| Message ID | 20230124193025.185781-2-jlayton@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | fs: clean up internal i_version handling | expand |
On Tue 24-01-23 14:30:18, Jeff Layton wrote: > Reviewed-by: NeilBrown <neilb@suse.de> > Signed-off-by: Jeff Layton <jlayton@kernel.org> Reasonable. Feel free to add: Reviewed-by: Jan Kara <jack@suse.cz> Honza > --- > fs/libfs.c | 36 ++++++++++++++++++++++++++++++++++++ > include/linux/iversion.h | 38 ++------------------------------------ > 2 files changed, 38 insertions(+), 36 deletions(-) > > diff --git a/fs/libfs.c b/fs/libfs.c > index aada4e7c8713..17ecc47696e1 100644 > --- a/fs/libfs.c > +++ b/fs/libfs.c > @@ -1582,3 +1582,39 @@ bool inode_maybe_inc_iversion(struct inode *inode, bool force) > return true; > } > EXPORT_SYMBOL(inode_maybe_inc_iversion); > + > +/** > + * inode_query_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. This will guarantee > + * that a later query of the i_version will result in a different value if > + * anything has changed. > + * > + * In this implementation, we fetch the current value, set the QUERIED flag and > + * then try to swap it into place with a cmpxchg, if it wasn't already set. If > + * that fails, we try again with the newly fetched value from the cmpxchg. > + */ > +u64 inode_query_iversion(struct inode *inode) > +{ > + u64 cur, new; > + > + cur = inode_peek_iversion_raw(inode); > + do { > + /* If flag is already set, then no need to swap */ > + if (cur & I_VERSION_QUERIED) { > + /* > + * This barrier (and the implicit barrier in the > + * cmpxchg below) pairs with the barrier in > + * inode_maybe_inc_iversion(). > + */ > + smp_mb(); > + break; > + } > + > + new = cur | I_VERSION_QUERIED; > + } while (!atomic64_try_cmpxchg(&inode->i_version, &cur, new)); > + return cur >> I_VERSION_QUERIED_SHIFT; > +} > +EXPORT_SYMBOL(inode_query_iversion); > diff --git a/include/linux/iversion.h b/include/linux/iversion.h > index e27bd4f55d84..6755d8b4f20b 100644 > --- a/include/linux/iversion.h > +++ b/include/linux/iversion.h > @@ -234,42 +234,6 @@ inode_peek_iversion(const struct inode *inode) > return inode_peek_iversion_raw(inode) >> I_VERSION_QUERIED_SHIFT; > } > > -/** > - * inode_query_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. This will guarantee > - * that a later query of the i_version will result in a different value if > - * anything has changed. > - * > - * In this implementation, we fetch the current value, set the QUERIED flag and > - * then try to swap it into place with a cmpxchg, if it wasn't already set. If > - * that fails, we try again with the newly fetched value from the cmpxchg. > - */ > -static inline u64 > -inode_query_iversion(struct inode *inode) > -{ > - u64 cur, new; > - > - cur = inode_peek_iversion_raw(inode); > - do { > - /* If flag is already set, then no need to swap */ > - if (cur & I_VERSION_QUERIED) { > - /* > - * This barrier (and the implicit barrier in the > - * cmpxchg below) pairs with the barrier in > - * inode_maybe_inc_iversion(). > - */ > - smp_mb(); > - break; > - } > - > - new = cur | I_VERSION_QUERIED; > - } while (!atomic64_try_cmpxchg(&inode->i_version, &cur, new)); > - return cur >> I_VERSION_QUERIED_SHIFT; > -} > - > /* > * For filesystems without any sort of change attribute, the best we can > * do is fake one up from the ctime: > @@ -283,6 +247,8 @@ static inline u64 time_to_chattr(struct timespec64 *t) > return chattr; > } > > +u64 inode_query_iversion(struct inode *inode); > + > /** > * inode_eq_iversion_raw - check whether the raw i_version counter has changed > * @inode: inode to check > -- > 2.39.1 >
On Tue, Jan 24, 2023 at 02:30:18PM -0500, Jeff Layton wrote: > Reviewed-by: NeilBrown <neilb@suse.de> > Signed-off-by: Jeff Layton <jlayton@kernel.org> > --- Looks good to me, Reviewed-by: Christian Brauner <brauner@kernel.org>
diff --git a/fs/libfs.c b/fs/libfs.c index aada4e7c8713..17ecc47696e1 100644 --- a/fs/libfs.c +++ b/fs/libfs.c @@ -1582,3 +1582,39 @@ bool inode_maybe_inc_iversion(struct inode *inode, bool force) return true; } EXPORT_SYMBOL(inode_maybe_inc_iversion); + +/** + * inode_query_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. This will guarantee + * that a later query of the i_version will result in a different value if + * anything has changed. + * + * In this implementation, we fetch the current value, set the QUERIED flag and + * then try to swap it into place with a cmpxchg, if it wasn't already set. If + * that fails, we try again with the newly fetched value from the cmpxchg. + */ +u64 inode_query_iversion(struct inode *inode) +{ + u64 cur, new; + + cur = inode_peek_iversion_raw(inode); + do { + /* If flag is already set, then no need to swap */ + if (cur & I_VERSION_QUERIED) { + /* + * This barrier (and the implicit barrier in the + * cmpxchg below) pairs with the barrier in + * inode_maybe_inc_iversion(). + */ + smp_mb(); + break; + } + + new = cur | I_VERSION_QUERIED; + } while (!atomic64_try_cmpxchg(&inode->i_version, &cur, new)); + return cur >> I_VERSION_QUERIED_SHIFT; +} +EXPORT_SYMBOL(inode_query_iversion); diff --git a/include/linux/iversion.h b/include/linux/iversion.h index e27bd4f55d84..6755d8b4f20b 100644 --- a/include/linux/iversion.h +++ b/include/linux/iversion.h @@ -234,42 +234,6 @@ inode_peek_iversion(const struct inode *inode) return inode_peek_iversion_raw(inode) >> I_VERSION_QUERIED_SHIFT; } -/** - * inode_query_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. This will guarantee - * that a later query of the i_version will result in a different value if - * anything has changed. - * - * In this implementation, we fetch the current value, set the QUERIED flag and - * then try to swap it into place with a cmpxchg, if it wasn't already set. If - * that fails, we try again with the newly fetched value from the cmpxchg. - */ -static inline u64 -inode_query_iversion(struct inode *inode) -{ - u64 cur, new; - - cur = inode_peek_iversion_raw(inode); - do { - /* If flag is already set, then no need to swap */ - if (cur & I_VERSION_QUERIED) { - /* - * This barrier (and the implicit barrier in the - * cmpxchg below) pairs with the barrier in - * inode_maybe_inc_iversion(). - */ - smp_mb(); - break; - } - - new = cur | I_VERSION_QUERIED; - } while (!atomic64_try_cmpxchg(&inode->i_version, &cur, new)); - return cur >> I_VERSION_QUERIED_SHIFT; -} - /* * For filesystems without any sort of change attribute, the best we can * do is fake one up from the ctime: @@ -283,6 +247,8 @@ static inline u64 time_to_chattr(struct timespec64 *t) return chattr; } +u64 inode_query_iversion(struct inode *inode); + /** * inode_eq_iversion_raw - check whether the raw i_version counter has changed * @inode: inode to check