diff options
author | David Howells <dhowells@redhat.com> | 2022-02-16 02:15:57 +0300 |
---|---|---|
committer | David Howells <dhowells@redhat.com> | 2023-12-28 12:45:24 +0300 |
commit | 102a7e2c598c22bd2621fa97eb1c93c89d469a12 (patch) | |
tree | 73d4ffcd3b7b96fbc5435afc1cee21c83bab9173 /fs/netfs | |
parent | 938e13a73b244278a3777f38fa915bd239b2efd2 (diff) | |
download | linux-102a7e2c598c22bd2621fa97eb1c93c89d469a12.tar.xz |
netfs: Allow buffered shared-writeable mmap through netfs_page_mkwrite()
Provide an entry point to delegate a filesystem's ->page_mkwrite() to.
This checks for conflicting writes, then attached any netfs-specific group
marking (e.g. ceph snap) to the page to be considered dirty.
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
cc: linux-fsdevel@vger.kernel.org
cc: linux-mm@kvack.org
Diffstat (limited to 'fs/netfs')
-rw-r--r-- | fs/netfs/buffered_write.c | 59 |
1 files changed, 59 insertions, 0 deletions
diff --git a/fs/netfs/buffered_write.c b/fs/netfs/buffered_write.c index f244123ab568..70cb8e98d068 100644 --- a/fs/netfs/buffered_write.c +++ b/fs/netfs/buffered_write.c @@ -416,3 +416,62 @@ ssize_t netfs_file_write_iter(struct kiocb *iocb, struct iov_iter *from) return ret; } EXPORT_SYMBOL(netfs_file_write_iter); + +/* + * Notification that a previously read-only page is about to become writable. + * Note that the caller indicates a single page of a multipage folio. + */ +vm_fault_t netfs_page_mkwrite(struct vm_fault *vmf, struct netfs_group *netfs_group) +{ + struct folio *folio = page_folio(vmf->page); + struct file *file = vmf->vma->vm_file; + struct inode *inode = file_inode(file); + vm_fault_t ret = VM_FAULT_RETRY; + int err; + + _enter("%lx", folio->index); + + sb_start_pagefault(inode->i_sb); + + if (folio_wait_writeback_killable(folio)) + goto out; + + if (folio_lock_killable(folio) < 0) + goto out; + + /* Can we see a streaming write here? */ + if (WARN_ON(!folio_test_uptodate(folio))) { + ret = VM_FAULT_SIGBUS | VM_FAULT_LOCKED; + goto out; + } + + if (netfs_folio_group(folio) != netfs_group) { + folio_unlock(folio); + err = filemap_fdatawait_range(inode->i_mapping, + folio_pos(folio), + folio_pos(folio) + folio_size(folio)); + switch (err) { + case 0: + ret = VM_FAULT_RETRY; + goto out; + case -ENOMEM: + ret = VM_FAULT_OOM; + goto out; + default: + ret = VM_FAULT_SIGBUS; + goto out; + } + } + + if (folio_test_dirty(folio)) + trace_netfs_folio(folio, netfs_folio_trace_mkwrite_plus); + else + trace_netfs_folio(folio, netfs_folio_trace_mkwrite); + netfs_set_group(folio, netfs_group); + file_update_time(file); + ret = VM_FAULT_LOCKED; +out: + sb_end_pagefault(inode->i_sb); + return ret; +} +EXPORT_SYMBOL(netfs_page_mkwrite); |