[PATCH v4 31/33] afs: Locally initialise the contents of a new symlink on creation

David Howells
2024-11-08T17:36:35Z

Since we know what the contents of a symlink will be when we create it on
the server, initialise its contents locally too to avoid the need to
download it.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
---
fs/afs/dir.c | 2 ++
fs/afs/inode.c | 46 ++++++++++++++++++++++++++++++++++------
fs/afs/internal.h | 1 +
fs/netfs/buffered_read.c | 2 +-
fs/netfs/read_single.c | 2 +-
5 files changed, 45 insertions(+), 8 deletions(-)

diff --git a/fs/afs/dir.c b/fs/afs/dir.c
index d195a42cea1d..b6a202fd9926 100644
--- a/fs/afs/dir.c
+++ b/fs/afs/dir.c
@@ -1271,6 +1271,8 @@ static void afs_vnode_new_inode(struct afs_operation *op)
set_bit(AFS_VNODE_NEW_CONTENT, &vnode->flags);
if (S_ISDIR(inode->i_mode))
afs_mkdir_init_dir(vnode, dvp->vnode);
+ else if (S_ISLNK(inode->i_mode))
+ afs_init_new_symlink(vnode, op);
if (!afs_op_error(op))
afs_cache_permit(vnode, op->key, vnode->cb_break, &vp->scb);
d_instantiate(op->dentry, inode);
diff --git a/fs/afs/inode.c b/fs/afs/inode.c
index 0e3c43c40632..e9538e91f848 100644
--- a/fs/afs/inode.c
+++ b/fs/afs/inode.c
@@ -25,6 +25,24 @@
#include "internal.h"
#include "afs_fs.h"

+void afs_init_new_symlink(struct afs_vnode *vnode, struct afs_operation *op)
+{
+ size_t size = strlen(op->create.symlink) + 1;
+ size_t dsize = 0;
+ char *p;
+
+ if (netfs_alloc_folioq_buffer(NULL, &vnode->directory, &dsize, size,
+ mapping_gfp_mask(vnode->netfs.inode.i_mapping)) < 0)
+ return;
+
+ vnode->directory_size = dsize;
+ p = kmap_local_folio(folioq_folio(vnode->directory, 0), 0);
+ memcpy(p, op->create.symlink, size);
+ kunmap_local(p);
+ set_bit(AFS_VNODE_DIR_READ, &vnode->flags);
+ netfs_single_mark_inode_dirty(&vnode->netfs.inode);
+}
+
static void afs_put_link(void *arg)
{
struct folio *folio = virt_to_folio(arg);
@@ -41,15 +59,31 @@ const char *afs_get_link(struct dentry *dentry, struct inode *inode,
char *content;
ssize_t ret;

- if (atomic64_read(&vnode->cb_expires_at) == AFS_NO_CB_PROMISE ||
- !test_bit(AFS_VNODE_DIR_READ, &vnode->flags)) {
- if (!dentry)
+ if (!dentry) {
+ /* RCU pathwalk. */
+ if (!test_bit(AFS_VNODE_DIR_READ, &vnode->flags) || !afs_check_validity(vnode))
return ERR_PTR(-ECHILD);
- ret = afs_read_single(vnode, NULL);
- if (ret < 0)
- return ERR_PTR(ret);
+ goto good;
}

+ if (test_bit(AFS_VNODE_DIR_READ, &vnode->flags))
+ goto fetch;
+
+ ret = afs_validate(vnode, NULL);
+ if (ret < 0)
+ return ERR_PTR(ret);
+
+ if (!test_and_clear_bit(AFS_VNODE_ZAP_DATA, &vnode->flags) &&
+ test_bit(AFS_VNODE_DIR_READ, &vnode->flags))
+ goto good;
+
+fetch:
+ ret = afs_read_single(vnode, NULL);
+ if (ret < 0)
+ return ERR_PTR(ret);
+ set_bit(AFS_VNODE_DIR_READ, &vnode->flags);
+
+good:
folio = folioq_folio(vnode->directory, 0);
folio_get(folio);
content = kmap_local_folio(folio, 0);
diff --git a/fs/afs/internal.h b/fs/afs/internal.h
index b7d02c105340..90f407774a9a 100644
--- a/fs/afs/internal.h
+++ b/fs/afs/internal.h
@@ -1221,6 +1221,7 @@ extern void afs_fs_probe_cleanup(struct afs_net *);
*/
extern const struct afs_operation_ops afs_fetch_status_operation;

+void afs_init_new_symlink(struct afs_vnode *vnode, struct afs_operation *op);
const char *afs_get_link(struct dentry *dentry, struct inode *inode,
struct delayed_call *callback);
int afs_readlink(struct dentry *dentry, char __user *buffer, int buflen);
diff --git a/fs/netfs/buffered_read.c b/fs/netfs/buffered_read.c
index 7036e9f12b07..65d9dd71f65d 100644
--- a/fs/netfs/buffered_read.c
+++ b/fs/netfs/buffered_read.c
@@ -210,7 +210,7 @@ static void netfs_read_to_pagecache(struct netfs_io_request *rreq)

do {
struct netfs_io_subrequest *subreq;
- enum netfs_io_source source = NETFS_DOWNLOAD_FROM_SERVER;
+ enum netfs_io_source source = NETFS_SOURCE_UNKNOWN;
ssize_t slice;

subreq = netfs_alloc_subrequest(rreq);
diff --git a/fs/netfs/read_single.c b/fs/netfs/read_single.c
index 14bc61107182..fea0ecdecc53 100644
--- a/fs/netfs/read_single.c
+++ b/fs/netfs/read_single.c
@@ -97,7 +97,7 @@ static int netfs_single_dispatch_read(struct netfs_io_request *rreq)
if (!subreq)
return -ENOMEM;

- subreq->source = NETFS_DOWNLOAD_FROM_SERVER;
+ subreq->source = NETFS_SOURCE_UNKNOWN;
subreq->start = 0;
subreq->len = rreq->len;
subreq->io_iter = rreq->buffer.iter;