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Sat, 18 May 2024 00:51:40 +0200 Message-ID: Date: Sat, 18 May 2024 08:21:36 +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 2/3] btrfs: use READ_ONCE() when accessing delayed_node at btrfs_dirty_node() To: fdmanana@kernel.org, linux-btrfs@vger.kernel.org References: <68f8da7780333faba472e44689f977abd7222ffc.1715951291.git.fdmanana@suse.com> 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: <68f8da7780333faba472e44689f977abd7222ffc.1715951291.git.fdmanana@suse.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: quoted-printable X-Provags-ID: V03:K1:w9teGsgpzSp6ZkFIhECN+EJNBTvhEjDiUdI21UHSygaBHALtfCu ld93Ef8Uphbw7hStmg0jnp534Cdiy1T5mIgfEDSFEKPd/KKUd8BFjwL90FsbEa7L9NM+g/Z y3Nzk92x7UvS0qbIiEdRYmoziwSwPtapb8Ji2DtDOXoGqjR+AMADgyBQjkIG9QrenFEdDU7 oH6jdy30vOnmH0LeiIybA== X-Spam-Flag: NO UI-OutboundReport: notjunk:1;M01:P0:HjWcJCTpNOI=;g38DGURTQHx0peILdddzsVbrCSx m7cUebWPZfaXBqMcYIAqv1AznzEMrOtS00QoEbJs05jGpB3kEGlGijVAoA0GKER6SgneGAa8b 6bYuBGbWnMlYpYtH00Mbi0zLs4ZPlrbThtI7HMuBgdg80Khr0X9+K7ib948y5kfooekfg5Tev ohiNtGNjTYXRZ1jc4eqLHGG6s5QTGdA4CjvHLkDsynP2Fk8X/WK6Ph5h92guIzIq4NHs0B3tG 43R1O2HiTBFmN8njPc+ULCRGO9wS5Tv4qfbclhTLkkqsHLS/S8+KfaoD5OwWJhTawK/TbQqid UCg+hvqtKJEQzmqSuwERN+238tzMJ+QH9e2JHqK67wAmn0VnQAw6h3mGIOzgvx95t7DJE55t3 eerrdWznSuxMxNmhuMMav/vSOfmgXL9NuIOLmf/ja+fyzVqegMylVIFm/vBcGOGps7U1RzWQe wJG9xLoQbUpWvdPFzkEv6OasLCf9aeHWXMgVX+wcFkMA7/DJxeDQR9L5dmS6gnJqD3AbzindJ Zh8gLEYkZj1igq9vGHyHupajfsJBzSmrRe31vfDDTrka6Fj9lTF4gtmzT6tSHISgE987NYVj8 5GzdzMiHjA5GV4WUP58awo6HKqaiktFTlEZKV3x9KEi/YyMSZiYSYqzzPzl9Tt7oNCrjeUBxE CZ38ZyBMwpxtVv8WZkMiL78G7E/QyjRmOgCJn17JodkGONfRfTmbGG+XkEweaJfZyGDlRBMEC smsuzYu2QW/EdZjj/BpldwLd7SY1+OynAHBe6KRHSynmV1yHlUQN5KHeuXUovs884wy/Q62mX srD/sktNZFIuSxqm029xlCdodzhDh+tUsAXAd888pqJpY= =E5=9C=A8 2024/5/17 22:43, fdmanana@kernel.org =E5=86=99=E9=81=93: > From: Filipe Manana > > An inode's delayed_node is set while holding the root->delayed_nodes > xarray's lock, so accessing it without holding the lock at > btrfs_dirty_node() is racy and will likely trigger warnings from tools > like KCSAN. > > Since we update the inode's delayed_node with WRITE_ONCE(), we can use > READ_ONCE() without taking the lock, as we do in several other places > at delayed-inode.c. So change btrfs_dirty_node() to use READ_ONCE(). > > Signed-off-by: Filipe Manana Reviewed-by: Qu Wenruo Thanks, Qu > --- > fs/btrfs/inode.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c > index 000809e16aba..11cad22d7b4c 100644 > --- a/fs/btrfs/inode.c > +++ b/fs/btrfs/inode.c > @@ -6100,7 +6100,7 @@ static int btrfs_dirty_inode(struct btrfs_inode *i= node) > ret =3D btrfs_update_inode(trans, inode); > } > btrfs_end_transaction(trans); > - if (inode->delayed_node) > + if (READ_ONCE(inode->delayed_node)) > btrfs_balance_delayed_items(fs_info); > > return ret;