[PATCH 2/3] afs: Split afs_pagecache_valid() out of afs_validate()

Matthew Wilcox (Oracle)
2023-02-08T14:53:48Z

For the map_pages() method, we need a test that does not sleep. The page
fault handler will continue to call the fault() method where we can
sleep and do the full revalidation there.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
fs/afs/file.c | 14 ++------------
fs/afs/inode.c | 27 +++++++++++++++++++--------
fs/afs/internal.h | 1 +
3 files changed, 22 insertions(+), 20 deletions(-)

diff --git a/fs/afs/file.c b/fs/afs/file.c
index 68d6d5dc608d..719b31374879 100644
--- a/fs/afs/file.c
+++ b/fs/afs/file.c
@@ -569,20 +569,10 @@ static void afs_vm_close(struct vm_area_struct *vma)
static vm_fault_t afs_vm_map_pages(struct vm_fault *vmf, pgoff_t start_pgoff, pgoff_t end_pgoff)
{
struct afs_vnode *vnode = AFS_FS_I(file_inode(vmf->vma->vm_file));
- struct afs_file *af = vmf->vma->vm_file->private_data;

- switch (afs_validate(vnode, af->key)) {
- case 0:
+ if (afs_pagecache_valid(vnode))
return filemap_map_pages(vmf, start_pgoff, end_pgoff);
- case -ENOMEM:
- return VM_FAULT_OOM;
- case -EINTR:
- case -ERESTARTSYS:
- return VM_FAULT_RETRY;
- case -ESTALE:
- default:
- return VM_FAULT_SIGBUS;
- }
+ return 0;
}

static ssize_t afs_file_read_iter(struct kiocb *iocb, struct iov_iter *iter)
diff --git a/fs/afs/inode.c b/fs/afs/inode.c
index 0167e96e5198..b1bdffd5e888 100644
--- a/fs/afs/inode.c
+++ b/fs/afs/inode.c
@@ -667,6 +667,24 @@ bool afs_check_validity(struct afs_vnode *vnode)
return false;
}

+/*
+ * Returns true if the pagecache is still valid. Does not sleep.
+ */
+bool afs_pagecache_valid(struct afs_vnode *vnode)
+{
+ if (unlikely(test_bit(AFS_VNODE_DELETED, &vnode->flags))) {
+ if (vnode->netfs.inode.i_nlink)
+ clear_nlink(&vnode->netfs.inode);
+ return true;
+ }
+
+ if (test_bit(AFS_VNODE_CB_PROMISED, &vnode->flags) &&
+ afs_check_validity(vnode))
+ return true;
+
+ return false;
+}
+
/*
* validate a vnode/inode
* - there are several things we need to check
@@ -684,14 +702,7 @@ int afs_validate(struct afs_vnode *vnode, struct key *key)
vnode->fid.vid, vnode->fid.vnode, vnode->flags,
key_serial(key));

- if (unlikely(test_bit(AFS_VNODE_DELETED, &vnode->flags))) {
- if (vnode->netfs.inode.i_nlink)
- clear_nlink(&vnode->netfs.inode);
- goto valid;
- }
-
- if (test_bit(AFS_VNODE_CB_PROMISED, &vnode->flags) &&
- afs_check_validity(vnode))
+ if (afs_pagecache_valid(vnode))
goto valid;

down_write(&vnode->validate_lock);
diff --git a/fs/afs/internal.h b/fs/afs/internal.h
index ad8523d0d038..5c95df6621f9 100644
--- a/fs/afs/internal.h
+++ b/fs/afs/internal.h
@@ -1171,6 +1171,7 @@ extern struct inode *afs_iget(struct afs_operation *, struct afs_vnode_param *);
extern struct inode *afs_root_iget(struct super_block *, struct key *);
extern bool afs_check_validity(struct afs_vnode *);
extern int afs_validate(struct afs_vnode *, struct key *);
+bool afs_pagecache_valid(struct afs_vnode *);
extern int afs_getattr(struct mnt_idmap *idmap, const struct path *,
struct kstat *, u32, unsigned int);
extern int afs_setattr(struct mnt_idmap *idmap, struct dentry *, struct iattr *);
--
2.35.1