Merge patch series "fs: Move metadata bh tracking from address_space"

Jan Kara <jack@suse.cz> says:

This patch series cleans up the mess that has accumulated over the years in
metadata buffer_head tracking for inodes, moves the tracking into dedicated
structure in filesystem-private part of the inode (so that we don't use
private_list, private_data, and private_lock in struct address_space), and also
moves couple other users of private_data and private_list so these are removed
from struct address_space saving 3 longs in struct inode for 99% of inodes.  I
would like to get rid of private_lock in struct address_space as well however
the locking changes for buffer_heads are non-trivial there and the patch series
is long enough as is. So let's leave that for another time.

* patches from https://patch.msgid.link/20260326082428.31660-1-jack@suse.cz: (42 commits)
  fs: Drop i_private_list from address_space
  fs: Drop mapping_metadata_bhs from address space
  ext4: Track metadata bhs in fs-private inode part
  minix: Track metadata bhs in fs-private inode part
  udf: Track metadata bhs in fs-private inode part
  fat: Track metadata bhs in fs-private inode part
  bfs: Track metadata bhs in fs-private inode part
  affs: Track metadata bhs in fs-private inode part
  ext2: Track metadata bhs in fs-private inode part
  fs: Provide functions for handling mapping_metadata_bhs directly
  fs: Switch inode_has_buffers() to take mapping_metadata_bhs
  fs: Make bhs point to mapping_metadata_bhs
  fs: Move metadata bhs tracking to a separate struct
  fs: Fold fsync_buffers_list() into sync_mapping_buffers()
  fs: Drop osync_buffers_list()
  kvm: Use private inode list instead of i_private_list
  fs: Remove i_private_data
  aio: Stop using i_private_data and i_private_lock
  hugetlbfs: Stop using i_private_data
  fs: Stop using i_private_data for metadata bh tracking
  ...

Link: https://patch.msgid.link/20260326082428.31660-1-jack@suse.cz
Signed-off-by: Christian Brauner <brauner@kernel.org>

3 files changed, 23 insertions, 22 deletions

diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h
index b16b88bfbc3e..e4939e33b4b5 100644
--- a/include/linux/buffer_head.h
+++ b/include/linux/buffer_head.h
@@ -73,8 +73,8 @@ struct buffer_head {
 	bh_end_io_t *b_end_io;		/* I/O completion */
  	void *b_private;		/* reserved for b_end_io */
 	struct list_head b_assoc_buffers; /* associated with another mapping */
-	struct address_space *b_assoc_map;	/* mapping this buffer is
-						   associated with */
+	struct mapping_metadata_bhs *b_mmb; /* head of the list of metadata bhs
+					     * this buffer is associated with */
 	atomic_t b_count;		/* users using this buffer_head */
 	spinlock_t b_uptodate_lock;	/* Used by the first bh in a page, to
 					 * serialise IO completion of other
@@ -205,12 +205,12 @@ struct buffer_head *create_empty_buffers(struct folio *folio,
 void end_buffer_read_sync(struct buffer_head *bh, int uptodate);
 void end_buffer_write_sync(struct buffer_head *bh, int uptodate);
 
-/* Things to do with buffers at mapping->private_list */
-void mark_buffer_dirty_inode(struct buffer_head *bh, struct inode *inode);
-int generic_buffers_fsync_noflush(struct file *file, loff_t start, loff_t end,
-				  bool datasync);
-int generic_buffers_fsync(struct file *file, loff_t start, loff_t end,
-			  bool datasync);
+/* Things to do with metadata buffers list */
+void mmb_mark_buffer_dirty(struct buffer_head *bh, struct mapping_metadata_bhs *mmb);
+int mmb_fsync_noflush(struct file *file, struct mapping_metadata_bhs *mmb,
+		      loff_t start, loff_t end, bool datasync);
+int mmb_fsync(struct file *file, struct mapping_metadata_bhs *mmb,
+	      loff_t start, loff_t end, bool datasync);
 void clean_bdev_aliases(struct block_device *bdev, sector_t block,
 			sector_t len);
 static inline void clean_bdev_bh_alias(struct buffer_head *bh)
@@ -515,10 +515,10 @@ bool block_dirty_folio(struct address_space *mapping, struct folio *folio);
 
 void buffer_init(void);
 bool try_to_free_buffers(struct folio *folio);
-int inode_has_buffers(struct inode *inode);
-void invalidate_inode_buffers(struct inode *inode);
-int remove_inode_buffers(struct inode *inode);
-int sync_mapping_buffers(struct address_space *mapping);
+void mmb_init(struct mapping_metadata_bhs *mmb, struct address_space *mapping);
+bool mmb_has_buffers(struct mapping_metadata_bhs *mmb);
+void mmb_invalidate(struct mapping_metadata_bhs *mmb);
+int mmb_sync(struct mapping_metadata_bhs *mmb);
 void invalidate_bh_lrus(void);
 void invalidate_bh_lrus_cpu(void);
 bool has_bh_in_lru(int cpu, void *dummy);
@@ -528,10 +528,7 @@ extern int buffer_heads_over_limit;
 
 static inline void buffer_init(void) {}
 static inline bool try_to_free_buffers(struct folio *folio) { return true; }
-static inline int inode_has_buffers(struct inode *inode) { return 0; }
-static inline void invalidate_inode_buffers(struct inode *inode) {}
-static inline int remove_inode_buffers(struct inode *inode) { return 1; }
-static inline int sync_mapping_buffers(struct address_space *mapping) { return 0; }
+static inline int mmb_sync(struct mapping_metadata_bhs *mmb) { return 0; }
 static inline void invalidate_bh_lrus(void) {}
 static inline void invalidate_bh_lrus_cpu(void) {}
 static inline bool has_bh_in_lru(int cpu, void *dummy) { return false; }
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 8b3dd145b25e..a3bed26d066d 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -445,6 +445,13 @@ struct address_space_operations {
 
 extern const struct address_space_operations empty_aops;
 
+/* Structure for tracking metadata buffer heads associated with the mapping */
+struct mapping_metadata_bhs {
+	struct address_space *mapping;	/* Mapping bhs are associated with */
+	spinlock_t lock;	/* Lock protecting bh list */
+	struct list_head list;	/* The list of bhs (b_assoc_buffers) */
+};
+
 /**
  * struct address_space - Contents of a cacheable, mappable object.
  * @host: Owner, either the inode or the block_device.
@@ -464,8 +471,6 @@ extern const struct address_space_operations empty_aops;
  * @flags: Error bits and flags (AS_*).
  * @wb_err: The most recent error which has occurred.
  * @i_private_lock: For use by the owner of the address_space.
- * @i_private_list: For use by the owner of the address_space.
- * @i_private_data: For use by the owner of the address_space.
  */
 struct address_space {
 	struct inode		*host;
@@ -484,9 +489,7 @@ struct address_space {
 	unsigned long		flags;
 	errseq_t		wb_err;
 	spinlock_t		i_private_lock;
-	struct list_head	i_private_list;
 	struct rw_semaphore	i_mmap_rwsem;
-	void *			i_private_data;
 } __attribute__((aligned(sizeof(long)))) __randomize_layout;
 	/*
 	 * On most architectures that alignment is already the case; but
@@ -3295,8 +3298,8 @@ void simple_offset_destroy(struct offset_ctx *octx);
 
 extern const struct file_operations simple_offset_dir_operations;
 
-extern int __generic_file_fsync(struct file *, loff_t, loff_t, int);
-extern int generic_file_fsync(struct file *, loff_t, loff_t, int);
+extern int simple_fsync_noflush(struct file *, loff_t, loff_t, int);
+extern int simple_fsync(struct file *, loff_t, loff_t, int);
 
 extern int generic_check_addressable(unsigned, u64);
 
diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index 65910437be1c..fc5462fe943f 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -518,6 +518,7 @@ static inline struct hugetlbfs_sb_info *HUGETLBFS_SB(struct super_block *sb)
 
 struct hugetlbfs_inode_info {
 	struct inode vfs_inode;
+	struct resv_map *resv_map;
 	unsigned int seals;
 };