[RFC PATCH 27/35] netfs: Pass extra write context to write functions

David Howells
2025-03-13T23:35:36Z

Allow the filesystem to pass in an extra bit of context to certain write
functions so that netfs_page_mkwrite() and netfs_perform_write() can pass
it back to the filesystem's ->post_modify() function.

This can be used by ceph to pass in a preallocated ceph_cap_flush record.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Jeff Layton <jlayton@kernel.org>
cc: Viacheslav Dubeyko <slava@dubeyko.com>
cc: Alex Markuze <amarkuze@redhat.com>
cc: Xiubo Li <xiubli@redhat.com>
cc: Ilya Dryomov <idryomov@gmail.com>
cc: ceph-devel@vger.kernel.org
cc: linux-fsdevel@vger.kernel.org
---
fs/9p/vfs_file.c | 2 +-
fs/afs/write.c | 2 +-
fs/netfs/buffered_write.c | 21 ++++++++++++---------
fs/smb/client/file.c | 4 ++--
include/linux/netfs.h | 9 +++++----
5 files changed, 21 insertions(+), 17 deletions(-)

diff --git a/fs/9p/vfs_file.c b/fs/9p/vfs_file.c
index 348cc90bf9c5..838332d5372c 100644
--- a/fs/9p/vfs_file.c
+++ b/fs/9p/vfs_file.c
@@ -477,7 +477,7 @@ v9fs_file_mmap(struct file *filp, struct vm_area_struct *vma)
static vm_fault_t
v9fs_vm_page_mkwrite(struct vm_fault *vmf)
{
- return netfs_page_mkwrite(vmf, NULL);
+ return netfs_page_mkwrite(vmf, NULL, NULL);
}

static void v9fs_mmap_vm_close(struct vm_area_struct *vma)
diff --git a/fs/afs/write.c b/fs/afs/write.c
index 18b0a9f1615e..054f3a07d2a5 100644
--- a/fs/afs/write.c
+++ b/fs/afs/write.c
@@ -276,7 +276,7 @@ vm_fault_t afs_page_mkwrite(struct vm_fault *vmf)

if (afs_validate(AFS_FS_I(file_inode(file)), afs_file_key(file)) < 0)
return VM_FAULT_SIGBUS;
- return netfs_page_mkwrite(vmf, NULL);
+ return netfs_page_mkwrite(vmf, NULL, NULL);
}

/*
diff --git a/fs/netfs/buffered_write.c b/fs/netfs/buffered_write.c
index f3370846ba18..0245449b93e3 100644
--- a/fs/netfs/buffered_write.c
+++ b/fs/netfs/buffered_write.c
@@ -86,7 +86,8 @@ static void netfs_update_i_size(struct netfs_inode *ctx, struct inode *inode,
* netfs_perform_write - Copy data into the pagecache.
* @iocb: The operation parameters
* @iter: The source buffer
- * @netfs_group: Grouping for dirty folios (eg. ceph snaps).
+ * @netfs_group: Grouping for dirty folios (eg. ceph snaps)
+ * @fs_priv: Private data to be passed to ->post_modify()
*
* Copy data into pagecache folios attached to the inode specified by @iocb.
* The caller must hold appropriate inode locks.
@@ -97,7 +98,7 @@ static void netfs_update_i_size(struct netfs_inode *ctx, struct inode *inode,
* a new one is started.
*/
ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter,
- struct netfs_group *netfs_group)
+ struct netfs_group *netfs_group, void *fs_priv)
{
struct file *file = iocb->ki_filp;
struct inode *inode = file_inode(file);
@@ -382,7 +383,7 @@ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter,
*/
set_bit(NETFS_ICTX_MODIFIED_ATTR, &ctx->flags);
if (unlikely(ctx->ops->post_modify))
- ctx->ops->post_modify(inode);
+ ctx->ops->post_modify(inode, fs_priv);
}

if (unlikely(wreq)) {
@@ -411,7 +412,8 @@ EXPORT_SYMBOL(netfs_perform_write);
* netfs_buffered_write_iter_locked - write data to a file
* @iocb: IO state structure (file, offset, etc.)
* @from: iov_iter with data to write
- * @netfs_group: Grouping for dirty folios (eg. ceph snaps).
+ * @netfs_group: Grouping for dirty folios (eg. ceph snaps)
+ * @fs_priv: Private data to be passed to ->post_modify()
*
* This function does all the work needed for actually writing data to a
* file. It does all basic checks, removes SUID from the file, updates
@@ -431,7 +433,7 @@ EXPORT_SYMBOL(netfs_perform_write);
* * negative error code if no data has been written at all
*/
ssize_t netfs_buffered_write_iter_locked(struct kiocb *iocb, struct iov_iter *from,
- struct netfs_group *netfs_group)
+ struct netfs_group *netfs_group, void *fs_priv)
{
struct file *file = iocb->ki_filp;
ssize_t ret;
@@ -446,7 +448,7 @@ ssize_t netfs_buffered_write_iter_locked(struct kiocb *iocb, struct iov_iter *fr
if (ret)
return ret;

- return netfs_perform_write(iocb, from, netfs_group);
+ return netfs_perform_write(iocb, from, netfs_group, fs_priv);
}
EXPORT_SYMBOL(netfs_buffered_write_iter_locked);

@@ -485,7 +487,7 @@ ssize_t netfs_file_write_iter(struct kiocb *iocb, struct iov_iter *from)

ret = generic_write_checks(iocb, from);
if (ret > 0)
- ret = netfs_buffered_write_iter_locked(iocb, from, NULL);
+ ret = netfs_buffered_write_iter_locked(iocb, from, NULL, NULL);
netfs_end_io_write(inode);
if (ret > 0)
ret = generic_write_sync(iocb, ret);
@@ -499,7 +501,8 @@ EXPORT_SYMBOL(netfs_file_write_iter);
* we only track group on a per-folio basis, so we block more often than
* we might otherwise.
*/
-vm_fault_t netfs_page_mkwrite(struct vm_fault *vmf, struct netfs_group *netfs_group)
+vm_fault_t netfs_page_mkwrite(struct vm_fault *vmf, struct netfs_group *netfs_group,
+ void *fs_priv)
{
struct netfs_group *group;
struct folio *folio = page_folio(vmf->page);
@@ -554,7 +557,7 @@ vm_fault_t netfs_page_mkwrite(struct vm_fault *vmf, struct netfs_group *netfs_gr
file_update_time(file);
set_bit(NETFS_ICTX_MODIFIED_ATTR, &ictx->flags);
if (ictx->ops->post_modify)
- ictx->ops->post_modify(inode);
+ ictx->ops->post_modify(inode, fs_priv);
ret = VM_FAULT_LOCKED;
out:
sb_end_pagefault(inode->i_sb);
diff --git a/fs/smb/client/file.c b/fs/smb/client/file.c
index 8582cf61242c..4329c2bbf74f 100644
--- a/fs/smb/client/file.c
+++ b/fs/smb/client/file.c
@@ -2779,7 +2779,7 @@ cifs_writev(struct kiocb *iocb, struct iov_iter *from)
goto out;
}

- rc = netfs_buffered_write_iter_locked(iocb, from, NULL);
+ rc = netfs_buffered_write_iter_locked(iocb, from, NULL, NULL);

out:
up_read(&cinode->lock_sem);
@@ -2955,7 +2955,7 @@ cifs_strict_readv(struct kiocb *iocb, struct iov_iter *to)

static vm_fault_t cifs_page_mkwrite(struct vm_fault *vmf)
{
- return netfs_page_mkwrite(vmf, NULL);
+ return netfs_page_mkwrite(vmf, NULL, NULL);
}

static const struct vm_operations_struct cifs_file_vm_ops = {
diff --git a/include/linux/netfs.h b/include/linux/netfs.h
index ec1c51697c04..a67297de8a20 100644
--- a/include/linux/netfs.h
+++ b/include/linux/netfs.h
@@ -335,7 +335,7 @@ struct netfs_request_ops {

/* Modification handling */
void (*update_i_size)(struct inode *inode, loff_t i_size);
- void (*post_modify)(struct inode *inode);
+ void (*post_modify)(struct inode *inode, void *fs_priv);

/* Write request handling */
void (*begin_writeback)(struct netfs_io_request *wreq);
@@ -435,9 +435,9 @@ ssize_t netfs_file_read_iter(struct kiocb *iocb, struct iov_iter *iter);

/* High-level write API */
ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter,
- struct netfs_group *netfs_group);
+ struct netfs_group *netfs_group, void *fs_priv);
ssize_t netfs_buffered_write_iter_locked(struct kiocb *iocb, struct iov_iter *from,
- struct netfs_group *netfs_group);
+ struct netfs_group *netfs_group, void *fs_priv);
ssize_t netfs_unbuffered_write_iter(struct kiocb *iocb, struct iov_iter *from);
ssize_t netfs_unbuffered_write_iter_locked(struct kiocb *iocb, struct iov_iter *iter,
struct netfs_group *netfs_group);
@@ -466,7 +466,8 @@ void netfs_invalidate_folio(struct folio *folio, size_t offset, size_t length);
bool netfs_release_folio(struct folio *folio, gfp_t gfp);

/* VMA operations API. */
-vm_fault_t netfs_page_mkwrite(struct vm_fault *vmf, struct netfs_group *netfs_group);
+vm_fault_t netfs_page_mkwrite(struct vm_fault *vmf, struct netfs_group *netfs_group,
+ void *fs_priv);

/* (Sub)request management API. */
void netfs_read_subreq_progress(struct netfs_io_subrequest *subreq);