| Message ID | 20211202084856.1285285-3-ruansy.fnst@fujitsu.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | fsdax: introduce fs query to support reflink | expand |
On Thu, Dec 2, 2021 at 12:49 AM Shiyang Ruan <ruansy.fnst@fujitsu.com> wrote: > > To easily track filesystem from a pmem device, we introduce a holder for > dax_device structure, and also its operation. This holder is used to > remember who is using this dax_device: > - When it is the backend of a filesystem, the holder will be the > superblock of this filesystem. > - When this pmem device is one of the targets in a mapped device, the > holder will be this mapped device. In this case, the mapped device > has its own dax_device and it will follow the first rule. So that we > can finally track to the filesystem we needed. > > The holder and holder_ops will be set when filesystem is being mounted, > or an target device is being activated. > > Signed-off-by: Shiyang Ruan <ruansy.fnst@fujitsu.com> > --- > drivers/dax/super.c | 61 +++++++++++++++++++++++++++++++++++++++++++++ > include/linux/dax.h | 25 +++++++++++++++++++ > 2 files changed, 86 insertions(+) > > diff --git a/drivers/dax/super.c b/drivers/dax/super.c > index 719e77b2c2d4..a19fcc0a54f3 100644 > --- a/drivers/dax/super.c > +++ b/drivers/dax/super.c > @@ -20,15 +20,20 @@ > * @inode: core vfs > * @cdev: optional character interface for "device dax" > * @private: dax driver private data > + * @holder_data: holder of a dax_device: could be filesystem or mapped device > * @flags: state and boolean properties > + * @ops: operations for dax_device > + * @holder_ops: operations for the inner holder > */ > struct dax_device { > struct inode inode; > struct cdev cdev; > void *private; > struct percpu_rw_semaphore rwsem; > + void *holder_data; > unsigned long flags; > const struct dax_operations *ops; > + const struct dax_holder_operations *holder_ops; > }; > > static dev_t dax_devt; > @@ -190,6 +195,29 @@ int dax_zero_page_range(struct dax_device *dax_dev, pgoff_t pgoff, > } > EXPORT_SYMBOL_GPL(dax_zero_page_range); > > +int dax_holder_notify_failure(struct dax_device *dax_dev, u64 off, > + u64 len, int mf_flags) > +{ > + int rc; > + > + dax_read_lock(dax_dev); > + if (!dax_alive(dax_dev)) { > + rc = -ENXIO; > + goto out; > + } > + > + if (!dax_dev->holder_ops) { > + rc = -EOPNOTSUPP; > + goto out; > + } > + > + rc = dax_dev->holder_ops->notify_failure(dax_dev, off, len, mf_flags); > +out: > + dax_read_unlock(dax_dev); > + return rc; > +} > +EXPORT_SYMBOL_GPL(dax_holder_notify_failure); > + > #ifdef CONFIG_ARCH_HAS_PMEM_API > void arch_wb_cache_pmem(void *addr, size_t size); > void dax_flush(struct dax_device *dax_dev, void *addr, size_t size) > @@ -252,6 +280,10 @@ void kill_dax(struct dax_device *dax_dev) > return; > dax_write_lock(dax_dev); > clear_bit(DAXDEV_ALIVE, &dax_dev->flags); > + > + /* clear holder data */ > + dax_dev->holder_ops = NULL; > + dax_dev->holder_data = NULL; > dax_write_unlock(dax_dev); > } > EXPORT_SYMBOL_GPL(kill_dax); > @@ -399,6 +431,35 @@ void put_dax(struct dax_device *dax_dev) > } > EXPORT_SYMBOL_GPL(put_dax); > > +void dax_set_holder(struct dax_device *dax_dev, void *holder, > + const struct dax_holder_operations *ops) > +{ > + dax_write_lock(dax_dev); > + if (!dax_alive(dax_dev)) > + goto out; > + > + dax_dev->holder_data = holder; > + dax_dev->holder_ops = ops; > +out: > + dax_write_unlock(dax_dev); Why does this need to be a write_lock()? This is just like any other dax_operation that can only operate while the dax device is alive. > +} > +EXPORT_SYMBOL_GPL(dax_set_holder); > + > +void *dax_get_holder(struct dax_device *dax_dev) > +{ > + void *holder = NULL; > + > + dax_read_lock(dax_dev); > + if (!dax_alive(dax_dev)) > + goto out; > + > + holder = dax_dev->holder_data; > +out: > + dax_read_unlock(dax_dev); > + return holder; The read_lock should be held outside of this helper. I.e. the caller of this will already want to do: dax_read_lock() dax_get_holder() *do holder operation* dax_read_unlock() <-- now device can finalize kill_dax(). > +} > +EXPORT_SYMBOL_GPL(dax_get_holder); > + > /** > * inode_dax: convert a public inode into its dax_dev > * @inode: An inode with i_cdev pointing to a dax_dev > diff --git a/include/linux/dax.h b/include/linux/dax.h > index 8414a08dcbea..f01684a63447 100644 > --- a/include/linux/dax.h > +++ b/include/linux/dax.h > @@ -44,6 +44,21 @@ struct dax_operations { > #if IS_ENABLED(CONFIG_DAX) > struct dax_device *alloc_dax(void *private, const struct dax_operations *ops, > unsigned long flags); > +struct dax_holder_operations { > + /* > + * notify_failure - notify memory failure into inner holder device > + * @dax_dev: the dax device which contains the holder > + * @offset: offset on this dax device where memory failure occurs > + * @len: length of this memory failure event > + * @flags: action flags for memory failure handler > + */ > + int (*notify_failure)(struct dax_device *dax_dev, u64 offset, > + u64 len, int mf_flags); > +}; > + > +void dax_set_holder(struct dax_device *dax_dev, void *holder, > + const struct dax_holder_operations *ops); > +void *dax_get_holder(struct dax_device *dax_dev); > void put_dax(struct dax_device *dax_dev); > void kill_dax(struct dax_device *dax_dev); > void dax_write_cache(struct dax_device *dax_dev, bool wc); > @@ -71,6 +86,14 @@ static inline bool daxdev_mapping_supported(struct vm_area_struct *vma, > return dax_synchronous(dax_dev); > } > #else > +static inline void dax_set_holder(struct dax_device *dax_dev, void *holder, > + const struct dax_holder_operations *ops) > +{ > +} > +static inline void *dax_get_holder(struct dax_device *dax_dev) > +{ > + return NULL; > +} > static inline struct dax_device *alloc_dax(void *private, > const struct dax_operations *ops, unsigned long flags) > { > @@ -199,6 +222,8 @@ size_t dax_copy_to_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr, > size_t bytes, struct iov_iter *i); > int dax_zero_page_range(struct dax_device *dax_dev, pgoff_t pgoff, > size_t nr_pages); > +int dax_holder_notify_failure(struct dax_device *dax_dev, u64 off, u64 len, > + int mf_flags); > void dax_flush(struct dax_device *dax_dev, void *addr, size_t size); > > ssize_t dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter, > -- > 2.34.0 > > >
diff --git a/drivers/dax/super.c b/drivers/dax/super.c index 719e77b2c2d4..a19fcc0a54f3 100644 --- a/drivers/dax/super.c +++ b/drivers/dax/super.c @@ -20,15 +20,20 @@ * @inode: core vfs * @cdev: optional character interface for "device dax" * @private: dax driver private data + * @holder_data: holder of a dax_device: could be filesystem or mapped device * @flags: state and boolean properties + * @ops: operations for dax_device + * @holder_ops: operations for the inner holder */ struct dax_device { struct inode inode; struct cdev cdev; void *private; struct percpu_rw_semaphore rwsem; + void *holder_data; unsigned long flags; const struct dax_operations *ops; + const struct dax_holder_operations *holder_ops; }; static dev_t dax_devt; @@ -190,6 +195,29 @@ int dax_zero_page_range(struct dax_device *dax_dev, pgoff_t pgoff, } EXPORT_SYMBOL_GPL(dax_zero_page_range); +int dax_holder_notify_failure(struct dax_device *dax_dev, u64 off, + u64 len, int mf_flags) +{ + int rc; + + dax_read_lock(dax_dev); + if (!dax_alive(dax_dev)) { + rc = -ENXIO; + goto out; + } + + if (!dax_dev->holder_ops) { + rc = -EOPNOTSUPP; + goto out; + } + + rc = dax_dev->holder_ops->notify_failure(dax_dev, off, len, mf_flags); +out: + dax_read_unlock(dax_dev); + return rc; +} +EXPORT_SYMBOL_GPL(dax_holder_notify_failure); + #ifdef CONFIG_ARCH_HAS_PMEM_API void arch_wb_cache_pmem(void *addr, size_t size); void dax_flush(struct dax_device *dax_dev, void *addr, size_t size) @@ -252,6 +280,10 @@ void kill_dax(struct dax_device *dax_dev) return; dax_write_lock(dax_dev); clear_bit(DAXDEV_ALIVE, &dax_dev->flags); + + /* clear holder data */ + dax_dev->holder_ops = NULL; + dax_dev->holder_data = NULL; dax_write_unlock(dax_dev); } EXPORT_SYMBOL_GPL(kill_dax); @@ -399,6 +431,35 @@ void put_dax(struct dax_device *dax_dev) } EXPORT_SYMBOL_GPL(put_dax); +void dax_set_holder(struct dax_device *dax_dev, void *holder, + const struct dax_holder_operations *ops) +{ + dax_write_lock(dax_dev); + if (!dax_alive(dax_dev)) + goto out; + + dax_dev->holder_data = holder; + dax_dev->holder_ops = ops; +out: + dax_write_unlock(dax_dev); +} +EXPORT_SYMBOL_GPL(dax_set_holder); + +void *dax_get_holder(struct dax_device *dax_dev) +{ + void *holder = NULL; + + dax_read_lock(dax_dev); + if (!dax_alive(dax_dev)) + goto out; + + holder = dax_dev->holder_data; +out: + dax_read_unlock(dax_dev); + return holder; +} +EXPORT_SYMBOL_GPL(dax_get_holder); + /** * inode_dax: convert a public inode into its dax_dev * @inode: An inode with i_cdev pointing to a dax_dev diff --git a/include/linux/dax.h b/include/linux/dax.h index 8414a08dcbea..f01684a63447 100644 --- a/include/linux/dax.h +++ b/include/linux/dax.h @@ -44,6 +44,21 @@ struct dax_operations { #if IS_ENABLED(CONFIG_DAX) struct dax_device *alloc_dax(void *private, const struct dax_operations *ops, unsigned long flags); +struct dax_holder_operations { + /* + * notify_failure - notify memory failure into inner holder device + * @dax_dev: the dax device which contains the holder + * @offset: offset on this dax device where memory failure occurs + * @len: length of this memory failure event + * @flags: action flags for memory failure handler + */ + int (*notify_failure)(struct dax_device *dax_dev, u64 offset, + u64 len, int mf_flags); +}; + +void dax_set_holder(struct dax_device *dax_dev, void *holder, + const struct dax_holder_operations *ops); +void *dax_get_holder(struct dax_device *dax_dev); void put_dax(struct dax_device *dax_dev); void kill_dax(struct dax_device *dax_dev); void dax_write_cache(struct dax_device *dax_dev, bool wc); @@ -71,6 +86,14 @@ static inline bool daxdev_mapping_supported(struct vm_area_struct *vma, return dax_synchronous(dax_dev); } #else +static inline void dax_set_holder(struct dax_device *dax_dev, void *holder, + const struct dax_holder_operations *ops) +{ +} +static inline void *dax_get_holder(struct dax_device *dax_dev) +{ + return NULL; +} static inline struct dax_device *alloc_dax(void *private, const struct dax_operations *ops, unsigned long flags) { @@ -199,6 +222,8 @@ size_t dax_copy_to_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr, size_t bytes, struct iov_iter *i); int dax_zero_page_range(struct dax_device *dax_dev, pgoff_t pgoff, size_t nr_pages); +int dax_holder_notify_failure(struct dax_device *dax_dev, u64 off, u64 len, + int mf_flags); void dax_flush(struct dax_device *dax_dev, void *addr, size_t size); ssize_t dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter,
To easily track filesystem from a pmem device, we introduce a holder for dax_device structure, and also its operation. This holder is used to remember who is using this dax_device: - When it is the backend of a filesystem, the holder will be the superblock of this filesystem. - When this pmem device is one of the targets in a mapped device, the holder will be this mapped device. In this case, the mapped device has its own dax_device and it will follow the first rule. So that we can finally track to the filesystem we needed. The holder and holder_ops will be set when filesystem is being mounted, or an target device is being activated. Signed-off-by: Shiyang Ruan <ruansy.fnst@fujitsu.com> --- drivers/dax/super.c | 61 +++++++++++++++++++++++++++++++++++++++++++++ include/linux/dax.h | 25 +++++++++++++++++++ 2 files changed, 86 insertions(+)