Borrowed from: https://lore.kernel.org/linux-fsdevel/20240213093713.1753368-2-kernel@xxxxxxxxxxxxxxxx/ (credit given in due course) We will need to be able to only use a single folio order for buffered atomic writes, so allow the mapping folio order min and max be set. We still have the restriction of not being able to support order-1 folios - it will be required to lift this limit at some stage. Signed-off-by: John Garry <john.g.garry@xxxxxxxxxx> --- fs/xfs/xfs_icache.c | 10 ++++++---- include/linux/pagemap.h | 20 +++++++++++++------- mm/filemap.c | 8 +++++++- 3 files changed, 26 insertions(+), 12 deletions(-) diff --git a/fs/xfs/xfs_icache.c b/fs/xfs/xfs_icache.c index 8fb5cf0f5a09..6186887bd6ff 100644 --- a/fs/xfs/xfs_icache.c +++ b/fs/xfs/xfs_icache.c @@ -89,8 +89,9 @@ xfs_inode_alloc( /* VFS doesn't initialise i_mode or i_state! */ VFS_I(ip)->i_mode = 0; VFS_I(ip)->i_state = 0; - mapping_set_folio_min_order(VFS_I(ip)->i_mapping, - M_IGEO(mp)->min_folio_order); + mapping_set_folio_orders(VFS_I(ip)->i_mapping, + M_IGEO(mp)->min_folio_order, + MAX_PAGECACHE_ORDER); XFS_STATS_INC(mp, vn_active); ASSERT(atomic_read(&ip->i_pincount) == 0); @@ -325,8 +326,9 @@ xfs_reinit_inode( inode->i_rdev = dev; inode->i_uid = uid; inode->i_gid = gid; - mapping_set_folio_min_order(inode->i_mapping, - M_IGEO(mp)->min_folio_order); + mapping_set_folio_orders(inode->i_mapping, + M_IGEO(mp)->min_folio_order, + MAX_PAGECACHE_ORDER); return error; } diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h index fc8eb9c94e9c..c22455fa28a1 100644 --- a/include/linux/pagemap.h +++ b/include/linux/pagemap.h @@ -363,9 +363,10 @@ static inline void mapping_set_gfp_mask(struct address_space *m, gfp_t mask) #endif /* - * mapping_set_folio_min_order() - Set the minimum folio order + * mapping_set_folio_orders() - Set the minimum and max folio order * @mapping: The address_space. * @min: Minimum folio order (between 0-MAX_PAGECACHE_ORDER inclusive). + * @max: Maximum folio order (between 0-MAX_PAGECACHE_ORDER inclusive). * * The filesystem should call this function in its inode constructor to * indicate which base size of folio the VFS can use to cache the contents @@ -376,15 +377,20 @@ static inline void mapping_set_gfp_mask(struct address_space *m, gfp_t mask) * Context: This should not be called while the inode is active as it * is non-atomic. */ -static inline void mapping_set_folio_min_order(struct address_space *mapping, - unsigned int min) + +static inline void mapping_set_folio_orders(struct address_space *mapping, + unsigned int min, unsigned int max) { - if (min > MAX_PAGECACHE_ORDER) - min = MAX_PAGECACHE_ORDER; + if (min == 1) + min = 2; + if (max < min) + max = min; + if (max > MAX_PAGECACHE_ORDER) + max = MAX_PAGECACHE_ORDER; mapping->flags = (mapping->flags & ~AS_FOLIO_ORDER_MASK) | (min << AS_FOLIO_ORDER_MIN) | - (MAX_PAGECACHE_ORDER << AS_FOLIO_ORDER_MAX); + (max << AS_FOLIO_ORDER_MAX); } /** @@ -400,7 +406,7 @@ static inline void mapping_set_folio_min_order(struct address_space *mapping, */ static inline void mapping_set_large_folios(struct address_space *mapping) { - mapping_set_folio_min_order(mapping, 0); + mapping_set_folio_orders(mapping, 0, MAX_PAGECACHE_ORDER); } static inline unsigned int mapping_max_folio_order(struct address_space *mapping) diff --git a/mm/filemap.c b/mm/filemap.c index d81530b0aac0..d5effe50ddcb 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -1898,9 +1898,15 @@ struct folio *__filemap_get_folio(struct address_space *mapping, pgoff_t index, no_page: if (!folio && (fgp_flags & FGP_CREAT)) { unsigned int min_order = mapping_min_folio_order(mapping); - unsigned int order = max(min_order, FGF_GET_ORDER(fgp_flags)); + unsigned int max_order = mapping_max_folio_order(mapping); + unsigned int order = FGF_GET_ORDER(fgp_flags); int err; + if (order > max_order) + order = max_order; + else if (order < min_order) + order = max_order; + index = mapping_align_start_index(mapping, index); if ((fgp_flags & FGP_WRITE) && mapping_can_writeback(mapping)) -- 2.31.1
