Commit e999a5c5 authored by Matthew Wilcox's avatar Matthew Wilcox Committed by Theodore Ts'o
Browse files

fs: Add FGP_WRITEBEGIN 



This particular combination of flags is used by most filesystems
in their ->write_begin method, although it does find use in a
few other places.  Before folios, it warranted its own function
(grab_cache_page_write_begin()), but I think that just having specialised
flags is enough.  It certainly helps the few places that have been
converted from grab_cache_page_write_begin() to __filemap_get_folio().

Signed-off-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Link: https://lore.kernel.org/r/20230324180129.1220691-2-willy@infradead.org


Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
parent 361eb69f

fs/ext4/move_extent.c

+2 −3
Original line number Diff line number Diff line
@@ -126,7 +126,6 @@ mext_folio_double_lock(struct inode *inode1, struct inode *inode2, 
{

	struct address_space *mapping[2];

	unsigned int flags;

	unsigned fgp_flags = FGP_LOCK | FGP_WRITE | FGP_CREAT | FGP_STABLE;



	BUG_ON(!inode1 || !inode2);

	if (inode1 < inode2) {
@@ -139,14 +138,14 @@ mext_folio_double_lock(struct inode *inode1, struct inode *inode2, 
	}



	flags = memalloc_nofs_save();

	folio[0] = __filemap_get_folio(mapping[0], index1, fgp_flags,

	folio[0] = __filemap_get_folio(mapping[0], index1, FGP_WRITEBEGIN,

			mapping_gfp_mask(mapping[0]));

	if (!folio[0]) {

		memalloc_nofs_restore(flags);

		return -ENOMEM;

	}



	folio[1] = __filemap_get_folio(mapping[1], index2, fgp_flags,

	folio[1] = __filemap_get_folio(mapping[1], index2, FGP_WRITEBEGIN,

			mapping_gfp_mask(mapping[1]));

	memalloc_nofs_restore(flags);

	if (!folio[1]) {

fs/iomap/buffered-io.c

+1 −1
Original line number Diff line number Diff line
@@ -467,7 +467,7 @@ EXPORT_SYMBOL_GPL(iomap_is_partially_uptodate); 
 */

struct folio *iomap_get_folio(struct iomap_iter *iter, loff_t pos)

{

	unsigned fgp = FGP_LOCK | FGP_WRITE | FGP_CREAT | FGP_STABLE | FGP_NOFS;

	unsigned fgp = FGP_WRITEBEGIN | FGP_NOFS;

	struct folio *folio;



	if (iter->flags & IOMAP_NOWAIT)

fs/netfs/buffered_read.c

+1 −2
Original line number Diff line number Diff line
@@ -341,14 +341,13 @@ int netfs_write_begin(struct netfs_inode *ctx, 
{

	struct netfs_io_request *rreq;

	struct folio *folio;

	unsigned int fgp_flags = FGP_LOCK | FGP_WRITE | FGP_CREAT | FGP_STABLE;

	pgoff_t index = pos >> PAGE_SHIFT;

	int ret;



	DEFINE_READAHEAD(ractl, file, NULL, mapping, index);



retry:

	folio = __filemap_get_folio(mapping, index, fgp_flags,

	folio = __filemap_get_folio(mapping, index, FGP_WRITEBEGIN,

				    mapping_gfp_mask(mapping));

	if (!folio)

		return -ENOMEM;

fs/nfs/file.c

+2 −10
Original line number Diff line number Diff line
@@ -306,15 +306,6 @@ static bool nfs_want_read_modify_write(struct file *file, struct folio *folio, 
	return false;

}



static struct folio *

nfs_folio_grab_cache_write_begin(struct address_space *mapping, pgoff_t index)

{

	unsigned fgp_flags = FGP_LOCK | FGP_WRITE | FGP_CREAT | FGP_STABLE;



	return __filemap_get_folio(mapping, index, fgp_flags,

				   mapping_gfp_mask(mapping));

}



/*

 * This does the "real" work of the write. We must allocate and lock the

 * page to be sent back to the generic routine, which then copies the
@@ -335,7 +326,8 @@ static int nfs_write_begin(struct file *file, struct address_space *mapping, 
		file, mapping->host->i_ino, len, (long long) pos);



start:

	folio = nfs_folio_grab_cache_write_begin(mapping, pos >> PAGE_SHIFT);

	folio = __filemap_get_folio(mapping, pos >> PAGE_SHIFT, FGP_WRITEBEGIN,

				    mapping_gfp_mask(mapping));

	if (!folio)

		return -ENOMEM;

	*pagep = &folio->page;

include/linux/pagemap.h

+2 −0
Original line number Diff line number Diff line
@@ -507,6 +507,8 @@ pgoff_t page_cache_prev_miss(struct address_space *mapping, 
#define FGP_ENTRY		0x00000080

#define FGP_STABLE		0x00000100



#define FGP_WRITEBEGIN		(FGP_LOCK | FGP_WRITE | FGP_CREAT | FGP_STABLE)



struct folio *__filemap_get_folio(struct address_space *mapping, pgoff_t index,

		int fgp_flags, gfp_t gfp);

struct page *pagecache_get_page(struct address_space *mapping, pgoff_t index,