diff mbox series

[v4,58/68] afs: Skip truncation on the server of data we haven't written yet

Message ID 164021571880.640689.1837025861707111004.stgit@warthog.procyon.org.uk
State New
Headers show
Series fscache, cachefiles: Rewrite | expand

Commit Message

David Howells Dec. 22, 2021, 11:28 p.m. UTC
Don't send a truncation RPC to the server if we're only shortening data
that's in the pagecache and is beyond the server's EOF.

Also don't automatically force writeback on setattr, but do wait to store
RPCs that are in the region to be removed on a shortening truncation.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
Link: https://lore.kernel.org/r/163819663275.215744.4781075713714590913.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906972600.143852.14237659724463048094.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967177522.1823006.15336589054269480601.stgit@warthog.procyon.org.uk/ # v3
---

 fs/afs/inode.c |   45 +++++++++++++++++++++++++++++++++++----------
 1 file changed, 35 insertions(+), 10 deletions(-)
diff mbox series

Patch

diff --git a/fs/afs/inode.c b/fs/afs/inode.c
index 8db902405031..5964f8aee090 100644
--- a/fs/afs/inode.c
+++ b/fs/afs/inode.c
@@ -848,42 +848,67 @@  static const struct afs_operation_ops afs_setattr_operation = {
 int afs_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
 		struct iattr *attr)
 {
+	const unsigned int supported =
+		ATTR_SIZE | ATTR_MODE | ATTR_UID | ATTR_GID |
+		ATTR_MTIME | ATTR_MTIME_SET | ATTR_TIMES_SET | ATTR_TOUCH;
 	struct afs_operation *op;
 	struct afs_vnode *vnode = AFS_FS_I(d_inode(dentry));
+	struct inode *inode = &vnode->vfs_inode;
+	loff_t i_size;
 	int ret;
 
 	_enter("{%llx:%llu},{n=%pd},%x",
 	       vnode->fid.vid, vnode->fid.vnode, dentry,
 	       attr->ia_valid);
 
-	if (!(attr->ia_valid & (ATTR_SIZE | ATTR_MODE | ATTR_UID | ATTR_GID |
-				ATTR_MTIME | ATTR_MTIME_SET | ATTR_TIMES_SET |
-				ATTR_TOUCH))) {
+	if (!(attr->ia_valid & supported)) {
 		_leave(" = 0 [unsupported]");
 		return 0;
 	}
 
+	i_size = i_size_read(inode);
 	if (attr->ia_valid & ATTR_SIZE) {
-		if (!S_ISREG(vnode->vfs_inode.i_mode))
+		if (!S_ISREG(inode->i_mode))
 			return -EISDIR;
 
-		ret = inode_newsize_ok(&vnode->vfs_inode, attr->ia_size);
+		ret = inode_newsize_ok(inode, attr->ia_size);
 		if (ret)
 			return ret;
 
-		if (attr->ia_size == i_size_read(&vnode->vfs_inode))
+		if (attr->ia_size == i_size)
 			attr->ia_valid &= ~ATTR_SIZE;
 	}
 
 	fscache_use_cookie(afs_vnode_cache(vnode), true);
 
-	/* flush any dirty data outstanding on a regular file */
-	if (S_ISREG(vnode->vfs_inode.i_mode))
-		filemap_write_and_wait(vnode->vfs_inode.i_mapping);
-
 	/* Prevent any new writebacks from starting whilst we do this. */
 	down_write(&vnode->validate_lock);
 
+	if ((attr->ia_valid & ATTR_SIZE) && S_ISREG(inode->i_mode)) {
+		loff_t size = attr->ia_size;
+
+		/* Wait for any outstanding writes to the server to complete */
+		loff_t from = min(size, i_size);
+		loff_t to = max(size, i_size);
+		ret = filemap_fdatawait_range(inode->i_mapping, from, to);
+		if (ret < 0)
+			goto out_unlock;
+
+		/* Don't talk to the server if we're just shortening in-memory
+		 * writes that haven't gone to the server yet.
+		 */
+		if (!(attr->ia_valid & (supported & ~ATTR_SIZE & ~ATTR_MTIME)) &&
+		    attr->ia_size < i_size &&
+		    attr->ia_size > vnode->status.size) {
+			truncate_pagecache(inode, attr->ia_size);
+			fscache_resize_cookie(afs_vnode_cache(vnode),
+					      attr->ia_size);
+			i_size_write(inode, attr->ia_size);
+			ret = 0;
+			goto out_unlock;
+		}
+	}
+
 	op = afs_alloc_operation(((attr->ia_valid & ATTR_FILE) ?
 				  afs_file_key(attr->ia_file) : NULL),
 				 vnode->volume);