Messages in this thread | | | Subject | Re: [PATCH 2/2] fix up new filp allocators | From | Dave Hansen <> | Date | Fri, 09 Nov 2007 13:35:22 -0800 |
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On Fri, 2007-11-09 at 16:26 -0500, Trond Myklebust wrote: > > #include <linux/sunrpc/svc.h> > > #include <linux/nfsd/nfsd.h> > > #include <linux/nfsd/cache.h> > > +#include <linux/file.h> > > #include <linux/mount.h> > > #include <linux/workqueue.h> > > #include <linux/smp_lock.h> > > @@ -1303,7 +1304,7 @@ static inline void > > nfs4_file_downgrade(struct file *filp, unsigned int share_access) > > { > > if (share_access & NFS4_SHARE_ACCESS_WRITE) { > > - put_write_access(filp->f_path.dentry->d_inode); > > + drop_file_write_access(filp); > > filp->f_mode = (filp->f_mode | FMODE_READ) & ~FMODE_WRITE; > > } > > } > > Hmm... The NFS server may also try to 'upgrade' an open file request to > a read/write request whenever the client issues a new OPEN request for > WRITE using the same open_owner.
Can you point me to some code? I'll try and go fix it up.
> > diff -puN fs/pipe.c~fix-idmapd-bug fs/pipe.c > > --- linux-2.6.git/fs/pipe.c~fix-idmapd-bug 2007-11-09 12:13:15.000000000 -0800 > > +++ linux-2.6.git-dave/fs/pipe.c 2007-11-09 12:13:15.000000000 -0800 > > @@ -959,13 +959,10 @@ struct file *create_write_pipe(void) > > struct dentry *dentry; > > struct qstr name = { .name = "" }; > > > > - f = get_empty_filp(); > > - if (!f) > > - return ERR_PTR(-ENFILE); > > err = -ENFILE; > > inode = get_pipe_inode(); > > if (!inode) > > - goto err_file; > > + goto err; > > > > err = -ENOMEM; > > dentry = d_alloc(pipe_mnt->mnt_sb->s_root, &name); > > @@ -980,13 +977,14 @@ struct file *create_write_pipe(void) > > */ > > dentry->d_flags &= ~DCACHE_UNHASHED; > > d_instantiate(dentry, inode); > > - f->f_path.mnt = mntget(pipe_mnt); > > - f->f_path.dentry = dentry; > > + > > + f = alloc_file(pipe_mnt, dentry, FMODE_WRITE, &write_pipe_fops); > > + err = -ENFILE; > > + if (!f) > > + goto err_inode; > > f->f_mapping = inode->i_mapping; > > > > f->f_flags = O_WRONLY; > > - f->f_op = &write_pipe_fops; > > - f->f_mode = FMODE_WRITE; > > f->f_version = 0; > > > > return f; > > @@ -994,8 +992,7 @@ struct file *create_write_pipe(void) > > err_inode: > > free_pipe_info(inode); > > iput(inode); > > - err_file: > > - put_filp(f); > > + err: > > return ERR_PTR(err); > > } > > Does RPC idmapd open a regular pipe too? I thought it only used > rpc_pipefs?
No. I the the actual bug triggered by idmapd was from an eventpoll filp that had been acquired through anon_inode_getfd(). I just noticed the pipe code here could be another potential bug of the same type.
-- Dave
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