Commit 31b2ebc0 authored by Ritesh Harjani (IBM)'s avatar Ritesh Harjani (IBM) Committed by Jan Kara
Browse files

fs/buffer.c: Add generic_buffers_fsync*() implementation 



Some of the higher layers like iomap takes inode_lock() when calling
generic_write_sync().
Also writeback already happens from other paths without inode lock,
so it's difficult to say that we really need sync_mapping_buffers() to
take any inode locking here. Having said that, let's add
generic_buffers_fsync/_noflush() implementation in buffer.c with no
inode_lock/unlock() for now so that filesystems like ext2 and
ext4's nojournal mode can use it.

Ext4 when got converted to iomap for direct-io already copied it's own
variant of __generic_file_fsync() without lock.

This patch adds generic_buffers_fsync()
& generic_buffers_fsync_noflush() implementations for use in filesystems
like ext2 & ext4 respectively.

Later we can review other filesystems as well to see if we can make
generic_buffers_fsync/_noflush() which does not take any inode_lock() as
the default path.

Tested-by: default avatarDisha Goel <disgoel@linux.ibm.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarRitesh Harjani (IBM) <ritesh.list@gmail.com>
Signed-off-by: default avatarJan Kara <jack@suse.cz>
Message-Id: <d573408ac8408627d23a3d2d166e748c172c4c9e.1682069716.git.ritesh.list@gmail.com>
parent fcced95b

fs/buffer.c

+70 −0
Original line number Diff line number Diff line
@@ -592,6 +592,76 @@ int sync_mapping_buffers(struct address_space *mapping) 
}

EXPORT_SYMBOL(sync_mapping_buffers);



/**

 * generic_buffers_fsync_noflush - generic buffer fsync implementation

 * for simple filesystems with no inode lock

 *

 * @file:	file to synchronize

 * @start:	start offset in bytes

 * @end:	end offset in bytes (inclusive)

 * @datasync:	only synchronize essential metadata if true

 *

 * This is a generic implementation of the fsync method for simple

 * filesystems which track all non-inode metadata in the buffers list

 * hanging off the address_space structure.

 */

int generic_buffers_fsync_noflush(struct file *file, loff_t start, loff_t end,

				  bool datasync)

{

	struct inode *inode = file->f_mapping->host;

	int err;

	int ret;



	err = file_write_and_wait_range(file, start, end);

	if (err)

		return err;



	ret = sync_mapping_buffers(inode->i_mapping);

	if (!(inode->i_state & I_DIRTY_ALL))

		goto out;

	if (datasync && !(inode->i_state & I_DIRTY_DATASYNC))

		goto out;



	err = sync_inode_metadata(inode, 1);

	if (ret == 0)

		ret = err;



out:

	/* check and advance again to catch errors after syncing out buffers */

	err = file_check_and_advance_wb_err(file);

	if (ret == 0)

		ret = err;

	return ret;

}

EXPORT_SYMBOL(generic_buffers_fsync_noflush);



/**

 * generic_buffers_fsync - generic buffer fsync implementation

 * for simple filesystems with no inode lock

 *

 * @file:	file to synchronize

 * @start:	start offset in bytes

 * @end:	end offset in bytes (inclusive)

 * @datasync:	only synchronize essential metadata if true

 *

 * This is a generic implementation of the fsync method for simple

 * filesystems which track all non-inode metadata in the buffers list

 * hanging off the address_space structure. This also makes sure that

 * a device cache flush operation is called at the end.

 */

int generic_buffers_fsync(struct file *file, loff_t start, loff_t end,

			  bool datasync)

{

	struct inode *inode = file->f_mapping->host;

	int ret;



	ret = generic_buffers_fsync_noflush(file, start, end, datasync);

	if (!ret)

		ret = blkdev_issue_flush(inode->i_sb->s_bdev);

	return ret;

}

EXPORT_SYMBOL(generic_buffers_fsync);



/*

 * Called when we've recently written block `bblock', and it is known that

 * `bblock' was for a buffer_boundary() buffer.  This means that the block at

include/linux/buffer_head.h

+4 −0
Original line number Diff line number Diff line
@@ -217,6 +217,10 @@ int inode_has_buffers(struct inode *); 
void invalidate_inode_buffers(struct inode *);

int remove_inode_buffers(struct inode *inode);

int sync_mapping_buffers(struct address_space *mapping);

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);

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)