Messages in this thread Patches in this message |  | | Date | Wed, 11 Jun 2003 00:22:26 -0700 | From | Frank Cusack <> | Subject | [PATCH] NFS sillyrename fixes (was: [PATCH] nfs_unlink() race) |
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On Wed, Jun 11, 2003 at 04:00:41AM +0100, viro@parcelfarce.linux.theplanet.co.uk wrote: > FWIW, we could probably simply do the following: have nfs_lookup() > return ERR_PTR(-EINVAL) if it notices that it's about to give us > such alias. IOW, no access to such guys at all - if it's going > to die, we refuse to do anything with it. I'll try to do that > variant when I get some sleep - I'd rather not mess with anything > in that area until I'm completely awake...
Sounds ok to me, except that Linus says
On Tue, Jun 10, 2003 at 10:30:10PM -0700, Linus Torvalds wrote: > > On Wed, 11 Jun 2003 viro@parcelfarce.linux.theplanet.co.uk wrote: > > > > Two different dentries for the same file is obviously not a problem... > > It _is_ a problem. It does the wrong thing on any subsequent directory > operation (move or unlink). > > Multiple aliased dentries have never been ok, unless the filesystem > explicitly handles them and invalidates them (ie ntfs/fat kind of things).
so anyway, please find attached a 2.4.21-rc7 and 2.5.70 patch which prevents removal or rename of unlinked-but-open files. You can see the rename bug by doing something like
mkdir d1 d2 hold a file open in d1 and rm it; it gets sillyrenamed move sillyrenamed file to d2 rmdir d1 close file => "inode number mismatch" (data->dir isn't "live", ie it doesn't follow the rename, and d1 is gone)
/fc --- linux-2.4.21-rc7/fs/namei.c Sun Jun 8 23:57:33 2003 +++ linux-2.4.21-rc7-silly/fs/namei.c Tue Jun 10 23:49:08 2003 @@ -1482,13 +1482,14 @@ int vfs_unlink(struct inode *dir, struct lock_kernel(); error = dir->i_op->unlink(dir, dentry); unlock_kernel(); - if (!error) + if (!error && + !(dentry->d_flags & DCACHE_NFSFS_RENAMED)) d_delete(dentry); } } } up(&dir->i_zombie); - if (!error) + if (!error && !(dentry->d_flags & DCACHE_NFSFS_RENAMED)) inode_dir_notify(dir, DN_DELETE); return error; } @@ -1830,6 +1831,10 @@ int vfs_rename(struct inode *old_dir, st struct inode *new_dir, struct dentry *new_dentry) { int error; + + if (old_dentry->d_flags & DCACHE_NFSFS_RENAMED) + return -EBUSY; + if (S_ISDIR(old_dentry->d_inode->i_mode)) error = vfs_rename_dir(old_dir,old_dentry,new_dir,new_dentry); else--- linux-2.5.70/fs/namei.c Sun Jun 1 23:30:30 2003 +++ linux-2.5.70-silly/fs/namei.c Tue Jun 10 23:44:14 2003 @@ -1631,7 +1631,9 @@ int vfs_unlink(struct inode *dir, struct error = dir->i_op->unlink(dir, dentry); } up(&dentry->d_inode->i_sem); - if (!error) { + + /* We don't d_delete() NFS sillyrenamed files--they still exist. */ + if (!error && !(dentry->d_flags & DCACHE_NFSFS_RENAMED)) { d_delete(dentry); inode_dir_notify(dir, DN_DELETE); } @@ -1949,6 +1951,10 @@ int vfs_rename(struct inode *old_dir, st if (old_dentry->d_inode == new_dentry->d_inode) return 0; + + /* Don't allow sillyrenamed files to move; messes up async_unlink */ + if (old_dentry->d_flags & DCACHE_NFSFS_RENAMED) + return -EBUSY; error = may_delete(old_dir, old_dentry, is_dir); if (error) |  |