From: Jeff Layton Subject: [RFC PATCH v1 11/30] fs: new API for handling i_version Date: Wed, 21 Dec 2016 12:03:28 -0500 Message-ID: <1482339827-7882-12-git-send-email-jlayton@redhat.com> References: <1482339827-7882-1-git-send-email-jlayton@redhat.com> Cc: linux-kernel@vger.kernel.org, linux-nfs@vger.kernel.org, linux-ext4@vger.kernel.org, linux-btrfs@vger.kernel.org, linux-xfs@vger.kernel.org To: linux-fsdevel@vger.kernel.org Return-path: In-Reply-To: <1482339827-7882-1-git-send-email-jlayton@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org We already have inode_inc_iversion. Add inode_set_iversion, inode_get_iversion, inode_cmp_iversion and inode_iversion_need_inc. These should encompass how i_version is currently accessed and manipulated so that we can later change the implementation. Signed-off-by: Jeff Layton --- include/linux/fs.h | 109 ++++++++++++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 104 insertions(+), 5 deletions(-) diff --git a/include/linux/fs.h b/include/linux/fs.h index 2ba074328894..075c915fe2b1 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1962,18 +1962,117 @@ static inline void inode_dec_link_count(struct inode *inode) } /** + * inode_set_iversion - set i_version to a particular value + * @inode: inode to set + * @new: new i_version value to set + * + * Set the inode's i_version. Should generally be called when initializing + * a new inode. + */ +static inline void +inode_set_iversion(struct inode *inode, const u64 new) +{ + inode->i_version = new; +} + +/** + * inode_inc_iversion_locked - increment i_version while protected + * @inode: inode to be updated + * + * Increment the i_version field in the inode. This version is usable + * when there is some other sort of lock in play that would prevent + * concurrent accessors. + */ +static inline void +inode_inc_iversion_locked(struct inode *inode) +{ + inode->i_version++; +} + +/** + * inode_set_iversion_read - set i_version to a particular value and flag + * set flag to indicate that it has been viewed + * @inode: inode to set + * @new: new i_version value to set + * + * Set the inode's i_version, and flag the inode as if it has been viewed. + * Should generally be called when initializinga new inode in memory from + * from disk. + */ +static inline void +inode_set_iversion_read(struct inode *inode, const u64 new) +{ + inode_set_iversion(inode, new); +} + +/** * inode_inc_iversion - increments i_version * @inode: inode that need to be updated * * Every time the inode is modified, the i_version field will be incremented. - * The filesystem has to be mounted with i_version flag + * The filesystem has to be mounted with MS_I_VERSION flag. + */ +static inline bool +inode_inc_iversion(struct inode *inode) +{ + spin_lock(&inode->i_lock); + inode_inc_iversion_locked(inode); + spin_unlock(&inode->i_lock); + return true; +} + +/** + * inode_get_iversion_raw - read i_version without "perturbing" it + * @inode: inode from which i_version should be read + * + * Read the inode i_version counter for an inode without registering it as a + * read. Should typically be used by local filesystems that need to store an + * i_version on disk. + */ +static inline u64 +inode_get_iversion_raw(const struct inode *inode) +{ + return inode->i_version; +} + +/** + * inode_get_iversion - read i_version for later use + * @inode: inode from which i_version should be read + * + * Read the inode i_version counter. This should be used by callers that wish + * to store the returned i_version for later comparison. + */ +static inline u64 +inode_get_iversion(const struct inode *inode) +{ + return inode_get_iversion_raw(inode); +} + +/** + * inode_cmp_iversion - check whether the i_version counter has changed + * @inode: inode to check + * @old: old value to check against its i_version + * + * Compare an i_version counter with a previous one. Returns 0 if they are + * the same or non-zero if they are different. */ +static inline s64 +inode_cmp_iversion(const struct inode *inode, const u64 old) +{ + return (s64)inode->i_version - (s64)old; +} -static inline void inode_inc_iversion(struct inode *inode) +/** + * inode_iversion_need_inc - is the i_version in need of being incremented? + * @inode: inode to check + * + * Returns whether the inode->i_version counter needs incrementing on the next + * change. + */ +static inline bool +inode_iversion_need_inc(struct inode *inode) { - spin_lock(&inode->i_lock); - inode->i_version++; - spin_unlock(&inode->i_lock); + return true; } enum file_time_flags { -- 2.7.4