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iomap: Add iomap_get_folio helper

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Add an iomap_get_folio() helper that gets a folio reference based on
an iomap iterator and an offset into the address space.  Use it in
iomap_write_begin().

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
This commit is contained in:
Andreas Gruenbacher 2023-01-15 08:49:04 -08:00 committed by Darrick J. Wong
parent 40405dddd9
commit 98321b5139
2 changed files with 31 additions and 9 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

39
fs/iomap/buffered-io.c
View file

@ -457,6 +457,33 @@ bool iomap_is_partially_uptodate(struct folio *folio, size_t from, size_t count)
}
EXPORT_SYMBOL_GPL(iomap_is_partially_uptodate);
/**
* iomap_get_folio - get a folio reference for writing
* @iter: iteration structure
* @pos: start offset of write
*
* Returns a locked reference to the folio at @pos, or an error pointer if the
* folio could not be obtained.
*/
struct folio *iomap_get_folio(struct iomap_iter *iter, loff_t pos)
{
unsigned fgp = FGP_LOCK | FGP_WRITE | FGP_CREAT | FGP_STABLE | FGP_NOFS;
struct folio *folio;
if (iter->flags & IOMAP_NOWAIT)
fgp |= FGP_NOWAIT;
folio = __filemap_get_folio(iter->inode->i_mapping, pos >> PAGE_SHIFT,
fgp, mapping_gfp_mask(iter->inode->i_mapping));
if (folio)
return folio;
if (iter->flags & IOMAP_NOWAIT)
return ERR_PTR(-EAGAIN);
return ERR_PTR(-ENOMEM);
}
EXPORT_SYMBOL_GPL(iomap_get_folio);
bool iomap_release_folio(struct folio *folio, gfp_t gfp_flags)
{
trace_iomap_release_folio(folio->mapping->host, folio_pos(folio),
@ -603,12 +630,8 @@ static int iomap_write_begin(struct iomap_iter *iter, loff_t pos,
const struct iomap_page_ops *page_ops = iter->iomap.page_ops;
const struct iomap *srcmap = iomap_iter_srcmap(iter);
struct folio *folio;
unsigned fgp = FGP_LOCK | FGP_WRITE | FGP_CREAT | FGP_STABLE | FGP_NOFS;
int status = 0;
if (iter->flags & IOMAP_NOWAIT)
fgp |= FGP_NOWAIT;
BUG_ON(pos + len > iter->iomap.offset + iter->iomap.length);
if (srcmap != &iter->iomap)
BUG_ON(pos + len > srcmap->offset + srcmap->length);
@ -625,12 +648,10 @@ static int iomap_write_begin(struct iomap_iter *iter, loff_t pos,
return status;
}
folio = __filemap_get_folio(iter->inode->i_mapping, pos >> PAGE_SHIFT,
fgp, mapping_gfp_mask(iter->inode->i_mapping));
if (!folio) {
status = (iter->flags & IOMAP_NOWAIT) ? -EAGAIN : -ENOMEM;
folio = iomap_get_folio(iter, pos);
if (IS_ERR(folio)) {
__iomap_put_folio(iter, pos, 0, NULL);
return status;
return PTR_ERR(folio);
}
/*

1
include/linux/iomap.h
View file

@ -261,6 +261,7 @@ int iomap_file_buffered_write_punch_delalloc(struct inode *inode,
int iomap_read_folio(struct folio *folio, const struct iomap_ops *ops);
void iomap_readahead(struct readahead_control *, const struct iomap_ops *ops);
bool iomap_is_partially_uptodate(struct folio *, size_t from, size_t count);
struct folio *iomap_get_folio(struct iomap_iter *iter, loff_t pos);
bool iomap_release_folio(struct folio *folio, gfp_t gfp_flags);
void iomap_invalidate_folio(struct folio *folio, size_t offset, size_t len);
int iomap_file_unshare(struct inode *inode, loff_t pos, loff_t len,