| Message ID | 20210607145236.31852-4-jack@suse.cz (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | fs: Hole punch vs page cache filling races | expand |
On Mon, Jun 07, 2021 at 04:52:14PM +0200, Jan Kara wrote: > Some operations such as reflinking blocks among files will need to lock > invalidate_lock for two mappings. Add helper functions to do that. > > Signed-off-by: Jan Kara <jack@suse.cz> Straightforward lift from xfs, though now with vfs lock ordering rules... Reviewed-by: Darrick J. Wong <djwong@kernel.org> --D > --- > include/linux/fs.h | 6 ++++++ > mm/filemap.c | 38 ++++++++++++++++++++++++++++++++++++++ > 2 files changed, 44 insertions(+) > > diff --git a/include/linux/fs.h b/include/linux/fs.h > index d8afbc9661d7..ddc11bafc183 100644 > --- a/include/linux/fs.h > +++ b/include/linux/fs.h > @@ -849,6 +849,12 @@ static inline void filemap_invalidate_unlock_shared( > void lock_two_nondirectories(struct inode *, struct inode*); > void unlock_two_nondirectories(struct inode *, struct inode*); > > +void filemap_invalidate_lock_two(struct address_space *mapping1, > + struct address_space *mapping2); > +void filemap_invalidate_unlock_two(struct address_space *mapping1, > + struct address_space *mapping2); > + > + > /* > * NOTE: in a 32bit arch with a preemptable kernel and > * an UP compile the i_size_read/write must be atomic > diff --git a/mm/filemap.c b/mm/filemap.c > index c8e7e451d81e..b8e9bccecd9f 100644 > --- a/mm/filemap.c > +++ b/mm/filemap.c > @@ -1009,6 +1009,44 @@ struct page *__page_cache_alloc(gfp_t gfp) > EXPORT_SYMBOL(__page_cache_alloc); > #endif > > +/* > + * filemap_invalidate_lock_two - lock invalidate_lock for two mappings > + * > + * Lock exclusively invalidate_lock of any passed mapping that is not NULL. > + * > + * @mapping1: the first mapping to lock > + * @mapping2: the second mapping to lock > + */ > +void filemap_invalidate_lock_two(struct address_space *mapping1, > + struct address_space *mapping2) > +{ > + if (mapping1 > mapping2) > + swap(mapping1, mapping2); > + if (mapping1) > + down_write(&mapping1->invalidate_lock); > + if (mapping2 && mapping1 != mapping2) > + down_write_nested(&mapping2->invalidate_lock, 1); > +} > +EXPORT_SYMBOL(filemap_invalidate_lock_two); > + > +/* > + * filemap_invalidate_unlock_two - unlock invalidate_lock for two mappings > + * > + * Unlock exclusive invalidate_lock of any passed mapping that is not NULL. > + * > + * @mapping1: the first mapping to unlock > + * @mapping2: the second mapping to unlock > + */ > +void filemap_invalidate_unlock_two(struct address_space *mapping1, > + struct address_space *mapping2) > +{ > + if (mapping1) > + up_write(&mapping1->invalidate_lock); > + if (mapping2 && mapping1 != mapping2) > + up_write(&mapping2->invalidate_lock); > +} > +EXPORT_SYMBOL(filemap_invalidate_unlock_two); > + > /* > * In order to wait for pages to become available there must be > * waitqueues associated with pages. By using a hash table of > -- > 2.26.2 >
diff --git a/include/linux/fs.h b/include/linux/fs.h index d8afbc9661d7..ddc11bafc183 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -849,6 +849,12 @@ static inline void filemap_invalidate_unlock_shared( void lock_two_nondirectories(struct inode *, struct inode*); void unlock_two_nondirectories(struct inode *, struct inode*); +void filemap_invalidate_lock_two(struct address_space *mapping1, + struct address_space *mapping2); +void filemap_invalidate_unlock_two(struct address_space *mapping1, + struct address_space *mapping2); + + /* * NOTE: in a 32bit arch with a preemptable kernel and * an UP compile the i_size_read/write must be atomic diff --git a/mm/filemap.c b/mm/filemap.c index c8e7e451d81e..b8e9bccecd9f 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -1009,6 +1009,44 @@ struct page *__page_cache_alloc(gfp_t gfp) EXPORT_SYMBOL(__page_cache_alloc); #endif +/* + * filemap_invalidate_lock_two - lock invalidate_lock for two mappings + * + * Lock exclusively invalidate_lock of any passed mapping that is not NULL. + * + * @mapping1: the first mapping to lock + * @mapping2: the second mapping to lock + */ +void filemap_invalidate_lock_two(struct address_space *mapping1, + struct address_space *mapping2) +{ + if (mapping1 > mapping2) + swap(mapping1, mapping2); + if (mapping1) + down_write(&mapping1->invalidate_lock); + if (mapping2 && mapping1 != mapping2) + down_write_nested(&mapping2->invalidate_lock, 1); +} +EXPORT_SYMBOL(filemap_invalidate_lock_two); + +/* + * filemap_invalidate_unlock_two - unlock invalidate_lock for two mappings + * + * Unlock exclusive invalidate_lock of any passed mapping that is not NULL. + * + * @mapping1: the first mapping to unlock + * @mapping2: the second mapping to unlock + */ +void filemap_invalidate_unlock_two(struct address_space *mapping1, + struct address_space *mapping2) +{ + if (mapping1) + up_write(&mapping1->invalidate_lock); + if (mapping2 && mapping1 != mapping2) + up_write(&mapping2->invalidate_lock); +} +EXPORT_SYMBOL(filemap_invalidate_unlock_two); + /* * In order to wait for pages to become available there must be * waitqueues associated with pages. By using a hash table of
Some operations such as reflinking blocks among files will need to lock invalidate_lock for two mappings. Add helper functions to do that. Signed-off-by: Jan Kara <jack@suse.cz> --- include/linux/fs.h | 6 ++++++ mm/filemap.c | 38 ++++++++++++++++++++++++++++++++++++++ 2 files changed, 44 insertions(+)