diff mbox series

[SRU,N,1/1] UBUNTU: SAUCE: Revert "9p: Use netfslib read/write_iter"

Message ID 20240512061136.726299-2-andrea.righi@canonical.com
State New
Headers show
Series fix autopkgtest-virt-qemu regression with 6.8 | expand

Commit Message

Andrea Righi May 12, 2024, 6:09 a.m. UTC
BugLink: https://bugs.launchpad.net/bugs/2056461

Revert commit 80105ed2fd27 ("9p: Use netfslib read/write_iter") that
seems to introduce a regression in our autopkgtest workflow.

Signed-off-by: Andrea Righi <andrea.righi@canonical.com>
---
 fs/9p/vfs_addr.c       | 293 +++++++++++++++++++++++++++++++----------
 fs/9p/vfs_file.c       |  89 +++++++++++--
 fs/9p/vfs_inode.c      |   5 +-
 fs/9p/vfs_inode_dotl.c |   7 +-
 4 files changed, 309 insertions(+), 85 deletions(-)
diff mbox series

Patch

diff --git a/fs/9p/vfs_addr.c b/fs/9p/vfs_addr.c
index 047855033d32..055b672a247d 100644
--- a/fs/9p/vfs_addr.c
+++ b/fs/9p/vfs_addr.c
@@ -19,45 +19,12 @@ 
 #include <linux/netfs.h>
 #include <net/9p/9p.h>
 #include <net/9p/client.h>
-#include <trace/events/netfs.h>
 
 #include "v9fs.h"
 #include "v9fs_vfs.h"
 #include "cache.h"
 #include "fid.h"
 
-static void v9fs_upload_to_server(struct netfs_io_subrequest *subreq)
-{
-	struct p9_fid *fid = subreq->rreq->netfs_priv;
-	int err, len;
-
-	trace_netfs_sreq(subreq, netfs_sreq_trace_submit);
-	len = p9_client_write(fid, subreq->start, &subreq->io_iter, &err);
-	netfs_write_subrequest_terminated(subreq, len ?: err, false);
-}
-
-static void v9fs_upload_to_server_worker(struct work_struct *work)
-{
-	struct netfs_io_subrequest *subreq =
-		container_of(work, struct netfs_io_subrequest, work);
-
-	v9fs_upload_to_server(subreq);
-}
-
-/*
- * Set up write requests for a writeback slice.  We need to add a write request
- * for each write we want to make.
- */
-static void v9fs_create_write_requests(struct netfs_io_request *wreq, loff_t start, size_t len)
-{
-	struct netfs_io_subrequest *subreq;
-
-	subreq = netfs_create_write_request(wreq, NETFS_UPLOAD_TO_SERVER,
-					    start, len, v9fs_upload_to_server_worker);
-	if (subreq)
-		netfs_queue_write_request(subreq);
-}
-
 /**
  * v9fs_issue_read - Issue a read from 9P
  * @subreq: The read to make
@@ -66,10 +33,14 @@  static void v9fs_issue_read(struct netfs_io_subrequest *subreq)
 {
 	struct netfs_io_request *rreq = subreq->rreq;
 	struct p9_fid *fid = rreq->netfs_priv;
+	struct iov_iter to;
+	loff_t pos = subreq->start + subreq->transferred;
+	size_t len = subreq->len   - subreq->transferred;
 	int total, err;
 
-	total = p9_client_read(fid, subreq->start + subreq->transferred,
-			       &subreq->io_iter, &err);
+	iov_iter_xarray(&to, ITER_DEST, &rreq->mapping->i_pages, pos, len);
+
+	total = p9_client_read(fid, pos, &to, &err);
 
 	/* if we just extended the file size, any portion not in
 	 * cache won't be on server and is zeroes */
@@ -79,42 +50,25 @@  static void v9fs_issue_read(struct netfs_io_subrequest *subreq)
 }
 
 /**
- * v9fs_init_request - Initialise a request
+ * v9fs_init_request - Initialise a read request
  * @rreq: The read request
  * @file: The file being read from
  */
 static int v9fs_init_request(struct netfs_io_request *rreq, struct file *file)
 {
-	struct p9_fid *fid;
-	bool writing = (rreq->origin == NETFS_READ_FOR_WRITE ||
-			rreq->origin == NETFS_WRITEBACK ||
-			rreq->origin == NETFS_WRITETHROUGH ||
-			rreq->origin == NETFS_LAUNDER_WRITE ||
-			rreq->origin == NETFS_UNBUFFERED_WRITE ||
-			rreq->origin == NETFS_DIO_WRITE);
-
-	if (file) {
-		fid = file->private_data;
-		if (!fid)
-			goto no_fid;
-		p9_fid_get(fid);
-	} else {
-		fid = v9fs_fid_find_inode(rreq->inode, writing, INVALID_UID, true);
-		if (!fid)
-			goto no_fid;
-	}
+	struct p9_fid *fid = file->private_data;
+
+	BUG_ON(!fid);
 
 	/* we might need to read from a fid that was opened write-only
 	 * for read-modify-write of page cache, use the writeback fid
 	 * for that */
-	WARN_ON(rreq->origin == NETFS_READ_FOR_WRITE && !(fid->mode & P9_ORDWR));
+	WARN_ON(rreq->origin == NETFS_READ_FOR_WRITE &&
+			!(fid->mode & P9_ORDWR));
+
+	p9_fid_get(fid);
 	rreq->netfs_priv = fid;
 	return 0;
-
-no_fid:
-	WARN_ONCE(1, "folio expected an open fid inode->i_ino=%lx\n",
-		  rreq->inode->i_ino);
-	return -EINVAL;
 }
 
 /**
@@ -132,16 +86,217 @@  const struct netfs_request_ops v9fs_req_ops = {
 	.init_request		= v9fs_init_request,
 	.free_request		= v9fs_free_request,
 	.issue_read		= v9fs_issue_read,
-	.create_write_requests	= v9fs_create_write_requests,
 };
 
+#ifdef CONFIG_9P_FSCACHE
+static void v9fs_write_to_cache_done(void *priv, ssize_t transferred_or_error,
+				     bool was_async)
+{
+	struct v9fs_inode *v9inode = priv;
+	__le32 version;
+
+	if (IS_ERR_VALUE(transferred_or_error) &&
+	    transferred_or_error != -ENOBUFS) {
+		version = cpu_to_le32(v9inode->qid.version);
+		fscache_invalidate(v9fs_inode_cookie(v9inode), &version,
+				   i_size_read(&v9inode->netfs.inode), 0);
+	}
+}
+#endif
+
+static int v9fs_vfs_write_folio_locked(struct folio *folio)
+{
+	struct inode *inode = folio_inode(folio);
+	loff_t start = folio_pos(folio);
+	loff_t i_size = i_size_read(inode);
+	struct iov_iter from;
+	size_t len = folio_size(folio);
+	struct p9_fid *writeback_fid;
+	int err;
+	struct v9fs_inode __maybe_unused *v9inode = V9FS_I(inode);
+	struct fscache_cookie __maybe_unused *cookie = v9fs_inode_cookie(v9inode);
+
+	if (start >= i_size)
+		return 0; /* Simultaneous truncation occurred */
+
+	len = min_t(loff_t, i_size - start, len);
+
+	iov_iter_xarray(&from, ITER_SOURCE, &folio_mapping(folio)->i_pages, start, len);
+
+	writeback_fid = v9fs_fid_find_inode(inode, true, INVALID_UID, true);
+	if (!writeback_fid) {
+		WARN_ONCE(1, "folio expected an open fid inode->i_private=%p\n",
+			inode->i_private);
+		return -EINVAL;
+	}
+
+	folio_wait_fscache(folio);
+	folio_start_writeback(folio);
+
+	p9_client_write(writeback_fid, start, &from, &err);
+
+#ifdef CONFIG_9P_FSCACHE
+	if (err == 0 &&
+		fscache_cookie_enabled(cookie) &&
+		test_bit(FSCACHE_COOKIE_IS_CACHING, &cookie->flags)) {
+		folio_start_fscache(folio);
+		fscache_write_to_cache(v9fs_inode_cookie(v9inode),
+					folio_mapping(folio), start, len, i_size,
+					v9fs_write_to_cache_done, v9inode,
+					true);
+	}
+#endif
+
+	folio_end_writeback(folio);
+	p9_fid_put(writeback_fid);
+
+	return err;
+}
+
+static int v9fs_vfs_writepage(struct page *page, struct writeback_control *wbc)
+{
+	struct folio *folio = page_folio(page);
+	int retval;
+
+	p9_debug(P9_DEBUG_VFS, "folio %p\n", folio);
+
+	retval = v9fs_vfs_write_folio_locked(folio);
+	if (retval < 0) {
+		if (retval == -EAGAIN) {
+			folio_redirty_for_writepage(wbc, folio);
+			retval = 0;
+		} else {
+			mapping_set_error(folio_mapping(folio), retval);
+		}
+	} else
+		retval = 0;
+
+	folio_unlock(folio);
+	return retval;
+}
+
+static int v9fs_launder_folio(struct folio *folio)
+{
+	int retval;
+
+	if (folio_clear_dirty_for_io(folio)) {
+		retval = v9fs_vfs_write_folio_locked(folio);
+		if (retval)
+			return retval;
+	}
+	folio_wait_fscache(folio);
+	return 0;
+}
+
+/**
+ * v9fs_direct_IO - 9P address space operation for direct I/O
+ * @iocb: target I/O control block
+ * @iter: The data/buffer to use
+ *
+ * The presence of v9fs_direct_IO() in the address space ops vector
+ * allowes open() O_DIRECT flags which would have failed otherwise.
+ *
+ * In the non-cached mode, we shunt off direct read and write requests before
+ * the VFS gets them, so this method should never be called.
+ *
+ * Direct IO is not 'yet' supported in the cached mode. Hence when
+ * this routine is called through generic_file_aio_read(), the read/write fails
+ * with an error.
+ *
+ */
+static ssize_t
+v9fs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
+{
+	struct file *file = iocb->ki_filp;
+	loff_t pos = iocb->ki_pos;
+	ssize_t n;
+	int err = 0;
+
+	if (iov_iter_rw(iter) == WRITE) {
+		n = p9_client_write(file->private_data, pos, iter, &err);
+		if (n) {
+			struct inode *inode = file_inode(file);
+			loff_t i_size = i_size_read(inode);
+
+			if (pos + n > i_size)
+				inode_add_bytes(inode, pos + n - i_size);
+		}
+	} else {
+		n = p9_client_read(file->private_data, pos, iter, &err);
+	}
+	return n ? n : err;
+}
+
+static int v9fs_write_begin(struct file *filp, struct address_space *mapping,
+			    loff_t pos, unsigned int len,
+			    struct page **subpagep, void **fsdata)
+{
+	int retval;
+	struct folio *folio;
+	struct v9fs_inode *v9inode = V9FS_I(mapping->host);
+
+	p9_debug(P9_DEBUG_VFS, "filp %p, mapping %p\n", filp, mapping);
+
+	/* Prefetch area to be written into the cache if we're caching this
+	 * file.  We need to do this before we get a lock on the page in case
+	 * there's more than one writer competing for the same cache block.
+	 */
+	retval = netfs_write_begin(&v9inode->netfs, filp, mapping, pos, len, &folio, fsdata);
+	if (retval < 0)
+		return retval;
+
+	*subpagep = &folio->page;
+	return retval;
+}
+
+static int v9fs_write_end(struct file *filp, struct address_space *mapping,
+			  loff_t pos, unsigned int len, unsigned int copied,
+			  struct page *subpage, void *fsdata)
+{
+	loff_t last_pos = pos + copied;
+	struct folio *folio = page_folio(subpage);
+	struct inode *inode = mapping->host;
+
+	p9_debug(P9_DEBUG_VFS, "filp %p, mapping %p\n", filp, mapping);
+
+	if (!folio_test_uptodate(folio)) {
+		if (unlikely(copied < len)) {
+			copied = 0;
+			goto out;
+		}
+
+		folio_mark_uptodate(folio);
+	}
+
+	/*
+	 * No need to use i_size_read() here, the i_size
+	 * cannot change under us because we hold the i_mutex.
+	 */
+	if (last_pos > inode->i_size) {
+		inode_add_bytes(inode, last_pos - inode->i_size);
+		i_size_write(inode, last_pos);
+#ifdef CONFIG_9P_FSCACHE
+		fscache_update_cookie(v9fs_inode_cookie(V9FS_I(inode)), NULL,
+			&last_pos);
+#endif
+	}
+	folio_mark_dirty(folio);
+out:
+	folio_unlock(folio);
+	folio_put(folio);
+
+	return copied;
+}
+
 const struct address_space_operations v9fs_addr_operations = {
-	.read_folio		= netfs_read_folio,
-	.readahead		= netfs_readahead,
-	.dirty_folio		= netfs_dirty_folio,
-	.release_folio		= netfs_release_folio,
-	.invalidate_folio	= netfs_invalidate_folio,
-	.launder_folio		= netfs_launder_folio,
-	.direct_IO		= noop_direct_IO,
-	.writepages		= netfs_writepages,
+	.read_folio	= netfs_read_folio,
+	.readahead	= netfs_readahead,
+	.dirty_folio	= netfs_dirty_folio,
+	.writepage	= v9fs_vfs_writepage,
+	.write_begin	= v9fs_write_begin,
+	.write_end	= v9fs_write_end,
+	.release_folio	= netfs_release_folio,
+	.invalidate_folio = netfs_invalidate_folio,
+	.launder_folio	= v9fs_launder_folio,
+	.direct_IO	= v9fs_direct_IO,
 };
diff --git a/fs/9p/vfs_file.c b/fs/9p/vfs_file.c
index bae330c2f0cf..11cd8d23f6f2 100644
--- a/fs/9p/vfs_file.c
+++ b/fs/9p/vfs_file.c
@@ -353,15 +353,25 @@  static ssize_t
 v9fs_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
 {
 	struct p9_fid *fid = iocb->ki_filp->private_data;
+	int ret, err = 0;
 
 	p9_debug(P9_DEBUG_VFS, "fid %d count %zu offset %lld\n",
 		 fid->fid, iov_iter_count(to), iocb->ki_pos);
 
-	if (fid->mode & P9L_DIRECT)
-		return netfs_unbuffered_read_iter(iocb, to);
+	if (!(fid->mode & P9L_DIRECT)) {
+		p9_debug(P9_DEBUG_VFS, "(cached)\n");
+		return generic_file_read_iter(iocb, to);
+	}
+
+	if (iocb->ki_filp->f_flags & O_NONBLOCK)
+		ret = p9_client_read_once(fid, iocb->ki_pos, to, &err);
+	else
+		ret = p9_client_read(fid, iocb->ki_pos, to, &err);
+	if (!ret)
+		return err;
 
-	p9_debug(P9_DEBUG_VFS, "(cached)\n");
-	return netfs_file_read_iter(iocb, to);
+	iocb->ki_pos += ret;
+	return ret;
 }
 
 /*
@@ -397,14 +407,46 @@  v9fs_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 {
 	struct file *file = iocb->ki_filp;
 	struct p9_fid *fid = file->private_data;
+	ssize_t retval;
+	loff_t origin;
+	int err = 0;
 
 	p9_debug(P9_DEBUG_VFS, "fid %d\n", fid->fid);
 
-	if (fid->mode & (P9L_DIRECT | P9L_NOWRITECACHE))
-		return netfs_unbuffered_write_iter(iocb, from);
+	if (!(fid->mode & (P9L_DIRECT | P9L_NOWRITECACHE))) {
+		p9_debug(P9_DEBUG_CACHE, "(cached)\n");
+		return generic_file_write_iter(iocb, from);
+	}
 
-	p9_debug(P9_DEBUG_CACHE, "(cached)\n");
-	return netfs_file_write_iter(iocb, from);
+	retval = generic_write_checks(iocb, from);
+	if (retval <= 0)
+		return retval;
+
+	origin = iocb->ki_pos;
+	retval = p9_client_write(file->private_data, iocb->ki_pos, from, &err);
+	if (retval > 0) {
+		struct inode *inode = file_inode(file);
+		loff_t i_size;
+		unsigned long pg_start, pg_end;
+
+		pg_start = origin >> PAGE_SHIFT;
+		pg_end = (origin + retval - 1) >> PAGE_SHIFT;
+		if (inode->i_mapping && inode->i_mapping->nrpages)
+			invalidate_inode_pages2_range(inode->i_mapping,
+						      pg_start, pg_end);
+		iocb->ki_pos += retval;
+		i_size = i_size_read(inode);
+		if (iocb->ki_pos > i_size) {
+			inode_add_bytes(inode, iocb->ki_pos - i_size);
+			/*
+			 * Need to serialize against i_size_write() in
+			 * v9fs_stat2inode()
+			 */
+			v9fs_i_size_write(inode, iocb->ki_pos);
+		}
+		return retval;
+	}
+	return err;
 }
 
 static int v9fs_file_fsync(struct file *filp, loff_t start, loff_t end,
@@ -477,7 +519,36 @@  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);
+	struct folio *folio = page_folio(vmf->page);
+	struct file *filp = vmf->vma->vm_file;
+	struct inode *inode = file_inode(filp);
+
+
+	p9_debug(P9_DEBUG_VFS, "folio %p fid %lx\n",
+		 folio, (unsigned long)filp->private_data);
+
+	/* Wait for the page to be written to the cache before we allow it to
+	 * be modified.  We then assume the entire page will need writing back.
+	 */
+#ifdef CONFIG_9P_FSCACHE
+	if (folio_test_fscache(folio) &&
+	    folio_wait_fscache_killable(folio) < 0)
+		return VM_FAULT_NOPAGE;
+#endif
+
+	/* Update file times before taking page lock */
+	file_update_time(filp);
+
+	if (folio_lock_killable(folio) < 0)
+		return VM_FAULT_RETRY;
+	if (folio_mapping(folio) != inode->i_mapping)
+		goto out_unlock;
+	folio_wait_stable(folio);
+
+	return VM_FAULT_LOCKED;
+out_unlock:
+	folio_unlock(folio);
+	return VM_FAULT_NOPAGE;
 }
 
 static void v9fs_mmap_vm_close(struct vm_area_struct *vma)
diff --git a/fs/9p/vfs_inode.c b/fs/9p/vfs_inode.c
index 32572982f72e..e9b744b9978c 100644
--- a/fs/9p/vfs_inode.c
+++ b/fs/9p/vfs_inode.c
@@ -373,8 +373,10 @@  void v9fs_evict_inode(struct inode *inode)
 
 	truncate_inode_pages_final(&inode->i_data);
 
+#ifdef CONFIG_9P_FSCACHE
 	version = cpu_to_le32(v9inode->qid.version);
 	netfs_clear_inode_writeback(inode, &version);
+#endif
 
 	clear_inode(inode);
 	filemap_fdatawrite(&inode->i_data);
@@ -1110,7 +1112,7 @@  static int v9fs_vfs_setattr(struct mnt_idmap *idmap,
 	if ((iattr->ia_valid & ATTR_SIZE) &&
 		 iattr->ia_size != i_size_read(inode)) {
 		truncate_setsize(inode, iattr->ia_size);
-		netfs_resize_file(netfs_inode(inode), iattr->ia_size, true);
+		truncate_pagecache(inode, iattr->ia_size);
 
 #ifdef CONFIG_9P_FSCACHE
 		if (v9ses->cache & CACHE_FSCACHE) {
@@ -1178,7 +1180,6 @@  v9fs_stat2inode(struct p9_wstat *stat, struct inode *inode,
 	mode |= inode->i_mode & ~S_IALLUGO;
 	inode->i_mode = mode;
 
-	v9inode->netfs.remote_i_size = stat->length;
 	if (!(flags & V9FS_STAT2INODE_KEEP_ISIZE))
 		v9fs_i_size_write(inode, stat->length);
 	/* not real number of blocks, but 512 byte ones ... */
diff --git a/fs/9p/vfs_inode_dotl.c b/fs/9p/vfs_inode_dotl.c
index 3505227e1704..d0636b99f05b 100644
--- a/fs/9p/vfs_inode_dotl.c
+++ b/fs/9p/vfs_inode_dotl.c
@@ -599,7 +599,7 @@  int v9fs_vfs_setattr_dotl(struct mnt_idmap *idmap,
 	if ((iattr->ia_valid & ATTR_SIZE) && iattr->ia_size !=
 		 i_size_read(inode)) {
 		truncate_setsize(inode, iattr->ia_size);
-		netfs_resize_file(netfs_inode(inode), iattr->ia_size, true);
+		truncate_pagecache(inode, iattr->ia_size);
 
 #ifdef CONFIG_9P_FSCACHE
 		if (v9ses->cache & CACHE_FSCACHE)
@@ -656,7 +656,6 @@  v9fs_stat2inode_dotl(struct p9_stat_dotl *stat, struct inode *inode,
 		mode |= inode->i_mode & ~S_IALLUGO;
 		inode->i_mode = mode;
 
-		v9inode->netfs.remote_i_size = stat->st_size;
 		if (!(flags & V9FS_STAT2INODE_KEEP_ISIZE))
 			v9fs_i_size_write(inode, stat->st_size);
 		inode->i_blocks = stat->st_blocks;
@@ -685,10 +684,8 @@  v9fs_stat2inode_dotl(struct p9_stat_dotl *stat, struct inode *inode,
 			inode->i_mode = mode;
 		}
 		if (!(flags & V9FS_STAT2INODE_KEEP_ISIZE) &&
-		    stat->st_result_mask & P9_STATS_SIZE) {
-			v9inode->netfs.remote_i_size = stat->st_size;
+		    stat->st_result_mask & P9_STATS_SIZE)
 			v9fs_i_size_write(inode, stat->st_size);
-		}
 		if (stat->st_result_mask & P9_STATS_BLOCKS)
 			inode->i_blocks = stat->st_blocks;
 	}