zonefs: use iomap for synchronous direct writes

Remove the function zonefs_file_dio_append() that is used to manually
issue REQ_OP_ZONE_APPEND BIOs for processing synchronous direct writes
and use iomap instead.

To preserve the use of zone append operations for synchronous writes,
different struct iomap_dio_ops are defined. For synchronous direct
writes using zone append, zonefs_zone_append_dio_ops is introduced.
The submit_bio operation of this structure is defined as the function
zonefs_file_zone_append_dio_submit_io() which is used to change the BIO
opreation for synchronous direct IO writes to REQ_OP_ZONE_APPEND.

In order to preserve the write location check on completion of zone
append BIOs, the end_io operation is also defined using the function
zonefs_file_zone_append_dio_bio_end_io(). This check now relies on the
zonefs_zone_append_bio structure, allocated together with zone append
BIOs with a dedicated BIO set. This structure include the target inode
of a zone append BIO as well as the target append offset location for
the zone append operation. This is used to perform a check against
bio->bi_iter.bi_sector when the BIO completes, without needing to use
the zone information z_wpoffset field, thus removing the need for
taking the inode truncate mutex.

Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/fs/zonefs/zonefs.h b/fs/zonefs/zonefs.h
index 8175652241b5..f663b8ebc2cb 100644
--- a/fs/zonefs/zonefs.h
+++ b/fs/zonefs/zonefs.h
@@ -279,6 +279,8 @@ extern const struct file_operations zonefs_dir_operations;
 extern const struct address_space_operations zonefs_file_aops;
 extern const struct file_operations zonefs_file_operations;
 int zonefs_file_truncate(struct inode *inode, loff_t isize);
+int zonefs_file_bioset_init(void);
+void zonefs_file_bioset_exit(void);
 
 /* In sysfs.c */
 int zonefs_sysfs_register(struct super_block *sb);