gfs2: iomap direct I/O support
The page unmapping previously done in gfs2_direct_IO is now done generically in iomap_dio_rw. Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com> Reviewed-by: Bob Peterson <rpeterso@redhat.com>
This commit is contained in:
Andreas Gruenbacher
parent
bcfe94139a
commit
967bcc91b0
100
fs/gfs2/aops.c
100
fs/gfs2/aops.c
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@ -84,12 +84,6 @@ static int gfs2_get_block_noalloc(struct inode *inode, sector_t lblock,
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return 0;
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}
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static int gfs2_get_block_direct(struct inode *inode, sector_t lblock,
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struct buffer_head *bh_result, int create)
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{
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return gfs2_block_map(inode, lblock, bh_result, 0);
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}
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/**
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* gfs2_writepage_common - Common bits of writepage
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* @page: The page to be written
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@ -1024,96 +1018,6 @@ static void gfs2_invalidatepage(struct page *page, unsigned int offset,
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try_to_release_page(page, 0);
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}
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/**
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* gfs2_ok_for_dio - check that dio is valid on this file
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* @ip: The inode
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* @offset: The offset at which we are reading or writing
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*
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* Returns: 0 (to ignore the i/o request and thus fall back to buffered i/o)
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* 1 (to accept the i/o request)
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*/
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static int gfs2_ok_for_dio(struct gfs2_inode *ip, loff_t offset)
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{
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/*
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* Should we return an error here? I can't see that O_DIRECT for
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* a stuffed file makes any sense. For now we'll silently fall
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* back to buffered I/O
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*/
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if (gfs2_is_stuffed(ip))
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return 0;
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if (offset >= i_size_read(&ip->i_inode))
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return 0;
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return 1;
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}
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static ssize_t gfs2_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
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{
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struct file *file = iocb->ki_filp;
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struct inode *inode = file->f_mapping->host;
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struct address_space *mapping = inode->i_mapping;
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struct gfs2_inode *ip = GFS2_I(inode);
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loff_t offset = iocb->ki_pos;
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struct gfs2_holder gh;
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int rv;
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/*
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* Deferred lock, even if its a write, since we do no allocation
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* on this path. All we need change is atime, and this lock mode
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* ensures that other nodes have flushed their buffered read caches
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* (i.e. their page cache entries for this inode). We do not,
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* unfortunately have the option of only flushing a range like
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* the VFS does.
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*/
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gfs2_holder_init(ip->i_gl, LM_ST_DEFERRED, 0, &gh);
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rv = gfs2_glock_nq(&gh);
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if (rv)
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goto out_uninit;
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rv = gfs2_ok_for_dio(ip, offset);
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if (rv != 1)
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goto out; /* dio not valid, fall back to buffered i/o */
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/*
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* Now since we are holding a deferred (CW) lock at this point, you
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* might be wondering why this is ever needed. There is a case however
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* where we've granted a deferred local lock against a cached exclusive
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* glock. That is ok provided all granted local locks are deferred, but
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* it also means that it is possible to encounter pages which are
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* cached and possibly also mapped. So here we check for that and sort
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* them out ahead of the dio. The glock state machine will take care of
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* everything else.
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*
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* If in fact the cached glock state (gl->gl_state) is deferred (CW) in
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* the first place, mapping->nr_pages will always be zero.
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*/
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if (mapping->nrpages) {
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loff_t lstart = offset & ~(PAGE_SIZE - 1);
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loff_t len = iov_iter_count(iter);
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loff_t end = PAGE_ALIGN(offset + len) - 1;
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rv = 0;
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if (len == 0)
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goto out;
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if (test_and_clear_bit(GIF_SW_PAGED, &ip->i_flags))
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unmap_shared_mapping_range(ip->i_inode.i_mapping, offset, len);
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rv = filemap_write_and_wait_range(mapping, lstart, end);
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if (rv)
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goto out;
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if (iov_iter_rw(iter) == WRITE)
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truncate_inode_pages_range(mapping, lstart, end);
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}
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rv = __blockdev_direct_IO(iocb, inode, inode->i_sb->s_bdev, iter,
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gfs2_get_block_direct, NULL, NULL, 0);
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out:
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gfs2_glock_dq(&gh);
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out_uninit:
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gfs2_holder_uninit(&gh);
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return rv;
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}
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/**
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* gfs2_releasepage - free the metadata associated with a page
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* @page: the page that's being released
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@ -1194,7 +1098,7 @@ static const struct address_space_operations gfs2_writeback_aops = {
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.bmap = gfs2_bmap,
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.invalidatepage = gfs2_invalidatepage,
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.releasepage = gfs2_releasepage,
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.direct_IO = gfs2_direct_IO,
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.direct_IO = noop_direct_IO,
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.migratepage = buffer_migrate_page,
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.is_partially_uptodate = block_is_partially_uptodate,
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.error_remove_page = generic_error_remove_page,
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@ -1211,7 +1115,7 @@ static const struct address_space_operations gfs2_ordered_aops = {
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.bmap = gfs2_bmap,
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.invalidatepage = gfs2_invalidatepage,
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.releasepage = gfs2_releasepage,
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.direct_IO = gfs2_direct_IO,
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.direct_IO = noop_direct_IO,
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.migratepage = buffer_migrate_page,
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.is_partially_uptodate = block_is_partially_uptodate,
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.error_remove_page = generic_error_remove_page,
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@ -915,6 +915,9 @@ static int gfs2_iomap_get(struct inode *inode, loff_t pos, loff_t length,
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} else if (flags & IOMAP_WRITE) {
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u64 alloc_size;
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if (flags & IOMAP_DIRECT)
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goto out; /* (see gfs2_file_direct_write) */
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len = gfs2_alloc_size(inode, mp, len);
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alloc_size = len << inode->i_blkbits;
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if (alloc_size < iomap->length)
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@ -1082,11 +1085,18 @@ static int gfs2_iomap_begin(struct inode *inode, loff_t pos, loff_t length,
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int ret;
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trace_gfs2_iomap_start(ip, pos, length, flags);
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if (flags & IOMAP_WRITE) {
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if ((flags & IOMAP_WRITE) && !(flags & IOMAP_DIRECT)) {
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ret = gfs2_iomap_begin_write(inode, pos, length, flags, iomap);
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} else {
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ret = gfs2_iomap_get(inode, pos, length, flags, iomap, &mp);
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release_metapath(&mp);
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/*
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* Silently fall back to buffered I/O for stuffed files or if
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* we've hot a hole (see gfs2_file_direct_write).
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*/
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if ((flags & IOMAP_WRITE) && (flags & IOMAP_DIRECT) &&
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iomap->type != IOMAP_MAPPED)
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ret = -ENOTBLK;
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}
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trace_gfs2_iomap_end(ip, iomap, ret);
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return ret;
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@ -1100,7 +1110,7 @@ static int gfs2_iomap_end(struct inode *inode, loff_t pos, loff_t length,
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struct gfs2_trans *tr = current->journal_info;
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struct buffer_head *dibh = iomap->private;
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if (!(flags & IOMAP_WRITE))
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if ((flags & (IOMAP_WRITE | IOMAP_DIRECT)) != IOMAP_WRITE)
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goto out;
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if (iomap->type != IOMAP_INLINE) {
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132
fs/gfs2/file.c
132
fs/gfs2/file.c
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@ -690,6 +690,85 @@ static int gfs2_fsync(struct file *file, loff_t start, loff_t end,
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return ret ? ret : ret1;
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}
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static ssize_t gfs2_file_direct_read(struct kiocb *iocb, struct iov_iter *to)
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{
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struct file *file = iocb->ki_filp;
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struct gfs2_inode *ip = GFS2_I(file->f_mapping->host);
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size_t count = iov_iter_count(to);
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struct gfs2_holder gh;
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ssize_t ret;
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if (!count)
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return 0; /* skip atime */
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gfs2_holder_init(ip->i_gl, LM_ST_DEFERRED, 0, &gh);
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ret = gfs2_glock_nq(&gh);
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if (ret)
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goto out_uninit;
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/* fall back to buffered I/O for stuffed files */
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ret = -ENOTBLK;
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if (gfs2_is_stuffed(ip))
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goto out;
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ret = iomap_dio_rw(iocb, to, &gfs2_iomap_ops, NULL);
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out:
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gfs2_glock_dq(&gh);
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out_uninit:
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gfs2_holder_uninit(&gh);
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return ret;
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}
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static ssize_t gfs2_file_direct_write(struct kiocb *iocb, struct iov_iter *from)
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{
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struct file *file = iocb->ki_filp;
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struct inode *inode = file->f_mapping->host;
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struct gfs2_inode *ip = GFS2_I(inode);
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size_t len = iov_iter_count(from);
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loff_t offset = iocb->ki_pos;
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struct gfs2_holder gh;
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ssize_t ret;
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/*
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* Deferred lock, even if its a write, since we do no allocation on
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* this path. All we need to change is the atime, and this lock mode
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* ensures that other nodes have flushed their buffered read caches
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* (i.e. their page cache entries for this inode). We do not,
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* unfortunately, have the option of only flushing a range like the
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* VFS does.
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*/
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gfs2_holder_init(ip->i_gl, LM_ST_DEFERRED, 0, &gh);
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ret = gfs2_glock_nq(&gh);
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if (ret)
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goto out_uninit;
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/* Silently fall back to buffered I/O when writing beyond EOF */
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if (offset + len > i_size_read(&ip->i_inode))
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goto out;
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ret = iomap_dio_rw(iocb, from, &gfs2_iomap_ops, NULL);
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out:
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gfs2_glock_dq(&gh);
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out_uninit:
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gfs2_holder_uninit(&gh);
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return ret;
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}
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static ssize_t gfs2_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
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{
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ssize_t ret;
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if (iocb->ki_flags & IOCB_DIRECT) {
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ret = gfs2_file_direct_read(iocb, to);
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if (likely(ret != -ENOTBLK))
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return ret;
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iocb->ki_flags &= ~IOCB_DIRECT;
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}
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return generic_file_read_iter(iocb, to);
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}
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/**
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* gfs2_file_write_iter - Perform a write to a file
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* @iocb: The io context
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@ -707,7 +786,7 @@ static ssize_t gfs2_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
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struct file *file = iocb->ki_filp;
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struct inode *inode = file_inode(file);
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struct gfs2_inode *ip = GFS2_I(inode);
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ssize_t ret;
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ssize_t written = 0, ret;
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ret = gfs2_rsqa_alloc(ip);
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if (ret)
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@ -724,9 +803,6 @@ static ssize_t gfs2_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
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gfs2_glock_dq_uninit(&gh);
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}
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if (iocb->ki_flags & IOCB_DIRECT)
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return generic_file_write_iter(iocb, from);
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inode_lock(inode);
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ret = generic_write_checks(iocb, from);
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if (ret <= 0)
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@ -743,19 +819,55 @@ static ssize_t gfs2_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
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if (ret)
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goto out2;
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ret = iomap_file_buffered_write(iocb, from, &gfs2_iomap_ops);
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if (iocb->ki_flags & IOCB_DIRECT) {
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struct address_space *mapping = file->f_mapping;
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loff_t pos, endbyte;
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ssize_t buffered;
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written = gfs2_file_direct_write(iocb, from);
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if (written < 0 || !iov_iter_count(from))
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goto out2;
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ret = iomap_file_buffered_write(iocb, from, &gfs2_iomap_ops);
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if (unlikely(ret < 0))
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goto out2;
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buffered = ret;
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/*
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* We need to ensure that the page cache pages are written to
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* disk and invalidated to preserve the expected O_DIRECT
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* semantics.
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*/
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pos = iocb->ki_pos;
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endbyte = pos + buffered - 1;
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ret = filemap_write_and_wait_range(mapping, pos, endbyte);
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if (!ret) {
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iocb->ki_pos += buffered;
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written += buffered;
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invalidate_mapping_pages(mapping,
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pos >> PAGE_SHIFT,
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endbyte >> PAGE_SHIFT);
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} else {
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/*
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* We don't know how much we wrote, so just return
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* the number of bytes which were direct-written
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*/
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}
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} else {
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ret = iomap_file_buffered_write(iocb, from, &gfs2_iomap_ops);
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if (likely(ret > 0))
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iocb->ki_pos += ret;
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}
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out2:
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current->backing_dev_info = NULL;
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out:
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inode_unlock(inode);
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if (likely(ret > 0)) {
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iocb->ki_pos += ret;
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/* Handle various SYNC-type writes */
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ret = generic_write_sync(iocb, ret);
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}
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return ret;
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return written ? written : ret;
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}
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static int fallocate_chunk(struct inode *inode, loff_t offset, loff_t len,
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@ -1157,7 +1269,7 @@ static int gfs2_flock(struct file *file, int cmd, struct file_lock *fl)
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const struct file_operations gfs2_file_fops = {
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.llseek = gfs2_llseek,
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.read_iter = generic_file_read_iter,
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.read_iter = gfs2_file_read_iter,
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.write_iter = gfs2_file_write_iter,
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.unlocked_ioctl = gfs2_ioctl,
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.mmap = gfs2_mmap,
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@ -1187,7 +1299,7 @@ const struct file_operations gfs2_dir_fops = {
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const struct file_operations gfs2_file_fops_nolock = {
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.llseek = gfs2_llseek,
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.read_iter = generic_file_read_iter,
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.read_iter = gfs2_file_read_iter,
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.write_iter = gfs2_file_write_iter,
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.unlocked_ioctl = gfs2_ioctl,
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.mmap = gfs2_mmap,
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