| Message ID | 152066489984.40260.2215636951958334858.stgit@dwillia2-desk3.amr.corp.intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
> +int dax_set_page_dirty(struct page *page) > +{ > + /* > + * Unlike __set_page_dirty_no_writeback that handles dirty page > + * tracking in the page object, dax does all dirty tracking in > + * the inode address_space in response to mkwrite faults. In the > + * dax case we only need to worry about potentially dirty CPU > + * caches, not dirty page cache pages to write back. > + * > + * This callback is defined to prevent fallback to > + * __set_page_dirty_buffers() in set_page_dirty(). > + */ > + return 0; > +} Make this a generic noop_set_page_dirty maybe? > +EXPORT_SYMBOL(dax_set_page_dirty); > + > +void dax_invalidatepage(struct page *page, unsigned int offset, > + unsigned int length) > +{ > + /* > + * There is no page cache to invalidate in the dax case, however > + * we need this callback defined to prevent falling back to > + * block_invalidatepage() in do_invalidatepage(). > + */ > +} Same here. > +EXPORT_SYMBOL(dax_invalidatepage); And EXPORT_SYMBOL_GPL for anything dax-related, please. > +const struct address_space_operations xfs_dax_aops = { > + .writepages = xfs_vm_writepages, Please split out the DAX case from xfs_vm_writepages. This patch should probably also split into VFS and XFS parts.
On Sat, Mar 10, 2018 at 1:46 AM, Christoph Hellwig <hch@lst.de> wrote: >> +int dax_set_page_dirty(struct page *page) >> +{ >> + /* >> + * Unlike __set_page_dirty_no_writeback that handles dirty page >> + * tracking in the page object, dax does all dirty tracking in >> + * the inode address_space in response to mkwrite faults. In the >> + * dax case we only need to worry about potentially dirty CPU >> + * caches, not dirty page cache pages to write back. >> + * >> + * This callback is defined to prevent fallback to >> + * __set_page_dirty_buffers() in set_page_dirty(). >> + */ >> + return 0; >> +} > > Make this a generic noop_set_page_dirty maybe? > >> +EXPORT_SYMBOL(dax_set_page_dirty); >> + >> +void dax_invalidatepage(struct page *page, unsigned int offset, >> + unsigned int length) >> +{ >> + /* >> + * There is no page cache to invalidate in the dax case, however >> + * we need this callback defined to prevent falling back to >> + * block_invalidatepage() in do_invalidatepage(). >> + */ >> +} > > Same here. I guess I'm not sure what you mean. These nops are specific to dax I don't think they make sense in another context besides dax. > >> +EXPORT_SYMBOL(dax_invalidatepage); > > And EXPORT_SYMBOL_GPL for anything dax-related, please. > >> +const struct address_space_operations xfs_dax_aops = { >> + .writepages = xfs_vm_writepages, > > Please split out the DAX case from xfs_vm_writepages. Will do. > This patch should probably also split into VFS and XFS parts. Ok.
On Sat, Mar 10, 2018 at 9:40 AM, Dan Williams <dan.j.williams@intel.com> wrote: > On Sat, Mar 10, 2018 at 1:46 AM, Christoph Hellwig <hch@lst.de> wrote: >>> +int dax_set_page_dirty(struct page *page) >>> +{ >>> + /* >>> + * Unlike __set_page_dirty_no_writeback that handles dirty page >>> + * tracking in the page object, dax does all dirty tracking in >>> + * the inode address_space in response to mkwrite faults. In the >>> + * dax case we only need to worry about potentially dirty CPU >>> + * caches, not dirty page cache pages to write back. >>> + * >>> + * This callback is defined to prevent fallback to >>> + * __set_page_dirty_buffers() in set_page_dirty(). >>> + */ >>> + return 0; >>> +} >> >> Make this a generic noop_set_page_dirty maybe? >> >>> +EXPORT_SYMBOL(dax_set_page_dirty); >>> + >>> +void dax_invalidatepage(struct page *page, unsigned int offset, >>> + unsigned int length) >>> +{ >>> + /* >>> + * There is no page cache to invalidate in the dax case, however >>> + * we need this callback defined to prevent falling back to >>> + * block_invalidatepage() in do_invalidatepage(). >>> + */ >>> +} >> >> Same here. > > I guess I'm not sure what you mean. These nops are specific to dax I > don't think they make sense in another context besides dax. > I did the rename, and am housing these in fs/dax.c, I assume that's what you wanted.
On Sun, Mar 11, 2018 at 12:16:25PM -0700, Dan Williams wrote: > I did the rename, and am housing these in fs/dax.c, I assume that's > what you wanted. libfs.c would seem ok to, but we're into micro-management land now :)
diff --git a/fs/dax.c b/fs/dax.c index b646a46e4d12..ba02772fccbc 100644 --- a/fs/dax.c +++ b/fs/dax.c @@ -46,6 +46,33 @@ #define PG_PMD_COLOUR ((PMD_SIZE >> PAGE_SHIFT) - 1) #define PG_PMD_NR (PMD_SIZE >> PAGE_SHIFT) +int dax_set_page_dirty(struct page *page) +{ + /* + * Unlike __set_page_dirty_no_writeback that handles dirty page + * tracking in the page object, dax does all dirty tracking in + * the inode address_space in response to mkwrite faults. In the + * dax case we only need to worry about potentially dirty CPU + * caches, not dirty page cache pages to write back. + * + * This callback is defined to prevent fallback to + * __set_page_dirty_buffers() in set_page_dirty(). + */ + return 0; +} +EXPORT_SYMBOL(dax_set_page_dirty); + +void dax_invalidatepage(struct page *page, unsigned int offset, + unsigned int length) +{ + /* + * There is no page cache to invalidate in the dax case, however + * we need this callback defined to prevent falling back to + * block_invalidatepage() in do_invalidatepage(). + */ +} +EXPORT_SYMBOL(dax_invalidatepage); + static wait_queue_head_t wait_table[DAX_WAIT_TABLE_ENTRIES]; static int __init init_dax_wait_table(void) diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c index 9c6a830da0ee..5788b680fa01 100644 --- a/fs/xfs/xfs_aops.c +++ b/fs/xfs/xfs_aops.c @@ -1505,3 +1505,10 @@ const struct address_space_operations xfs_address_space_operations = { .is_partially_uptodate = block_is_partially_uptodate, .error_remove_page = generic_error_remove_page, }; + +const struct address_space_operations xfs_dax_aops = { + .writepages = xfs_vm_writepages, + .direct_IO = xfs_vm_direct_IO, + .set_page_dirty = dax_set_page_dirty, + .invalidatepage = dax_invalidatepage, +}; diff --git a/fs/xfs/xfs_aops.h b/fs/xfs/xfs_aops.h index 88c85ea63da0..69346d460dfa 100644 --- a/fs/xfs/xfs_aops.h +++ b/fs/xfs/xfs_aops.h @@ -54,6 +54,7 @@ struct xfs_ioend { }; extern const struct address_space_operations xfs_address_space_operations; +extern const struct address_space_operations xfs_dax_aops; int xfs_setfilesize(struct xfs_inode *ip, xfs_off_t offset, size_t size); diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c index 56475fcd76f2..951e84df5576 100644 --- a/fs/xfs/xfs_iops.c +++ b/fs/xfs/xfs_iops.c @@ -1272,7 +1272,10 @@ xfs_setup_iops( case S_IFREG: inode->i_op = &xfs_inode_operations; inode->i_fop = &xfs_file_operations; - inode->i_mapping->a_ops = &xfs_address_space_operations; + if (IS_DAX(inode)) + inode->i_mapping->a_ops = &xfs_dax_aops; + else + inode->i_mapping->a_ops = &xfs_address_space_operations; break; case S_IFDIR: if (xfs_sb_version_hasasciici(&XFS_M(inode->i_sb)->m_sb)) diff --git a/include/linux/dax.h b/include/linux/dax.h index 0185ecdae135..3045c0d9c804 100644 --- a/include/linux/dax.h +++ b/include/linux/dax.h @@ -57,6 +57,9 @@ static inline void fs_put_dax(struct dax_device *dax_dev) } struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev); +int dax_set_page_dirty(struct page *page); +void dax_invalidatepage(struct page *page, unsigned int offset, + unsigned int length); #else static inline int bdev_dax_supported(struct super_block *sb, int blocksize) { @@ -76,6 +79,9 @@ static inline struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev) { return NULL; } + +#define dax_set_page_dirty NULL +#define dax_invalidatepage NULL #endif int dax_read_lock(void);
In preparation for the dax implementation to start associating dax pages to inodes via page->mapping, we need to provide a 'struct address_space_operations' instance for dax. Otherwise, direct-I/O triggers incorrect page cache assumptions and warnings like the following: WARNING: CPU: 27 PID: 1783 at fs/xfs/xfs_aops.c:1468 xfs_vm_set_page_dirty+0xf3/0x1b0 [xfs] [..] CPU: 27 PID: 1783 Comm: dma-collision Tainted: G O 4.15.0-rc2+ #984 [..] Call Trace: set_page_dirty_lock+0x40/0x60 bio_set_pages_dirty+0x37/0x50 iomap_dio_actor+0x2b7/0x3b0 ? iomap_dio_zero+0x110/0x110 iomap_apply+0xa4/0x110 iomap_dio_rw+0x29e/0x3b0 ? iomap_dio_zero+0x110/0x110 ? xfs_file_dio_aio_read+0x7c/0x1a0 [xfs] xfs_file_dio_aio_read+0x7c/0x1a0 [xfs] xfs_file_read_iter+0xa0/0xc0 [xfs] __vfs_read+0xf9/0x170 vfs_read+0xa6/0x150 SyS_pread64+0x93/0xb0 entry_SYSCALL_64_fastpath+0x1f/0x96 ...where the default set_page_dirty() handler assumes that dirty state is being tracked in 'struct page' flags. Cc: Jeff Moyer <jmoyer@redhat.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Matthew Wilcox <mawilcox@microsoft.com> Cc: Ross Zwisler <ross.zwisler@linux.intel.com> Suggested-by: Jan Kara <jack@suse.cz> Suggested-by: Dave Chinner <david@fromorbit.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com> --- fs/dax.c | 27 +++++++++++++++++++++++++++ fs/xfs/xfs_aops.c | 7 +++++++ fs/xfs/xfs_aops.h | 1 + fs/xfs/xfs_iops.c | 5 ++++- include/linux/dax.h | 6 ++++++ 5 files changed, 45 insertions(+), 1 deletion(-)