The patch titled Subject: nilfs2: fix buffer head leaks in calls to truncate_inode_pages() has been added to the -mm mm-hotfixes-unstable branch. Its filename is nilfs2-fix-buffer-head-leaks-in-calls-to-truncate_inode_pages.patch

This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches...

This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------ From: Ryusuke Konishi konishi.ryusuke@gmail.com Subject: nilfs2: fix buffer head leaks in calls to truncate_inode_pages() Date: Fri, 13 Dec 2024 01:43:28 +0900

When block_invalidatepage was converted to block_invalidate_folio, the fallback to block_invalidatepage in folio_invalidate() if the address_space_operations method invalidatepage (currently invalidate_folio) was not set, was removed.

Unfortunately, some pseudo-inodes in nilfs2 use empty_aops set by inode_init_always_gfp() as is, or explicitly set it to address_space_operations. Therefore, with this change, block_invalidatepage() is no longer called from folio_invalidate(), and as a result, the buffer_head structures attached to these pages/folios are no longer freed via try_to_free_buffers().

Thus, these buffer heads are now leaked by truncate_inode_pages(), which cleans up the page cache from inode evict(), etc.

Three types of caches use empty_aops: gc inode caches and the DAT shadow inode used by GC, and b-tree node caches. Of these, b-tree node caches explicitly call invalidate_mapping_pages() during cleanup, which involves calling try_to_free_buffers(), so the leak was not visible during normal operation but worsened when GC was performed.

Fix this issue by using address_space_operations with invalidate_folio set to block_invalidate_folio instead of empty_aops, which will ensure the same behavior as before.

Link: https://lkml.kernel.org/r/20241212164556.21338-1-konishi.ryusuke@gmail.com Fixes: 7ba13abbd31e ("fs: Turn block_invalidatepage into block_invalidate_folio") Signed-off-by: Ryusuke Konishi konishi.ryusuke@gmail.com Cc: stable@vger.kernel.org [5.18+] Signed-off-by: Andrew Morton akpm@linux-foundation.org ---

fs/nilfs2/btnode.c | 1 + fs/nilfs2/gcinode.c | 2 +- fs/nilfs2/inode.c | 5 +++++ fs/nilfs2/nilfs.h | 1 + 4 files changed, 8 insertions(+), 1 deletion(-)

--- a/fs/nilfs2/btnode.c~nilfs2-fix-buffer-head-leaks-in-calls-to-truncate_inode_pages +++ a/fs/nilfs2/btnode.c @@ -35,6 +35,7 @@ void nilfs_init_btnc_inode(struct inode ii->i_flags = 0; memset(&ii->i_bmap_data, 0, sizeof(struct nilfs_bmap)); mapping_set_gfp_mask(btnc_inode->i_mapping, GFP_NOFS); + btnc_inode->i_mapping->a_ops = &nilfs_buffer_cache_aops; }

void nilfs_btnode_cache_clear(struct address_space *btnc) --- a/fs/nilfs2/gcinode.c~nilfs2-fix-buffer-head-leaks-in-calls-to-truncate_inode_pages +++ a/fs/nilfs2/gcinode.c @@ -163,7 +163,7 @@ int nilfs_init_gcinode(struct inode *ino

inode->i_mode = S_IFREG; mapping_set_gfp_mask(inode->i_mapping, GFP_NOFS); - inode->i_mapping->a_ops = &empty_aops; + inode->i_mapping->a_ops = &nilfs_buffer_cache_aops;

ii->i_flags = 0; nilfs_bmap_init_gc(ii->i_bmap); --- a/fs/nilfs2/inode.c~nilfs2-fix-buffer-head-leaks-in-calls-to-truncate_inode_pages +++ a/fs/nilfs2/inode.c @@ -276,6 +276,10 @@ const struct address_space_operations ni .is_partially_uptodate = block_is_partially_uptodate, };

+const struct address_space_operations nilfs_buffer_cache_aops = { + .invalidate_folio = block_invalidate_folio, +}; + static int nilfs_insert_inode_locked(struct inode *inode, struct nilfs_root *root, unsigned long ino) @@ -681,6 +685,7 @@ struct inode *nilfs_iget_for_shadow(stru NILFS_I(s_inode)->i_flags = 0; memset(NILFS_I(s_inode)->i_bmap, 0, sizeof(struct nilfs_bmap)); mapping_set_gfp_mask(s_inode->i_mapping, GFP_NOFS); + s_inode->i_mapping->a_ops = &nilfs_buffer_cache_aops;

err = nilfs_attach_btree_node_cache(s_inode); if (unlikely(err)) { --- a/fs/nilfs2/nilfs.h~nilfs2-fix-buffer-head-leaks-in-calls-to-truncate_inode_pages +++ a/fs/nilfs2/nilfs.h @@ -401,6 +401,7 @@ extern const struct file_operations nilf extern const struct inode_operations nilfs_file_inode_operations; extern const struct file_operations nilfs_file_operations; extern const struct address_space_operations nilfs_aops; +extern const struct address_space_operations nilfs_buffer_cache_aops; extern const struct inode_operations nilfs_dir_inode_operations; extern const struct inode_operations nilfs_special_inode_operations; extern const struct inode_operations nilfs_symlink_inode_operations; _

Patches currently in -mm which might be from konishi.ryusuke@gmail.com are

nilfs2-fix-buffer-head-leaks-in-calls-to-truncate_inode_pages.patch