afs: split afs_pagecache_valid() out of afs_validate()

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.

Link: https://lkml.kernel.org/r/20230327174515.1811532-3-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: David Howells <dhowells@redhat.com>
Tested-by: David Howells <dhowells@redhat.com>
Cc: Darrick J. Wong <djwong@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/fs/afs/file.c b/fs/afs/file.c
index 68d6d5d..719b313 100644 (file)
--- 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 0167e96..b1bdffd 100644 (file)
--- 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 ad8523d..5c95df6 100644 (file)
--- 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 *);