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[46.135.21.74]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-46e23adce1bsm9710525e9.24.2025.09.23.03.47.22 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 23 Sep 2025 03:47:23 -0700 (PDT) From: Mateusz Guzik To: brauner@kernel.org Cc: viro@zeniv.linux.org.uk, jack@suse.cz, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, josef@toxicpanda.com, kernel-team@fb.com, amir73il@gmail.com, linux-btrfs@vger.kernel.org, linux-ext4@vger.kernel.org, linux-xfs@vger.kernel.org, ceph-devel@vger.kernel.org, linux-unionfs@vger.kernel.org, Mateusz Guzik Subject: [PATCH v6 1/4] fs: provide accessors for ->i_state Date: Tue, 23 Sep 2025 12:47:07 +0200 Message-ID: <20250923104710.2973493-2-mjguzik@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20250923104710.2973493-1-mjguzik@gmail.com> References: <20250923104710.2973493-1-mjguzik@gmail.com> Precedence: bulk X-Mailing-List: linux-unionfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Open-coded accesses prevent asserting they are done correctly. One obvious aspect is locking, but significantly more can checked. For example it can be detected when the code is clearing flags which are already missing, or is setting flags when it is illegal (e.g., I_FREEING when ->i_count > 0). Given the late stage of the release cycle this patchset only aims to hide access, it does not provide any of the checks. Consumers can be trivially converted. Suppose flags I_A and I_B are to be handled, then: state = inode->i_state => state = inode_state_read(inode) inode->i_state |= (I_A | I_B) => inode_state_set(inode, I_A | I_B) inode->i_state &= ~(I_A | I_B) => inode_state_clear(inode, I_A | I_B) inode->i_state = I_A | I_B => inode_state_assign(inode, I_A | I_B) Note open-coded access compiles just fine until the last patch in the series. Signed-off-by: Mateusz Guzik --- include/linux/fs.h | 33 +++++++++++++++++++++++++++++++-- 1 file changed, 31 insertions(+), 2 deletions(-) diff --git a/include/linux/fs.h b/include/linux/fs.h index c4fd010cf5bf..06bece8d1f18 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -756,7 +756,7 @@ enum inode_state_bits { /* reserved wait address bit 3 */ }; -enum inode_state_flags_t { +enum inode_state_flags_enum { I_NEW = (1U << __I_NEW), I_SYNC = (1U << __I_SYNC), I_LRU_ISOLATING = (1U << __I_LRU_ISOLATING), @@ -840,7 +840,7 @@ struct inode { #endif /* Misc */ - enum inode_state_flags_t i_state; + enum inode_state_flags_enum i_state; /* 32-bit hole */ struct rw_semaphore i_rwsem; @@ -899,6 +899,35 @@ struct inode { void *i_private; /* fs or device private pointer */ } __randomize_layout; +/* + * i_state handling + * + * We hide all of it behind helpers so that we can validate consumers. + */ +static inline enum inode_state_flags_enum inode_state_read(struct inode *inode) +{ + return READ_ONCE(inode->i_state); +} + +static inline void inode_state_set(struct inode *inode, + enum inode_state_flags_enum flags) +{ + WRITE_ONCE(inode->i_state, inode->i_state | flags); +} + +static inline void inode_state_clear(struct inode *inode, + enum inode_state_flags_enum flags) +{ + WRITE_ONCE(inode->i_state, inode->i_state & ~flags); + +} + +static inline void inode_state_assign(struct inode *inode, + enum inode_state_flags_enum flags) +{ + WRITE_ONCE(inode->i_state, flags); +} + static inline void inode_set_cached_link(struct inode *inode, char *link, int linklen) { VFS_WARN_ON_INODE(strlen(link) != linklen, inode); -- 2.43.0