS_ERR(next)) > + return PTR_ERR(next); > + > btrfs_tree_lock(next); > > ret =3D btrfs_lookup_extent_info(trans, fs_info, bytenr, level - 1, 1= , > @@ -5518,7 +5514,7 @@ static noinline int do_walk_down(struct btrfs_tran= s_handle *trans, > } > > if (!next) { > - if (reada && level =3D=3D 1) > + if (level =3D=3D 1) > reada_walk_down(trans, root, wc, path); > next =3D read_tree_block(fs_info, bytenr, &check); > if (IS_ERR(next)) {