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Commit 090fd5b1 authored by Ryusuke Konishi's avatar Ryusuke Konishi
Browse files

nilfs2: get rid of back pointer to writable sb instance 



Nilfs object holds a back pointer to a writable super block instance
in nilfs->ns_writer, and this became eliminable since sb is now made
per device and all inodes have a valid pointer to it.

This deletes the ns_writer pointer and a reader/writer semaphore
protecting it.

Signed-off-by: default avatarRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
parent c6e07188

fs/nilfs2/mdt.c

+2 −31
Original line number Diff line number Diff line
@@ -78,25 +78,11 @@ static int nilfs_mdt_create_block(struct inode *inode, unsigned long block, 
						     struct buffer_head *,

						     void *))

{

	struct the_nilfs *nilfs = NILFS_I_NILFS(inode);

	struct super_block *sb = inode->i_sb;

	struct nilfs_transaction_info ti;

	struct buffer_head *bh;

	int err;



	if (!sb) {

		/*

		 * Make sure this function is not called from any

		 * read-only context.

		 */

		if (!nilfs->ns_writer) {

			WARN_ON(1);

			err = -EROFS;

			goto out;

		}

		sb = nilfs->ns_writer->s_super;

	}



	nilfs_transaction_begin(sb, &ti, 0);



	err = -ENOMEM;
@@ -112,7 +98,7 @@ static int nilfs_mdt_create_block(struct inode *inode, unsigned long block, 
	if (buffer_uptodate(bh))

		goto failed_bh;



	bh->b_bdev = nilfs->ns_bdev;

	bh->b_bdev = sb->s_bdev;

	err = nilfs_mdt_insert_new_block(inode, block, bh, init_block);

	if (likely(!err)) {

		get_bh(bh);
@@ -129,7 +115,7 @@ static int nilfs_mdt_create_block(struct inode *inode, unsigned long block, 
		err = nilfs_transaction_commit(sb);

	else

		nilfs_transaction_abort(sb);

 out:



	return err;

}
@@ -398,8 +384,6 @@ nilfs_mdt_write_page(struct page *page, struct writeback_control *wbc) 
{

	struct inode *inode;

	struct super_block *sb;

	struct the_nilfs *nilfs;

	struct nilfs_sb_info *writer = NULL;

	int err = 0;



	redirty_page_for_writepage(wbc, page);
@@ -410,25 +394,12 @@ nilfs_mdt_write_page(struct page *page, struct writeback_control *wbc) 
		return 0;



	sb = inode->i_sb;

	nilfs = NILFS_SB(sb)->s_nilfs;



	if (!sb) {

		down_read(&nilfs->ns_writer_sem);

		writer = nilfs->ns_writer;

		if (!writer) {

			up_read(&nilfs->ns_writer_sem);

			return -EROFS;

		}

		sb = writer->s_super;

	}



	if (wbc->sync_mode == WB_SYNC_ALL)

		err = nilfs_construct_segment(sb);

	else if (wbc->for_reclaim)

		nilfs_flush_segment(sb, inode->i_ino);



	if (writer)

		up_read(&nilfs->ns_writer_sem);

	return err;

}

fs/nilfs2/recovery.c

+0 −4
Original line number Diff line number Diff line
@@ -440,7 +440,6 @@ static int nilfs_prepare_segment_for_recovery(struct the_nilfs *nilfs, 
	segnum[2] = ri->ri_segnum;

	segnum[3] = ri->ri_nextnum;



	nilfs_attach_writer(nilfs, sbi);

	/*

	 * Releasing the next segment of the latest super root.

	 * The next segment is invalidated by this recovery.
@@ -480,7 +479,6 @@ static int nilfs_prepare_segment_for_recovery(struct the_nilfs *nilfs, 


 failed:

	/* No need to recover sufile because it will be destroyed on error */

	nilfs_detach_writer(nilfs, sbi);

	return err;

}
@@ -599,7 +597,6 @@ static int nilfs_do_roll_forward(struct the_nilfs *nilfs, 
	};

	int state = RF_INIT_ST;



	nilfs_attach_writer(nilfs, sbi);

	pseg_start = ri->ri_lsegs_start;

	seg_seq = ri->ri_lsegs_start_seq;

	segnum = nilfs_get_segnum_of_block(nilfs, pseg_start);
@@ -690,7 +687,6 @@ static int nilfs_do_roll_forward(struct the_nilfs *nilfs, 
 out:

	brelse(bh_sum);

	dispose_recovery_list(&dsync_blocks);

	nilfs_detach_writer(nilfs, sbi);

	return err;



 confused:

fs/nilfs2/segment.c

+0 −4
Original line number Diff line number Diff line
@@ -2799,7 +2799,6 @@ static void nilfs_segctor_destroy(struct nilfs_sc_info *sci) 
int nilfs_attach_segment_constructor(struct nilfs_sb_info *sbi,

				     struct nilfs_root *root)

{

	struct the_nilfs *nilfs = sbi->s_nilfs;

	int err;



	if (NILFS_SC(sbi)) {
@@ -2815,10 +2814,8 @@ int nilfs_attach_segment_constructor(struct nilfs_sb_info *sbi, 
	if (!sbi->s_sc_info)

		return -ENOMEM;



	nilfs_attach_writer(nilfs, sbi);

	err = nilfs_segctor_start_thread(NILFS_SC(sbi));

	if (err) {

		nilfs_detach_writer(nilfs, sbi);

		kfree(sbi->s_sc_info);

		sbi->s_sc_info = NULL;

	}
@@ -2855,5 +2852,4 @@ void nilfs_detach_segment_constructor(struct nilfs_sb_info *sbi) 
	up_write(&nilfs->ns_segctor_sem);



	nilfs_dispose_list(sbi, &garbage_list, 1);

	nilfs_detach_writer(nilfs, sbi);

}

fs/nilfs2/the_nilfs.c

+0 −1
Original line number Diff line number Diff line
@@ -75,7 +75,6 @@ struct the_nilfs *alloc_nilfs(struct block_device *bdev) 
	nilfs->ns_bdev = bdev;

	atomic_set(&nilfs->ns_ndirtyblks, 0);

	init_rwsem(&nilfs->ns_sem);

	init_rwsem(&nilfs->ns_writer_sem);

	INIT_LIST_HEAD(&nilfs->ns_gc_inodes);

	spin_lock_init(&nilfs->ns_last_segment_lock);

	nilfs->ns_cptree = RB_ROOT;

fs/nilfs2/the_nilfs.h

+0 −21
Original line number Diff line number Diff line
@@ -48,9 +48,7 @@ enum { 
 * @ns_flags: flags

 * @ns_bdev: block device

 * @ns_bdi: backing dev info

 * @ns_writer: back pointer to writable nilfs_sb_info

 * @ns_sem: semaphore for shared states

 * @ns_writer_sem: semaphore protecting ns_writer attach/detach

 * @ns_sbh: buffer heads of on-disk super blocks

 * @ns_sbp: pointers to super block data

 * @ns_sbwtime: previous write time of super block
@@ -93,9 +91,7 @@ struct the_nilfs { 


	struct block_device    *ns_bdev;

	struct backing_dev_info *ns_bdi;

	struct nilfs_sb_info   *ns_writer;

	struct rw_semaphore	ns_sem;

	struct rw_semaphore	ns_writer_sem;



	/*

	 * used for
@@ -252,23 +248,6 @@ static inline void nilfs_get_root(struct nilfs_root *root) 
	atomic_inc(&root->count);

}



static inline void

nilfs_attach_writer(struct the_nilfs *nilfs, struct nilfs_sb_info *sbi)

{

	down_write(&nilfs->ns_writer_sem);

	nilfs->ns_writer = sbi;

	up_write(&nilfs->ns_writer_sem);

}



static inline void

nilfs_detach_writer(struct the_nilfs *nilfs, struct nilfs_sb_info *sbi)

{

	down_write(&nilfs->ns_writer_sem);

	if (sbi == nilfs->ns_writer)

		nilfs->ns_writer = NULL;

	up_write(&nilfs->ns_writer_sem);

}



static inline int nilfs_valid_fs(struct the_nilfs *nilfs)

{

	unsigned valid_fs;