diff mbox series

[4/8] btrfs: Switch to iomap_dio_rw() for dio

Message ID 20191210230155.22688-5-rgoldwyn@suse.de
State New, archived
Headers show
Series btrfs direct-io using iomap | expand

Commit Message

Goldwyn Rodrigues Dec. 10, 2019, 11:01 p.m. UTC
From: Goldwyn Rodrigues <rgoldwyn@suse.com>

Switch from __blockdev_direct_IO() to iomap_dio_rw().
Rename btrfs_get_blocks_direct() to btrfs_dio_iomap_begin() and use it
as iomap_begin() for iomap direct I/O functions. This function
allocates and locks all the blocks required for the I/O.
btrfs_submit_direct() is used as the submit_io() hook for direct I/O
ops.

Since we need direct I/O reads to go through iomap_dio_rw(), we change
file_operations.read_iter() to a btrfs_file_read_iter() which calls
btrfs_direct_IO() for direct reads and falls back to
generic_file_buffered_read() for incomplete reads and buffered reads.

We don't need address_space.direct_IO() anymore so set it to noop.
Similarly, we don't need flags used in __blockdev_direct_IO(). iomap is
capable of direct I/O reads from a hole, so we don't need to return
-ENOENT.

BTRFS direct I/O is now done under i_rwsem, shared in case of
reads and exclusive in case of writes. This guards against simultaneous
truncates.

Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
---
 fs/btrfs/ctree.h |   1 +
 fs/btrfs/file.c  |  21 ++++++-
 fs/btrfs/inode.c | 184 ++++++++++++++++++++++++++-----------------------------
 3 files changed, 107 insertions(+), 99 deletions(-)

Comments

Filipe Manana Dec. 11, 2019, 8:58 a.m. UTC | #1
On Tue, Dec 10, 2019 at 11:02 PM Goldwyn Rodrigues <rgoldwyn@suse.de> wrote:
>
> From: Goldwyn Rodrigues <rgoldwyn@suse.com>
>
> Switch from __blockdev_direct_IO() to iomap_dio_rw().
> Rename btrfs_get_blocks_direct() to btrfs_dio_iomap_begin() and use it
> as iomap_begin() for iomap direct I/O functions. This function
> allocates and locks all the blocks required for the I/O.
> btrfs_submit_direct() is used as the submit_io() hook for direct I/O
> ops.
>
> Since we need direct I/O reads to go through iomap_dio_rw(), we change
> file_operations.read_iter() to a btrfs_file_read_iter() which calls
> btrfs_direct_IO() for direct reads and falls back to
> generic_file_buffered_read() for incomplete reads and buffered reads.
>
> We don't need address_space.direct_IO() anymore so set it to noop.
> Similarly, we don't need flags used in __blockdev_direct_IO(). iomap is
> capable of direct I/O reads from a hole, so we don't need to return
> -ENOENT.
>
> BTRFS direct I/O is now done under i_rwsem, shared in case of
> reads and exclusive in case of writes. This guards against simultaneous
> truncates.
>
> Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
> ---
>  fs/btrfs/ctree.h |   1 +
>  fs/btrfs/file.c  |  21 ++++++-
>  fs/btrfs/inode.c | 184 ++++++++++++++++++++++++++-----------------------------
>  3 files changed, 107 insertions(+), 99 deletions(-)
>
> diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
> index b2e8fd8a8e59..113dcd1a11cd 100644
> --- a/fs/btrfs/ctree.h
> +++ b/fs/btrfs/ctree.h
> @@ -2904,6 +2904,7 @@ int btrfs_writepage_cow_fixup(struct page *page, u64 start, u64 end);
>  void btrfs_writepage_endio_finish_ordered(struct page *page, u64 start,
>                                           u64 end, int uptodate);
>  extern const struct dentry_operations btrfs_dentry_operations;
> +ssize_t btrfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter);
>
>  /* ioctl.c */
>  long btrfs_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
> diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
> index 0cb43b682789..7010dd7beccc 100644
> --- a/fs/btrfs/file.c
> +++ b/fs/btrfs/file.c
> @@ -1832,7 +1832,7 @@ static ssize_t __btrfs_direct_write(struct kiocb *iocb, struct iov_iter *from)
>         loff_t endbyte;
>         int err;
>
> -       written = generic_file_direct_write(iocb, from);
> +       written = btrfs_direct_IO(iocb, from);
>
>         if (written < 0 || !iov_iter_count(from))
>                 return written;
> @@ -3444,9 +3444,26 @@ static int btrfs_file_open(struct inode *inode, struct file *filp)
>         return generic_file_open(inode, filp);
>  }
>
> +static ssize_t btrfs_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
> +{
> +       ssize_t ret = 0;
> +
> +       if (iocb->ki_flags & IOCB_DIRECT) {
> +               struct inode *inode = file_inode(iocb->ki_filp);
> +
> +               inode_lock_shared(inode);
> +               ret = btrfs_direct_IO(iocb, to);
> +               inode_unlock_shared(inode);
> +               if (ret < 0)
> +                       return ret;
> +       }
> +
> +       return generic_file_buffered_read(iocb, to, ret);
> +}
> +
>  const struct file_operations btrfs_file_operations = {
>         .llseek         = btrfs_file_llseek,
> -       .read_iter      = generic_file_read_iter,
> +       .read_iter      = btrfs_file_read_iter,
>         .splice_read    = generic_file_splice_read,
>         .write_iter     = btrfs_file_write_iter,
>         .mmap           = btrfs_file_mmap,
> diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
> index 56032c518b26..86730f2f2bf6 100644
> --- a/fs/btrfs/inode.c
> +++ b/fs/btrfs/inode.c
> @@ -29,6 +29,7 @@
>  #include <linux/iversion.h>
>  #include <linux/swap.h>
>  #include <linux/sched/mm.h>
> +#include <linux/iomap.h>
>  #include <asm/unaligned.h>
>  #include "misc.h"
>  #include "ctree.h"
> @@ -7510,7 +7511,7 @@ noinline int can_nocow_extent(struct inode *inode, u64 offset, u64 *len,
>  }
>
>  static int lock_extent_direct(struct inode *inode, u64 lockstart, u64 lockend,
> -                             struct extent_state **cached_state, int writing)
> +                             struct extent_state **cached_state, bool writing)
>  {
>         struct btrfs_ordered_extent *ordered;
>         int ret = 0;
> @@ -7648,30 +7649,7 @@ static struct extent_map *create_io_em(struct inode *inode, u64 start, u64 len,
>  }
>
>
> -static int btrfs_get_blocks_direct_read(struct extent_map *em,
> -                                       struct buffer_head *bh_result,
> -                                       struct inode *inode,
> -                                       u64 start, u64 len)
> -{
> -       struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
> -
> -       if (em->block_start == EXTENT_MAP_HOLE ||
> -                       test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
> -               return -ENOENT;
> -
> -       len = min(len, em->len - (start - em->start));
> -
> -       bh_result->b_blocknr = (em->block_start + (start - em->start)) >>
> -               inode->i_blkbits;
> -       bh_result->b_size = len;
> -       bh_result->b_bdev = fs_info->fs_devices->latest_bdev;
> -       set_buffer_mapped(bh_result);
> -
> -       return 0;
> -}
> -
>  static int btrfs_get_blocks_direct_write(struct extent_map **map,
> -                                        struct buffer_head *bh_result,
>                                          struct inode *inode,
>                                          struct btrfs_dio_data *dio_data,
>                                          u64 start, u64 len)
> @@ -7733,7 +7711,6 @@ static int btrfs_get_blocks_direct_write(struct extent_map **map,
>         }
>
>         /* this will cow the extent */
> -       len = bh_result->b_size;
>         free_extent_map(em);
>         *map = em = btrfs_new_extent_direct(inode, start, len);
>         if (IS_ERR(em)) {
> @@ -7744,15 +7721,6 @@ static int btrfs_get_blocks_direct_write(struct extent_map **map,
>         len = min(len, em->len - (start - em->start));
>
>  skip_cow:
> -       bh_result->b_blocknr = (em->block_start + (start - em->start)) >>
> -               inode->i_blkbits;
> -       bh_result->b_size = len;
> -       bh_result->b_bdev = fs_info->fs_devices->latest_bdev;
> -       set_buffer_mapped(bh_result);
> -
> -       if (!test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
> -               set_buffer_new(bh_result);
> -
>         /*
>          * Need to update the i_size under the extent lock so buffered
>          * readers will get the updated i_size when we unlock.
> @@ -7768,24 +7736,37 @@ static int btrfs_get_blocks_direct_write(struct extent_map **map,
>         return ret;
>  }
>
> -static int btrfs_get_blocks_direct(struct inode *inode, sector_t iblock,
> -                                  struct buffer_head *bh_result, int create)
> +static int btrfs_dio_iomap_begin(struct inode *inode, loff_t start,
> +               loff_t length, unsigned flags, struct iomap *iomap,
> +               struct iomap *srcmap)
>  {
>         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
>         struct extent_map *em;
>         struct extent_state *cached_state = NULL;
>         struct btrfs_dio_data *dio_data = NULL;
> -       u64 start = iblock << inode->i_blkbits;
>         u64 lockstart, lockend;
> -       u64 len = bh_result->b_size;
> +       bool write = !!(flags & IOMAP_WRITE);
>         int ret = 0;
> +       u64 len = length;
> +       bool unlock_extents = false;
>
> -       if (!create)
> +       if (!write)
>                 len = min_t(u64, len, fs_info->sectorsize);
>
>         lockstart = start;
>         lockend = start + len - 1;
>
> +       /*
> +        * The generic stuff only does filemap_write_and_wait_range, which
> +        * isn't enough if we've written compressed pages to this area, so
> +        * we need to flush the dirty pages again to make absolutely sure
> +        * that any outstanding dirty pages are on disk.
> +        */
> +       if (test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
> +                    &BTRFS_I(inode)->runtime_flags))
> +               ret = filemap_fdatawrite_range(inode->i_mapping, start,
> +                                        start + length - 1);
> +
>         if (current->journal_info) {
>                 /*
>                  * Need to pull our outstanding extents and set journal_info to NULL so
> @@ -7801,7 +7782,7 @@ static int btrfs_get_blocks_direct(struct inode *inode, sector_t iblock,
>          * this range and we need to fallback to buffered.
>          */
>         if (lock_extent_direct(inode, lockstart, lockend, &cached_state,
> -                              create)) {
> +                              write)) {
>                 ret = -ENOTBLK;
>                 goto err;
>         }
> @@ -7833,36 +7814,53 @@ static int btrfs_get_blocks_direct(struct inode *inode, sector_t iblock,
>                 goto unlock_err;
>         }
>
> -       if (create) {
> -               ret = btrfs_get_blocks_direct_write(&em, bh_result, inode,
> +       len = min(len, em->len - (start - em->start));
> +       if (write) {
> +               ret = btrfs_get_blocks_direct_write(&em, inode,
>                                                     dio_data, start, len);
>                 if (ret < 0)
>                         goto unlock_err;
> -
> -               unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart,
> -                                    lockend, &cached_state);
> +               unlock_extents = true;
> +               /* Recalc len in case the new em is smaller than requested */
> +               len = min(len, em->len - (start - em->start));
> +       } else if (em->block_start == EXTENT_MAP_HOLE ||
> +                       test_bit(EXTENT_FLAG_PREALLOC, &em->flags)) {
> +               /* Unlock in case of direct reading from a hole */
> +               unlock_extents = true;
>         } else {
> -               ret = btrfs_get_blocks_direct_read(em, bh_result, inode,
> -                                                  start, len);
> -               /* Can be negative only if we read from a hole */
> -               if (ret < 0) {
> -                       ret = 0;
> -                       free_extent_map(em);
> -                       goto unlock_err;
> -               }
>                 /*
>                  * We need to unlock only the end area that we aren't using.
>                  * The rest is going to be unlocked by the endio routine.
>                  */
> -               lockstart = start + bh_result->b_size;
> -               if (lockstart < lockend) {
> -                       unlock_extent_cached(&BTRFS_I(inode)->io_tree,
> -                                            lockstart, lockend, &cached_state);
> -               } else {
> -                       free_extent_state(cached_state);
> -               }
> +               lockstart = start + len;
> +               if (lockstart < lockend)
> +                       unlock_extents = true;
>         }
>
> +       if (unlock_extents)
> +               unlock_extent_cached(&BTRFS_I(inode)->io_tree,
> +                               lockstart, lockend, &cached_state);
> +       else
> +               free_extent_state(cached_state);
> +
> +       /*
> +        * Translate extent map information to iomap
> +        * We trim the extents (and move the addr) even though
> +        * iomap code does that, since we have locked only the parts
> +        * we are performing I/O in.
> +        */
> +       if ((em->block_start == EXTENT_MAP_HOLE) ||
> +           (test_bit(EXTENT_FLAG_PREALLOC, &em->flags) && !write)) {
> +               iomap->addr = IOMAP_NULL_ADDR;
> +               iomap->type = IOMAP_HOLE;
> +       } else {
> +               iomap->addr = em->block_start + (start - em->start);
> +               iomap->type = IOMAP_MAPPED;
> +       }
> +       iomap->offset = start;
> +       iomap->bdev = fs_info->fs_devices->latest_bdev;
> +       iomap->length = len;
> +
>         free_extent_map(em);
>
>         return 0;
> @@ -8230,9 +8228,8 @@ static void btrfs_endio_direct_read(struct bio *bio)
>         kfree(dip);
>
>         dio_bio->bi_status = err;
> -       dio_end_io(dio_bio);
> +       bio_endio(dio_bio);
>         btrfs_io_bio_free_csum(io_bio);
> -       bio_put(bio);
>  }
>
>  static void __endio_write_update_ordered(struct inode *inode,
> @@ -8289,8 +8286,7 @@ static void btrfs_endio_direct_write(struct bio *bio)
>         kfree(dip);
>
>         dio_bio->bi_status = bio->bi_status;
> -       dio_end_io(dio_bio);
> -       bio_put(bio);
> +       bio_endio(dio_bio);
>  }
>
>  static blk_status_t btrfs_submit_bio_start_direct_io(void *private_data,
> @@ -8522,9 +8518,10 @@ static int btrfs_submit_direct_hook(struct btrfs_dio_private *dip)
>         return 0;
>  }
>
> -static void btrfs_submit_direct(struct bio *dio_bio, struct inode *inode,
> +static blk_qc_t btrfs_submit_direct(struct bio *dio_bio, struct file *file,
>                                 loff_t file_offset)
>  {
> +       struct inode *inode = file_inode(file);
>         struct btrfs_dio_private *dip = NULL;
>         struct bio *bio = NULL;
>         struct btrfs_io_bio *io_bio;
> @@ -8575,7 +8572,7 @@ static void btrfs_submit_direct(struct bio *dio_bio, struct inode *inode,
>
>         ret = btrfs_submit_direct_hook(dip);
>         if (!ret)
> -               return;
> +               return BLK_QC_T_NONE;
>
>         btrfs_io_bio_free_csum(io_bio);
>
> @@ -8594,7 +8591,7 @@ static void btrfs_submit_direct(struct bio *dio_bio, struct inode *inode,
>                 /*
>                  * The end io callbacks free our dip, do the final put on bio
>                  * and all the cleanup and final put for dio_bio (through
> -                * dio_end_io()).
> +                * end_io()).
>                  */
>                 dip = NULL;
>                 bio = NULL;
> @@ -8613,11 +8610,12 @@ static void btrfs_submit_direct(struct bio *dio_bio, struct inode *inode,
>                  * Releases and cleans up our dio_bio, no need to bio_put()
>                  * nor bio_endio()/bio_io_error() against dio_bio.
>                  */
> -               dio_end_io(dio_bio);
> +               bio_endio(dio_bio);

Same as before, the comment is now stale. It mentions no need to call
bio_endio(), yet the change makes it call bio_endio().

thanks

>         }
>         if (bio)
>                 bio_put(bio);
>         kfree(dip);
> +       return BLK_QC_T_NONE;
>  }
>
>  static ssize_t check_direct_IO(struct btrfs_fs_info *fs_info,
> @@ -8653,7 +8651,23 @@ static ssize_t check_direct_IO(struct btrfs_fs_info *fs_info,
>         return retval;
>  }
>
> -static ssize_t btrfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
> +static const struct iomap_ops btrfs_dio_iomap_ops = {
> +       .iomap_begin            = btrfs_dio_iomap_begin,
> +};
> +
> +static const struct iomap_dio_ops btrfs_dops = {
> +       .submit_io              = btrfs_submit_direct,
> +};
> +
> +
> +/*
> + * btrfs_direct_IO - perform direct I/O
> + * inode->i_rwsem must be locked before calling this function, shared or exclusive.
> + * @iocb - kernel iocb
> + * @iter - iter to/from data is copied
> + */
> +
> +ssize_t btrfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
>  {
>         struct file *file = iocb->ki_filp;
>         struct inode *inode = file->f_mapping->host;
> @@ -8662,28 +8676,13 @@ static ssize_t btrfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
>         struct extent_changeset *data_reserved = NULL;
>         loff_t offset = iocb->ki_pos;
>         size_t count = 0;
> -       int flags = 0;
> -       bool wakeup = true;
>         bool relock = false;
>         ssize_t ret;
>
>         if (check_direct_IO(fs_info, iter, offset))
>                 return 0;
>
> -       inode_dio_begin(inode);
> -
> -       /*
> -        * The generic stuff only does filemap_write_and_wait_range, which
> -        * isn't enough if we've written compressed pages to this area, so
> -        * we need to flush the dirty pages again to make absolutely sure
> -        * that any outstanding dirty pages are on disk.
> -        */
>         count = iov_iter_count(iter);
> -       if (test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
> -                    &BTRFS_I(inode)->runtime_flags))
> -               filemap_fdatawrite_range(inode->i_mapping, offset,
> -                                        offset + count - 1);
> -
>         if (iov_iter_rw(iter) == WRITE) {
>                 /*
>                  * If the write DIO is beyond the EOF, we need update
> @@ -8714,17 +8713,11 @@ static ssize_t btrfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
>                 dio_data.unsubmitted_oe_range_end = (u64)offset;
>                 current->journal_info = &dio_data;
>                 down_read(&BTRFS_I(inode)->dio_sem);
> -       } else if (test_bit(BTRFS_INODE_READDIO_NEED_LOCK,
> -                                    &BTRFS_I(inode)->runtime_flags)) {
> -               inode_dio_end(inode);
> -               flags = DIO_LOCKING | DIO_SKIP_HOLES;
> -               wakeup = false;
>         }
>
> -       ret = __blockdev_direct_IO(iocb, inode,
> -                                  fs_info->fs_devices->latest_bdev,
> -                                  iter, btrfs_get_blocks_direct, NULL,
> -                                  btrfs_submit_direct, flags);
> +       ret = iomap_dio_rw(iocb, iter, &btrfs_dio_iomap_ops, &btrfs_dops,
> +                       is_sync_kiocb(iocb));
> +
>         if (iov_iter_rw(iter) == WRITE) {
>                 up_read(&BTRFS_I(inode)->dio_sem);
>                 current->journal_info = NULL;
> @@ -8751,11 +8744,8 @@ static ssize_t btrfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
>                 btrfs_delalloc_release_extents(BTRFS_I(inode), count);
>         }
>  out:
> -       if (wakeup)
> -               inode_dio_end(inode);
>         if (relock)
>                 inode_lock(inode);
> -
>         extent_changeset_free(data_reserved);
>         return ret;
>  }
> @@ -11045,7 +11035,7 @@ static const struct address_space_operations btrfs_aops = {
>         .writepage      = btrfs_writepage,
>         .writepages     = btrfs_writepages,
>         .readpages      = btrfs_readpages,
> -       .direct_IO      = btrfs_direct_IO,
> +       .direct_IO      = noop_direct_IO,
>         .invalidatepage = btrfs_invalidatepage,
>         .releasepage    = btrfs_releasepage,
>         .set_page_dirty = btrfs_set_page_dirty,
> --
> 2.16.4
>
Nikolay Borisov Dec. 11, 2019, 10:43 a.m. UTC | #2
On 11.12.19 г. 1:01 ч., Goldwyn Rodrigues wrote:
> From: Goldwyn Rodrigues <rgoldwyn@suse.com>
> 
> Switch from __blockdev_direct_IO() to iomap_dio_rw().
> Rename btrfs_get_blocks_direct() to btrfs_dio_iomap_begin() and use it
> as iomap_begin() for iomap direct I/O functions. This function
> allocates and locks all the blocks required for the I/O.
> btrfs_submit_direct() is used as the submit_io() hook for direct I/O
> ops.
> 
> Since we need direct I/O reads to go through iomap_dio_rw(), we change
> file_operations.read_iter() to a btrfs_file_read_iter() which calls
> btrfs_direct_IO() for direct reads and falls back to
> generic_file_buffered_read() for incomplete reads and buffered reads.
> 
> We don't need address_space.direct_IO() anymore so set it to noop.
> Similarly, we don't need flags used in __blockdev_direct_IO(). iomap is
> capable of direct I/O reads from a hole, so we don't need to return
> -ENOENT.
> 
> BTRFS direct I/O is now done under i_rwsem, shared in case of
> reads and exclusive in case of writes. This guards against simultaneous
> truncates.
> 
> Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
> ---
>  fs/btrfs/ctree.h |   1 +
>  fs/btrfs/file.c  |  21 ++++++-
>  fs/btrfs/inode.c | 184 ++++++++++++++++++++++++++-----------------------------
>  3 files changed, 107 insertions(+), 99 deletions(-)
> 

<snip>

> +
> +/*
> + * btrfs_direct_IO - perform direct I/O
> + * inode->i_rwsem must be locked before calling this function, shared or exclusive.

Instead of having this as a comment which cannot easily be checked
automatically I'd rather it gets codified via lockdep_assert_held. I
believe this is in line with Dave's comment comment on patch 3.

> + * @iocb - kernel iocb
> + * @iter - iter to/from data is copied
> + */
> +
> +ssize_t btrfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
>  {
>  	struct file *file = iocb->ki_filp;
>  	struct inode *inode = file->f_mapping->host;
> @@ -8662,28 +8676,13 @@ static ssize_t btrfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
>  	struct extent_changeset *data_reserved = NULL;
>  	loff_t offset = iocb->ki_pos;
>  	size_t count = 0;
> -	int flags = 0;
> -	bool wakeup = true;
>  	bool relock = false;
>  	ssize_t ret;
>  
>  	if (check_direct_IO(fs_info, iter, offset))
>  		return 0;
>  
> -	inode_dio_begin(inode);
> -
> -	/*
> -	 * The generic stuff only does filemap_write_and_wait_range, which
> -	 * isn't enough if we've written compressed pages to this area, so
> -	 * we need to flush the dirty pages again to make absolutely sure
> -	 * that any outstanding dirty pages are on disk.
> -	 */
>  	count = iov_iter_count(iter);
> -	if (test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
> -		     &BTRFS_I(inode)->runtime_flags))
> -		filemap_fdatawrite_range(inode->i_mapping, offset,
> -					 offset + count - 1);
> -
>  	if (iov_iter_rw(iter) == WRITE) {
>  		/*
>  		 * If the write DIO is beyond the EOF, we need update
> @@ -8714,17 +8713,11 @@ static ssize_t btrfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
>  		dio_data.unsubmitted_oe_range_end = (u64)offset;
>  		current->journal_info = &dio_data;
>  		down_read(&BTRFS_I(inode)->dio_sem);
> -	} else if (test_bit(BTRFS_INODE_READDIO_NEED_LOCK,
> -				     &BTRFS_I(inode)->runtime_flags)) {
> -		inode_dio_end(inode);
> -		flags = DIO_LOCKING | DIO_SKIP_HOLES;
> -		wakeup = false;
>  	}
>  
> -	ret = __blockdev_direct_IO(iocb, inode,
> -				   fs_info->fs_devices->latest_bdev,
> -				   iter, btrfs_get_blocks_direct, NULL,
> -				   btrfs_submit_direct, flags);
> +	ret = iomap_dio_rw(iocb, iter, &btrfs_dio_iomap_ops, &btrfs_dops,
> +			is_sync_kiocb(iocb));
> +
>  	if (iov_iter_rw(iter) == WRITE) {
>  		up_read(&BTRFS_I(inode)->dio_sem);
>  		current->journal_info = NULL;
> @@ -8751,11 +8744,8 @@ static ssize_t btrfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
>  		btrfs_delalloc_release_extents(BTRFS_I(inode), count);
>  	}
>  out:
> -	if (wakeup)
> -		inode_dio_end(inode);
>  	if (relock)
>  		inode_lock(inode);
> -
>  	extent_changeset_free(data_reserved);
>  	return ret;
>  }
> @@ -11045,7 +11035,7 @@ static const struct address_space_operations btrfs_aops = {
>  	.writepage	= btrfs_writepage,
>  	.writepages	= btrfs_writepages,
>  	.readpages	= btrfs_readpages,
> -	.direct_IO	= btrfs_direct_IO,
> +	.direct_IO	= noop_direct_IO,
>  	.invalidatepage = btrfs_invalidatepage,
>  	.releasepage	= btrfs_releasepage,
>  	.set_page_dirty	= btrfs_set_page_dirty,
>
diff mbox series

Patch

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index b2e8fd8a8e59..113dcd1a11cd 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -2904,6 +2904,7 @@  int btrfs_writepage_cow_fixup(struct page *page, u64 start, u64 end);
 void btrfs_writepage_endio_finish_ordered(struct page *page, u64 start,
 					  u64 end, int uptodate);
 extern const struct dentry_operations btrfs_dentry_operations;
+ssize_t btrfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter);
 
 /* ioctl.c */
 long btrfs_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 0cb43b682789..7010dd7beccc 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -1832,7 +1832,7 @@  static ssize_t __btrfs_direct_write(struct kiocb *iocb, struct iov_iter *from)
 	loff_t endbyte;
 	int err;
 
-	written = generic_file_direct_write(iocb, from);
+	written = btrfs_direct_IO(iocb, from);
 
 	if (written < 0 || !iov_iter_count(from))
 		return written;
@@ -3444,9 +3444,26 @@  static int btrfs_file_open(struct inode *inode, struct file *filp)
 	return generic_file_open(inode, filp);
 }
 
+static ssize_t btrfs_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
+{
+	ssize_t ret = 0;
+
+	if (iocb->ki_flags & IOCB_DIRECT) {
+		struct inode *inode = file_inode(iocb->ki_filp);
+
+		inode_lock_shared(inode);
+		ret = btrfs_direct_IO(iocb, to);
+		inode_unlock_shared(inode);
+		if (ret < 0)
+			return ret;
+	}
+
+	return generic_file_buffered_read(iocb, to, ret);
+}
+
 const struct file_operations btrfs_file_operations = {
 	.llseek		= btrfs_file_llseek,
-	.read_iter      = generic_file_read_iter,
+	.read_iter      = btrfs_file_read_iter,
 	.splice_read	= generic_file_splice_read,
 	.write_iter	= btrfs_file_write_iter,
 	.mmap		= btrfs_file_mmap,
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 56032c518b26..86730f2f2bf6 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -29,6 +29,7 @@ 
 #include <linux/iversion.h>
 #include <linux/swap.h>
 #include <linux/sched/mm.h>
+#include <linux/iomap.h>
 #include <asm/unaligned.h>
 #include "misc.h"
 #include "ctree.h"
@@ -7510,7 +7511,7 @@  noinline int can_nocow_extent(struct inode *inode, u64 offset, u64 *len,
 }
 
 static int lock_extent_direct(struct inode *inode, u64 lockstart, u64 lockend,
-			      struct extent_state **cached_state, int writing)
+			      struct extent_state **cached_state, bool writing)
 {
 	struct btrfs_ordered_extent *ordered;
 	int ret = 0;
@@ -7648,30 +7649,7 @@  static struct extent_map *create_io_em(struct inode *inode, u64 start, u64 len,
 }
 
 
-static int btrfs_get_blocks_direct_read(struct extent_map *em,
-					struct buffer_head *bh_result,
-					struct inode *inode,
-					u64 start, u64 len)
-{
-	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
-
-	if (em->block_start == EXTENT_MAP_HOLE ||
-			test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
-		return -ENOENT;
-
-	len = min(len, em->len - (start - em->start));
-
-	bh_result->b_blocknr = (em->block_start + (start - em->start)) >>
-		inode->i_blkbits;
-	bh_result->b_size = len;
-	bh_result->b_bdev = fs_info->fs_devices->latest_bdev;
-	set_buffer_mapped(bh_result);
-
-	return 0;
-}
-
 static int btrfs_get_blocks_direct_write(struct extent_map **map,
-					 struct buffer_head *bh_result,
 					 struct inode *inode,
 					 struct btrfs_dio_data *dio_data,
 					 u64 start, u64 len)
@@ -7733,7 +7711,6 @@  static int btrfs_get_blocks_direct_write(struct extent_map **map,
 	}
 
 	/* this will cow the extent */
-	len = bh_result->b_size;
 	free_extent_map(em);
 	*map = em = btrfs_new_extent_direct(inode, start, len);
 	if (IS_ERR(em)) {
@@ -7744,15 +7721,6 @@  static int btrfs_get_blocks_direct_write(struct extent_map **map,
 	len = min(len, em->len - (start - em->start));
 
 skip_cow:
-	bh_result->b_blocknr = (em->block_start + (start - em->start)) >>
-		inode->i_blkbits;
-	bh_result->b_size = len;
-	bh_result->b_bdev = fs_info->fs_devices->latest_bdev;
-	set_buffer_mapped(bh_result);
-
-	if (!test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
-		set_buffer_new(bh_result);
-
 	/*
 	 * Need to update the i_size under the extent lock so buffered
 	 * readers will get the updated i_size when we unlock.
@@ -7768,24 +7736,37 @@  static int btrfs_get_blocks_direct_write(struct extent_map **map,
 	return ret;
 }
 
-static int btrfs_get_blocks_direct(struct inode *inode, sector_t iblock,
-				   struct buffer_head *bh_result, int create)
+static int btrfs_dio_iomap_begin(struct inode *inode, loff_t start,
+		loff_t length, unsigned flags, struct iomap *iomap,
+		struct iomap *srcmap)
 {
 	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
 	struct extent_map *em;
 	struct extent_state *cached_state = NULL;
 	struct btrfs_dio_data *dio_data = NULL;
-	u64 start = iblock << inode->i_blkbits;
 	u64 lockstart, lockend;
-	u64 len = bh_result->b_size;
+	bool write = !!(flags & IOMAP_WRITE);
 	int ret = 0;
+	u64 len = length;
+	bool unlock_extents = false;
 
-	if (!create)
+	if (!write)
 		len = min_t(u64, len, fs_info->sectorsize);
 
 	lockstart = start;
 	lockend = start + len - 1;
 
+	/*
+	 * The generic stuff only does filemap_write_and_wait_range, which
+	 * isn't enough if we've written compressed pages to this area, so
+	 * we need to flush the dirty pages again to make absolutely sure
+	 * that any outstanding dirty pages are on disk.
+	 */
+	if (test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
+		     &BTRFS_I(inode)->runtime_flags))
+		ret = filemap_fdatawrite_range(inode->i_mapping, start,
+					 start + length - 1);
+
 	if (current->journal_info) {
 		/*
 		 * Need to pull our outstanding extents and set journal_info to NULL so
@@ -7801,7 +7782,7 @@  static int btrfs_get_blocks_direct(struct inode *inode, sector_t iblock,
 	 * this range and we need to fallback to buffered.
 	 */
 	if (lock_extent_direct(inode, lockstart, lockend, &cached_state,
-			       create)) {
+			       write)) {
 		ret = -ENOTBLK;
 		goto err;
 	}
@@ -7833,36 +7814,53 @@  static int btrfs_get_blocks_direct(struct inode *inode, sector_t iblock,
 		goto unlock_err;
 	}
 
-	if (create) {
-		ret = btrfs_get_blocks_direct_write(&em, bh_result, inode,
+	len = min(len, em->len - (start - em->start));
+	if (write) {
+		ret = btrfs_get_blocks_direct_write(&em, inode,
 						    dio_data, start, len);
 		if (ret < 0)
 			goto unlock_err;
-
-		unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart,
-				     lockend, &cached_state);
+		unlock_extents = true;
+		/* Recalc len in case the new em is smaller than requested */
+		len = min(len, em->len - (start - em->start));
+	} else if (em->block_start == EXTENT_MAP_HOLE ||
+			test_bit(EXTENT_FLAG_PREALLOC, &em->flags)) {
+		/* Unlock in case of direct reading from a hole */
+		unlock_extents = true;
 	} else {
-		ret = btrfs_get_blocks_direct_read(em, bh_result, inode,
-						   start, len);
-		/* Can be negative only if we read from a hole */
-		if (ret < 0) {
-			ret = 0;
-			free_extent_map(em);
-			goto unlock_err;
-		}
 		/*
 		 * We need to unlock only the end area that we aren't using.
 		 * The rest is going to be unlocked by the endio routine.
 		 */
-		lockstart = start + bh_result->b_size;
-		if (lockstart < lockend) {
-			unlock_extent_cached(&BTRFS_I(inode)->io_tree,
-					     lockstart, lockend, &cached_state);
-		} else {
-			free_extent_state(cached_state);
-		}
+		lockstart = start + len;
+		if (lockstart < lockend)
+			unlock_extents = true;
 	}
 
+	if (unlock_extents)
+		unlock_extent_cached(&BTRFS_I(inode)->io_tree,
+				lockstart, lockend, &cached_state);
+	else
+		free_extent_state(cached_state);
+
+	/*
+	 * Translate extent map information to iomap
+	 * We trim the extents (and move the addr) even though
+	 * iomap code does that, since we have locked only the parts
+	 * we are performing I/O in.
+	 */
+	if ((em->block_start == EXTENT_MAP_HOLE) ||
+	    (test_bit(EXTENT_FLAG_PREALLOC, &em->flags) && !write)) {
+		iomap->addr = IOMAP_NULL_ADDR;
+		iomap->type = IOMAP_HOLE;
+	} else {
+		iomap->addr = em->block_start + (start - em->start);
+		iomap->type = IOMAP_MAPPED;
+	}
+	iomap->offset = start;
+	iomap->bdev = fs_info->fs_devices->latest_bdev;
+	iomap->length = len;
+
 	free_extent_map(em);
 
 	return 0;
@@ -8230,9 +8228,8 @@  static void btrfs_endio_direct_read(struct bio *bio)
 	kfree(dip);
 
 	dio_bio->bi_status = err;
-	dio_end_io(dio_bio);
+	bio_endio(dio_bio);
 	btrfs_io_bio_free_csum(io_bio);
-	bio_put(bio);
 }
 
 static void __endio_write_update_ordered(struct inode *inode,
@@ -8289,8 +8286,7 @@  static void btrfs_endio_direct_write(struct bio *bio)
 	kfree(dip);
 
 	dio_bio->bi_status = bio->bi_status;
-	dio_end_io(dio_bio);
-	bio_put(bio);
+	bio_endio(dio_bio);
 }
 
 static blk_status_t btrfs_submit_bio_start_direct_io(void *private_data,
@@ -8522,9 +8518,10 @@  static int btrfs_submit_direct_hook(struct btrfs_dio_private *dip)
 	return 0;
 }
 
-static void btrfs_submit_direct(struct bio *dio_bio, struct inode *inode,
+static blk_qc_t btrfs_submit_direct(struct bio *dio_bio, struct file *file,
 				loff_t file_offset)
 {
+	struct inode *inode = file_inode(file);
 	struct btrfs_dio_private *dip = NULL;
 	struct bio *bio = NULL;
 	struct btrfs_io_bio *io_bio;
@@ -8575,7 +8572,7 @@  static void btrfs_submit_direct(struct bio *dio_bio, struct inode *inode,
 
 	ret = btrfs_submit_direct_hook(dip);
 	if (!ret)
-		return;
+		return BLK_QC_T_NONE;
 
 	btrfs_io_bio_free_csum(io_bio);
 
@@ -8594,7 +8591,7 @@  static void btrfs_submit_direct(struct bio *dio_bio, struct inode *inode,
 		/*
 		 * The end io callbacks free our dip, do the final put on bio
 		 * and all the cleanup and final put for dio_bio (through
-		 * dio_end_io()).
+		 * end_io()).
 		 */
 		dip = NULL;
 		bio = NULL;
@@ -8613,11 +8610,12 @@  static void btrfs_submit_direct(struct bio *dio_bio, struct inode *inode,
 		 * Releases and cleans up our dio_bio, no need to bio_put()
 		 * nor bio_endio()/bio_io_error() against dio_bio.
 		 */
-		dio_end_io(dio_bio);
+		bio_endio(dio_bio);
 	}
 	if (bio)
 		bio_put(bio);
 	kfree(dip);
+	return BLK_QC_T_NONE;
 }
 
 static ssize_t check_direct_IO(struct btrfs_fs_info *fs_info,
@@ -8653,7 +8651,23 @@  static ssize_t check_direct_IO(struct btrfs_fs_info *fs_info,
 	return retval;
 }
 
-static ssize_t btrfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
+static const struct iomap_ops btrfs_dio_iomap_ops = {
+	.iomap_begin            = btrfs_dio_iomap_begin,
+};
+
+static const struct iomap_dio_ops btrfs_dops = {
+	.submit_io		= btrfs_submit_direct,
+};
+
+
+/*
+ * btrfs_direct_IO - perform direct I/O
+ * inode->i_rwsem must be locked before calling this function, shared or exclusive.
+ * @iocb - kernel iocb
+ * @iter - iter to/from data is copied
+ */
+
+ssize_t btrfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 {
 	struct file *file = iocb->ki_filp;
 	struct inode *inode = file->f_mapping->host;
@@ -8662,28 +8676,13 @@  static ssize_t btrfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 	struct extent_changeset *data_reserved = NULL;
 	loff_t offset = iocb->ki_pos;
 	size_t count = 0;
-	int flags = 0;
-	bool wakeup = true;
 	bool relock = false;
 	ssize_t ret;
 
 	if (check_direct_IO(fs_info, iter, offset))
 		return 0;
 
-	inode_dio_begin(inode);
-
-	/*
-	 * The generic stuff only does filemap_write_and_wait_range, which
-	 * isn't enough if we've written compressed pages to this area, so
-	 * we need to flush the dirty pages again to make absolutely sure
-	 * that any outstanding dirty pages are on disk.
-	 */
 	count = iov_iter_count(iter);
-	if (test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
-		     &BTRFS_I(inode)->runtime_flags))
-		filemap_fdatawrite_range(inode->i_mapping, offset,
-					 offset + count - 1);
-
 	if (iov_iter_rw(iter) == WRITE) {
 		/*
 		 * If the write DIO is beyond the EOF, we need update
@@ -8714,17 +8713,11 @@  static ssize_t btrfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 		dio_data.unsubmitted_oe_range_end = (u64)offset;
 		current->journal_info = &dio_data;
 		down_read(&BTRFS_I(inode)->dio_sem);
-	} else if (test_bit(BTRFS_INODE_READDIO_NEED_LOCK,
-				     &BTRFS_I(inode)->runtime_flags)) {
-		inode_dio_end(inode);
-		flags = DIO_LOCKING | DIO_SKIP_HOLES;
-		wakeup = false;
 	}
 
-	ret = __blockdev_direct_IO(iocb, inode,
-				   fs_info->fs_devices->latest_bdev,
-				   iter, btrfs_get_blocks_direct, NULL,
-				   btrfs_submit_direct, flags);
+	ret = iomap_dio_rw(iocb, iter, &btrfs_dio_iomap_ops, &btrfs_dops,
+			is_sync_kiocb(iocb));
+
 	if (iov_iter_rw(iter) == WRITE) {
 		up_read(&BTRFS_I(inode)->dio_sem);
 		current->journal_info = NULL;
@@ -8751,11 +8744,8 @@  static ssize_t btrfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 		btrfs_delalloc_release_extents(BTRFS_I(inode), count);
 	}
 out:
-	if (wakeup)
-		inode_dio_end(inode);
 	if (relock)
 		inode_lock(inode);
-
 	extent_changeset_free(data_reserved);
 	return ret;
 }
@@ -11045,7 +11035,7 @@  static const struct address_space_operations btrfs_aops = {
 	.writepage	= btrfs_writepage,
 	.writepages	= btrfs_writepages,
 	.readpages	= btrfs_readpages,
-	.direct_IO	= btrfs_direct_IO,
+	.direct_IO	= noop_direct_IO,
 	.invalidatepage = btrfs_invalidatepage,
 	.releasepage	= btrfs_releasepage,
 	.set_page_dirty	= btrfs_set_page_dirty,