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zonefs: use iomap for synchronous direct writes
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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>
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Damien Le Moal committed Jun 13, 2023
1 parent 9561de3 commit 16d7fd3
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Showing 3 changed files with 120 additions and 97 deletions.
206 changes: 110 additions & 96 deletions fs/zonefs/file.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -342,6 +342,77 @@ static loff_t zonefs_file_llseek(struct file *file, loff_t offset, int whence)
return generic_file_llseek_size(file, offset, whence, isize, isize);
}

struct zonefs_zone_append_bio {
/* The target inode of the BIO */
struct inode *inode;

/* For sync writes, the target append write offset */
u64 append_offset;

/*
* This member must come last, bio_alloc_bioset will allocate enough
* bytes for entire zonefs_bio but relies on bio being last.
*/
struct bio bio;
};

static inline struct zonefs_zone_append_bio *
zonefs_zone_append_bio(struct bio *bio)
{
return container_of(bio, struct zonefs_zone_append_bio, bio);
}

static void zonefs_file_zone_append_dio_bio_end_io(struct bio *bio)
{
struct zonefs_zone_append_bio *za_bio = zonefs_zone_append_bio(bio);
struct zonefs_zone *z = zonefs_inode_zone(za_bio->inode);
sector_t za_sector;

if (bio->bi_status != BLK_STS_OK)
goto bio_end;

/*
* If the file zone was written underneath the file system, the zone
* append operation can still succedd (if the zone is not full) but
* the write append location will not be where we expect it to be.
* Check that we wrote where we intended to, that is, at z->z_wpoffset.
*/
za_sector = z->z_sector + (za_bio->append_offset >> SECTOR_SHIFT);
if (bio->bi_iter.bi_sector != za_sector) {
zonefs_warn(za_bio->inode->i_sb,
"Invalid write sector %llu for zone at %llu\n",
bio->bi_iter.bi_sector, z->z_sector);
bio->bi_status = BLK_STS_IOERR;
}

bio_end:
iomap_dio_bio_end_io(bio);
}

static void zonefs_file_zone_append_dio_submit_io(const struct iomap_iter *iter,
struct bio *bio,
loff_t file_offset)
{
struct zonefs_zone_append_bio *za_bio = zonefs_zone_append_bio(bio);
struct inode *inode = iter->inode;
struct zonefs_zone *z = zonefs_inode_zone(inode);

/*
* Issue a zone append BIO to process sync dio writes. The append
* file offset is saved to check the zone append write location
* on completion of the BIO.
*/
za_bio->inode = inode;
za_bio->append_offset = file_offset;

bio->bi_opf &= ~REQ_OP_WRITE;
bio->bi_opf |= REQ_OP_ZONE_APPEND;
bio->bi_iter.bi_sector = z->z_sector;
bio->bi_end_io = zonefs_file_zone_append_dio_bio_end_io;

submit_bio(bio);
}

static int zonefs_file_write_dio_end_io(struct kiocb *iocb, ssize_t size,
int error, unsigned int flags)
{
Expand Down Expand Up @@ -372,93 +443,17 @@ static int zonefs_file_write_dio_end_io(struct kiocb *iocb, ssize_t size,
return 0;
}

static const struct iomap_dio_ops zonefs_write_dio_ops = {
.end_io = zonefs_file_write_dio_end_io,
};
static struct bio_set zonefs_zone_append_bio_set;

static ssize_t zonefs_file_dio_append(struct kiocb *iocb, struct iov_iter *from)
{
struct inode *inode = file_inode(iocb->ki_filp);
struct zonefs_zone *z = zonefs_inode_zone(inode);
struct block_device *bdev = inode->i_sb->s_bdev;
unsigned int max = bdev_max_zone_append_sectors(bdev);
pgoff_t start, end;
struct bio *bio;
ssize_t size = 0;
int nr_pages;
ssize_t ret;

max = ALIGN_DOWN(max << SECTOR_SHIFT, inode->i_sb->s_blocksize);
iov_iter_truncate(from, max);

/*
* If the inode block size (zone write granularity) is smaller than the
* page size, we may be appending data belonging to the last page of the
* inode straddling inode->i_size, with that page already cached due to
* a buffered read or readahead. So make sure to invalidate that page.
* This will always be a no-op for the case where the block size is
* equal to the page size.
*/
start = iocb->ki_pos >> PAGE_SHIFT;
end = (iocb->ki_pos + iov_iter_count(from) - 1) >> PAGE_SHIFT;
if (invalidate_inode_pages2_range(inode->i_mapping, start, end))
return -EBUSY;

nr_pages = iov_iter_npages(from, BIO_MAX_VECS);
if (!nr_pages)
return 0;

bio = bio_alloc(bdev, nr_pages,
REQ_OP_ZONE_APPEND | REQ_SYNC | REQ_IDLE, GFP_NOFS);
bio->bi_iter.bi_sector = z->z_sector;
bio->bi_ioprio = iocb->ki_ioprio;
if (iocb_is_dsync(iocb))
bio->bi_opf |= REQ_FUA;

ret = bio_iov_iter_get_pages(bio, from);
if (unlikely(ret))
goto out_release;

size = bio->bi_iter.bi_size;
task_io_account_write(size);

if (iocb->ki_flags & IOCB_HIPRI)
bio_set_polled(bio, iocb);

ret = submit_bio_wait(bio);

/*
* If the file zone was written underneath the file system, the zone
* write pointer may not be where we expect it to be, but the zone
* append write can still succeed. So check manually that we wrote where
* we intended to, that is, at zi->i_wpoffset.
*/
if (!ret) {
sector_t wpsector =
z->z_sector + (z->z_wpoffset >> SECTOR_SHIFT);

if (bio->bi_iter.bi_sector != wpsector) {
zonefs_warn(inode->i_sb,
"Corrupted write pointer %llu for zone at %llu\n",
bio->bi_iter.bi_sector, z->z_sector);
ret = -EIO;
}
}

zonefs_file_write_dio_end_io(iocb, size, ret, 0);
trace_zonefs_file_dio_append(inode, size, ret);

out_release:
bio_release_pages(bio, false);
bio_put(bio);

if (ret >= 0) {
iocb->ki_pos += size;
return size;
}
static const struct iomap_dio_ops zonefs_zone_append_dio_ops = {
.submit_io = zonefs_file_zone_append_dio_submit_io,
.end_io = zonefs_file_write_dio_end_io,
.bio_set = &zonefs_zone_append_bio_set,
};

return ret;
}
static const struct iomap_dio_ops zonefs_write_dio_ops = {
.end_io = zonefs_file_write_dio_end_io,
};

/*
* Do not exceed the LFS limits nor the file zone size. If pos is under the
Expand Down Expand Up @@ -539,6 +534,7 @@ static ssize_t zonefs_file_dio_write(struct kiocb *iocb, struct iov_iter *from)
struct zonefs_inode_info *zi = ZONEFS_I(inode);
struct zonefs_zone *z = zonefs_inode_zone(inode);
struct super_block *sb = inode->i_sb;
const struct iomap_dio_ops *dio_ops;
bool sync = is_sync_kiocb(iocb);
bool append = false;
ssize_t ret, count;
Expand Down Expand Up @@ -582,20 +578,26 @@ static ssize_t zonefs_file_dio_write(struct kiocb *iocb, struct iov_iter *from)
}

if (append) {
ret = zonefs_file_dio_append(iocb, from);
unsigned int max = bdev_max_zone_append_sectors(sb->s_bdev);

max = ALIGN_DOWN(max << SECTOR_SHIFT, sb->s_blocksize);
iov_iter_truncate(from, max);

dio_ops = &zonefs_zone_append_dio_ops;
} else {
/*
* iomap_dio_rw() may return ENOTBLK if there was an issue with
* page invalidation. Overwrite that error code with EBUSY to
* be consistent with zonefs_file_dio_append() return value for
* similar issues.
*/
ret = iomap_dio_rw(iocb, from, &zonefs_write_iomap_ops,
&zonefs_write_dio_ops, 0, NULL, 0);
if (ret == -ENOTBLK)
ret = -EBUSY;
dio_ops = &zonefs_write_dio_ops;
}

/*
* iomap_dio_rw() may return ENOTBLK if there was an issue with
* page invalidation. Overwrite that error code with EBUSY so that
* the user can make sense of the error.
*/
ret = iomap_dio_rw(iocb, from, &zonefs_write_iomap_ops,
dio_ops, 0, NULL, 0);
if (ret == -ENOTBLK)
ret = -EBUSY;

if (zonefs_zone_is_seq(z) &&
(ret > 0 || ret == -EIOCBQUEUED)) {
if (ret > 0)
Expand Down Expand Up @@ -900,3 +902,15 @@ const struct file_operations zonefs_file_operations = {
.splice_write = iter_file_splice_write,
.iopoll = iocb_bio_iopoll,
};

int zonefs_file_bioset_init(void)
{
return bioset_init(&zonefs_zone_append_bio_set, BIO_POOL_SIZE,
offsetof(struct zonefs_zone_append_bio, bio),
BIOSET_NEED_BVECS);
}

void zonefs_file_bioset_exit(void)
{
bioset_exit(&zonefs_zone_append_bio_set);
}
9 changes: 8 additions & 1 deletion fs/zonefs/super.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1412,10 +1412,14 @@ static int __init zonefs_init(void)

BUILD_BUG_ON(sizeof(struct zonefs_super) != ZONEFS_SUPER_SIZE);

ret = zonefs_init_inodecache();
ret = zonefs_file_bioset_init();
if (ret)
return ret;

ret = zonefs_init_inodecache();
if (ret)
goto destroy_bioset;

ret = zonefs_sysfs_init();
if (ret)
goto destroy_inodecache;
Expand All @@ -1430,6 +1434,8 @@ static int __init zonefs_init(void)
zonefs_sysfs_exit();
destroy_inodecache:
zonefs_destroy_inodecache();
destroy_bioset:
zonefs_file_bioset_exit();

return ret;
}
Expand All @@ -1439,6 +1445,7 @@ static void __exit zonefs_exit(void)
unregister_filesystem(&zonefs_type);
zonefs_sysfs_exit();
zonefs_destroy_inodecache();
zonefs_file_bioset_exit();
}

MODULE_AUTHOR("Damien Le Moal");
Expand Down
2 changes: 2 additions & 0 deletions fs/zonefs/zonefs.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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);
Expand Down

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