From 63d49d843ef5fffeea069e0ffdfbd2bf40ba01c6 Mon Sep 17 00:00:00 2001 From: David Howells Date: Wed, 1 Sep 2021 18:11:33 +0100 Subject: afs: Fix incorrect triggering of sillyrename on 3rd-party invalidation The AFS filesystem is currently triggering the silly-rename cleanup from afs_d_revalidate() when it sees that a dentry has been changed by a third party[1]. It should not be doing this as the cleanup includes deleting the silly-rename target file on iput. Fix this by removing the places in the d_revalidate handling that validate anything other than the directory and the dirent. It probably should not be looking to validate the target inode of the dentry also. This includes removing the point in afs_d_revalidate() where the inode that a dentry used to point to was marked as being deleted (AFS_VNODE_DELETED). We don't know it got deleted. It could have been renamed or it could have hard links remaining. This was reproduced by cloning a git repo onto an afs volume on one machine, switching to another machine and doing "git status", then switching back to the first and doing "git status". The second status would show weird output due to ".git/index" getting deleted by the above mentioned mechanism. A simpler way to do it is to do: machine 1: touch a machine 2: touch b; mv -f b a machine 1: stat a on an afs volume. The bug shows up as the stat failing with ENOENT and the file server log showing that machine 1 deleted "a". Fixes: 79ddbfa500b3 ("afs: Implement sillyrename for unlink and rename") Reported-by: Markus Suvanto Signed-off-by: David Howells Tested-by: Markus Suvanto cc: linux-afs@lists.infradead.org Link: https://bugzilla.kernel.org/show_bug.cgi?id=214217#c4 [1] Link: https://lore.kernel.org/r/163111668100.283156.3851669884664475428.stgit@warthog.procyon.org.uk/ --- fs/afs/dir.c | 46 +++++++--------------------------------------- 1 file changed, 7 insertions(+), 39 deletions(-) (limited to 'fs/afs') diff --git a/fs/afs/dir.c b/fs/afs/dir.c index a8e3ae55f1f9..4579bbda4634 100644 --- a/fs/afs/dir.c +++ b/fs/afs/dir.c @@ -1077,9 +1077,9 @@ static struct dentry *afs_lookup(struct inode *dir, struct dentry *dentry, */ static int afs_d_revalidate_rcu(struct dentry *dentry) { - struct afs_vnode *dvnode, *vnode; + struct afs_vnode *dvnode; struct dentry *parent; - struct inode *dir, *inode; + struct inode *dir; long dir_version, de_version; _enter("%p", dentry); @@ -1109,18 +1109,6 @@ static int afs_d_revalidate_rcu(struct dentry *dentry) return -ECHILD; } - /* Check to see if the vnode referred to by the dentry still - * has a callback. - */ - if (d_really_is_positive(dentry)) { - inode = d_inode_rcu(dentry); - if (inode) { - vnode = AFS_FS_I(inode); - if (!afs_check_validity(vnode)) - return -ECHILD; - } - } - return 1; /* Still valid */ } @@ -1156,17 +1144,7 @@ static int afs_d_revalidate(struct dentry *dentry, unsigned int flags) if (IS_ERR(key)) key = NULL; - if (d_really_is_positive(dentry)) { - inode = d_inode(dentry); - if (inode) { - vnode = AFS_FS_I(inode); - afs_validate(vnode, key); - if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) - goto out_bad; - } - } - - /* lock down the parent dentry so we can peer at it */ + /* Hold the parent dentry so we can peer at it */ parent = dget_parent(dentry); dir = AFS_FS_I(d_inode(parent)); @@ -1175,7 +1153,7 @@ static int afs_d_revalidate(struct dentry *dentry, unsigned int flags) if (test_bit(AFS_VNODE_DELETED, &dir->flags)) { _debug("%pd: parent dir deleted", dentry); - goto out_bad_parent; + goto not_found; } /* We only need to invalidate a dentry if the server's copy changed @@ -1201,12 +1179,12 @@ static int afs_d_revalidate(struct dentry *dentry, unsigned int flags) case 0: /* the filename maps to something */ if (d_really_is_negative(dentry)) - goto out_bad_parent; + goto not_found; inode = d_inode(dentry); if (is_bad_inode(inode)) { printk("kAFS: afs_d_revalidate: %pd2 has bad inode\n", dentry); - goto out_bad_parent; + goto not_found; } vnode = AFS_FS_I(inode); @@ -1228,9 +1206,6 @@ static int afs_d_revalidate(struct dentry *dentry, unsigned int flags) dentry, fid.unique, vnode->fid.unique, vnode->vfs_inode.i_generation); - write_seqlock(&vnode->cb_lock); - set_bit(AFS_VNODE_DELETED, &vnode->flags); - write_sequnlock(&vnode->cb_lock); goto not_found; } goto out_valid; @@ -1245,7 +1220,7 @@ static int afs_d_revalidate(struct dentry *dentry, unsigned int flags) default: _debug("failed to iterate dir %pd: %d", parent, ret); - goto out_bad_parent; + goto not_found; } out_valid: @@ -1256,16 +1231,9 @@ out_valid_noupdate: _leave(" = 1 [valid]"); return 1; - /* the dirent, if it exists, now points to a different vnode */ not_found: - spin_lock(&dentry->d_lock); - dentry->d_flags |= DCACHE_NFSFS_RENAMED; - spin_unlock(&dentry->d_lock); - -out_bad_parent: _debug("dropping dentry %pd2", dentry); dput(parent); -out_bad: key_put(key); _leave(" = 0 [bad]"); -- cgit v1.2.3