[PATCH v3 18/19] afs: Fix afs_get_link() to take validate_lock around afs_read_single()
David Howells <[email protected]>
| Newsgroups | dev.linux.lists.netfs,org.kernel.vger.ceph-devel,org.kernel.vger.linux-cifs,org.kernel.vger.linux-fsdevel,org.kernel.vger.linux-kernel |
|---|---|
| Message-ID | <[email protected]> |
Fix afs_get_link() to take the validate_lock around afs_read_single() to
prevent races between multiple ->get_link() calls.
Fixes: eae9e78951bb ("afs: Use netfslib for symlinks, allowing them to be cached")
Closes: https://sashiko.dev/#/patchset/20260326104544.509518-1-dhowells%40redhat.com
Signed-off-by: David Howells <[email protected]>
cc: Marc Dionne <[email protected]>
cc: [email protected]
cc: [email protected]
---
fs/afs/inode.c | 17 +++++++++++++----
1 file changed, 13 insertions(+), 4 deletions(-)
diff --git a/fs/afs/inode.c b/fs/afs/inode.c
index 06e25e1b12df..5207c4a003f6 100644
--- a/fs/afs/inode.c
+++ b/fs/afs/inode.c
@@ -78,10 +78,19 @@ const char *afs_get_link(struct dentry *dentry, struct inode *inode,
goto good;
fetch:
- ret = afs_read_single(vnode, NULL);
- if (ret < 0)
- return ERR_PTR(ret);
- set_bit(AFS_VNODE_DIR_READ, &vnode->flags);
+ if (down_write_killable(&vnode->validate_lock) < 0)
+ return ERR_PTR(-ERESTARTSYS);
+ if (test_and_clear_bit(AFS_VNODE_ZAP_DATA, &vnode->flags) ||
+ !test_bit(AFS_VNODE_DIR_READ, &vnode->flags)) {
+ ret = afs_read_single(vnode, NULL);
+ if (ret < 0) {
+ up_write(&vnode->validate_lock);
+ return ERR_PTR(ret);
+ }
+ set_bit(AFS_VNODE_DIR_READ, &vnode->flags);
+ }
+
+ up_write(&vnode->validate_lock);
good:
folio = folioq_folio(vnode->directory, 0);