From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx2.suse.de ([195.135.220.15]:48716 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753103AbeFGB7A (ORCPT ); Wed, 6 Jun 2018 21:59:00 -0400 Subject: Re: [PATCH 26/32] afs: Use fs_context to pass parameters over automount [ver #8] To: David Howells , viro@zeniv.linux.org.uk Cc: linux-fsdevel@vger.kernel.org, linux-afs@lists.infradead.org, linux-kernel@vger.kernel.org References: <152720672288.9073.9868393448836301272.stgit@warthog.procyon.org.uk> <152720689245.9073.17300569813645143102.stgit@warthog.procyon.org.uk> From: Goldwyn Rodrigues Message-ID: <1917614e-97dc-c911-c2d1-cc5d002d2071@suse.de> Date: Wed, 6 Jun 2018 20:58:56 -0500 MIME-Version: 1.0 In-Reply-To: <152720689245.9073.17300569813645143102.stgit@warthog.procyon.org.uk> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On 05/24/2018 07:08 PM, David Howells wrote: > Alter the AFS automounting code to create and modify an fs_context struct > when parameterising a new mount triggered by an AFS mountpoint rather than > constructing device name and option strings. > > Also remove the cell=, vol= and rwpath options as they are then redundant. > The reason they existed is because the 'device name' may be derived > literally from a mountpoint object in the filesystem, so default cell and > parent-type information needed to be passed in by some other method from > the automount routines. The vol= option didn't end up being used. > > Signed-off-by: David Howells > cc: Eric W. Biederman > --- > > fs/afs/internal.h | 1 > fs/afs/mntpt.c | 148 +++++++++++++++++++++++++++-------------------------- > fs/afs/super.c | 43 +-------------- > 3 files changed, 79 insertions(+), 113 deletions(-) > > diff --git a/fs/afs/internal.h b/fs/afs/internal.h > index eb6e75e00181..90af5001f8c8 100644 > --- a/fs/afs/internal.h > +++ b/fs/afs/internal.h > @@ -35,7 +35,6 @@ struct pagevec; > struct afs_call; > > struct afs_fs_context { > - bool rwpath; /* T if the parent should be considered R/W */ > bool force; /* T to force cell type */ > bool autocell; /* T if set auto mount operation */ > bool dyn_root; /* T if dynamic root */ > diff --git a/fs/afs/mntpt.c b/fs/afs/mntpt.c > index c45aa1776591..fc383d727552 100644 > --- a/fs/afs/mntpt.c > +++ b/fs/afs/mntpt.c > @@ -47,6 +47,8 @@ static DECLARE_DELAYED_WORK(afs_mntpt_expiry_timer, afs_mntpt_expiry_timed_out); > > static unsigned long afs_mntpt_expiry_timeout = 10 * 60; > > +static const char afs_root_volume[] = "root.cell"; > + > /* > * no valid lookup procedure on this sort of dir > */ > @@ -68,107 +70,107 @@ static int afs_mntpt_open(struct inode *inode, struct file *file) > } > > /* > - * create a vfsmount to be automounted > + * Set the parameters for the proposed superblock. > */ > -static struct vfsmount *afs_mntpt_do_automount(struct dentry *mntpt) > +static int afs_mntpt_set_params(struct fs_context *fc, struct dentry *mntpt) > { > - struct afs_super_info *as; > - struct vfsmount *mnt; > - struct afs_vnode *vnode; > - struct page *page; > - char *devname, *options; > - bool rwpath = false; > + struct afs_fs_context *ctx = fc->fs_private; > + struct afs_vnode *vnode = AFS_FS_I(d_inode(mntpt)); > + struct afs_cell *cell; > + const char *p; > int ret; > > - _enter("{%pd}", mntpt); > - > - BUG_ON(!d_inode(mntpt)); > - > - ret = -ENOMEM; > - devname = (char *) get_zeroed_page(GFP_KERNEL); > - if (!devname) > - goto error_no_devname; > - > - options = (char *) get_zeroed_page(GFP_KERNEL); > - if (!options) > - goto error_no_options; > - > - vnode = AFS_FS_I(d_inode(mntpt)); > if (test_bit(AFS_VNODE_PSEUDODIR, &vnode->flags)) { > /* if the directory is a pseudo directory, use the d_name */ > - static const char afs_root_cell[] = ":root.cell."; > unsigned size = mntpt->d_name.len; > > - ret = -ENOENT; > - if (size < 2 || size > AFS_MAXCELLNAME) > - goto error_no_page; > + if (size < 2) > + return -ENOENT; > > + p = mntpt->d_name.name; > if (mntpt->d_name.name[0] == '.') { > - devname[0] = '%'; > - memcpy(devname + 1, mntpt->d_name.name + 1, size - 1); > - memcpy(devname + size, afs_root_cell, > - sizeof(afs_root_cell)); > - rwpath = true; > - } else { > - devname[0] = '#'; > - memcpy(devname + 1, mntpt->d_name.name, size); > - memcpy(devname + size + 1, afs_root_cell, > - sizeof(afs_root_cell)); > + size--; > + p++; > + ctx->type = AFSVL_RWVOL; > + ctx->force = true; > + } > + if (size > AFS_MAXCELLNAME) > + return -ENAMETOOLONG; > + > + cell = afs_lookup_cell(ctx->net, p, size, NULL, false); > + if (IS_ERR(cell)) { > + pr_err("kAFS: unable to lookup cell '%pd'\n", mntpt); > + return PTR_ERR(cell); > } > + afs_put_cell(ctx->net, ctx->cell); > + ctx->cell = cell; > + > + ctx->volname = afs_root_volume; > + ctx->volnamesz = sizeof(afs_root_volume) - 1; > } else { > /* read the contents of the AFS special symlink */ > + struct page *page; > loff_t size = i_size_read(d_inode(mntpt)); > char *buf; > > - ret = -EINVAL; > if (size > PAGE_SIZE - 1) > - goto error_no_page; > + return -EINVAL; > > page = read_mapping_page(d_inode(mntpt)->i_mapping, 0, NULL); > - if (IS_ERR(page)) { > - ret = PTR_ERR(page); > - goto error_no_page; > - } > + if (IS_ERR(page)) > + return PTR_ERR(page); > > - ret = -EIO; > - if (PageError(page)) > - goto error; > + if (PageError(page)) { > + put_page(page); > + return -EIO; > + } > > - buf = kmap_atomic(page); > - memcpy(devname, buf, size); > - kunmap_atomic(buf); > + buf = kmap(page); > + ret = vfs_set_fs_source(fc, buf, size); > + kunmap(page); > put_page(page); > - page = NULL; > + if (ret < 0) > + return ret; > } > > - /* work out what options we want */ > - as = AFS_FS_S(mntpt->d_sb); > - if (as->cell) { > - memcpy(options, "cell=", 5); > - strcpy(options + 5, as->cell->name); > - if ((as->volume && as->volume->type == AFSVL_RWVOL) || rwpath) > - strcat(options, ",rwpath"); > - } > + return 0; > +} > > - /* try and do the mount */ > - _debug("--- attempting mount %s -o %s ---", devname, options); > - mnt = vfs_submount(mntpt, &afs_fs_type, devname, > - options, strlen(options) + 1); > - _debug("--- mount result %p ---", mnt); > +/* > + * create a vfsmount to be automounted > + */ > +static struct vfsmount *afs_mntpt_do_automount(struct dentry *mntpt) > +{ > + struct fs_context *fc; > + struct vfsmount *mnt; > + int ret; > + > + BUG_ON(!d_inode(mntpt)); > + > + fc = vfs_new_fs_context(&afs_fs_type, mntpt, 0, > + FS_CONTEXT_FOR_SUBMOUNT); > + if (IS_ERR(fc)) > + return ERR_CAST(fc); > + > + ret = afs_mntpt_set_params(fc, mntpt); > + if (ret < 0) > + goto error_fc; > + > + ret = vfs_get_tree(fc); > + if (ret < 0) > + goto error_fc; > + > + mnt = vfs_create_mount(fc, 0); > + if (IS_ERR(mnt)) { > + ret = PTR_ERR(mnt); > + goto error_fc; > + } > > - free_page((unsigned long) devname); > - free_page((unsigned long) options); > - _leave(" = %p", mnt); > + put_fs_context(fc); > return mnt; > Why are you performing a put_fs_context(fc) in the success code path? Do we not need a reference of fc anymore? > -error: > - put_page(page); > -error_no_page: > - free_page((unsigned long) options); > -error_no_options: > - free_page((unsigned long) devname); > -error_no_devname: > - _leave(" = %d", ret); > +error_fc: > + put_fs_context(fc); > return ERR_PTR(ret); > } > -- Goldwyn