From b514f872f86d4b0c13fed74a1fe1f7ab500c4fd0 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Wed, 16 Mar 2011 06:26:11 -0400 Subject: nfs: make nfs_path() work without vfsmount part 3: now we have everything to get nfs_path() just by dentry - just follow to (disconnected) root and pick the rest of the thing there. Start killing propagation of struct vfsmount * on the paths that used to bring it to nfs_path(). Signed-off-by: Al Viro --- fs/nfs/namespace.c | 69 +++++++++++++++++++++++++++++++++++------------------- 1 file changed, 45 insertions(+), 24 deletions(-) (limited to 'fs/nfs/namespace.c') diff --git a/fs/nfs/namespace.c b/fs/nfs/namespace.c index f32b8603dca8..859cdaba4c1c 100644 --- a/fs/nfs/namespace.c +++ b/fs/nfs/namespace.c @@ -25,33 +25,31 @@ static LIST_HEAD(nfs_automount_list); static DECLARE_DELAYED_WORK(nfs_automount_task, nfs_expire_automounts); int nfs_mountpoint_expiry_timeout = 500 * HZ; -static struct vfsmount *nfs_do_submount(const struct vfsmount *mnt_parent, - const struct dentry *dentry, +static struct vfsmount *nfs_do_submount(struct super_block *sb, + struct dentry *dentry, struct nfs_fh *fh, struct nfs_fattr *fattr); /* * nfs_path - reconstruct the path given an arbitrary dentry - * @base - arbitrary string to prepend to the path - * @droot - pointer to root dentry for mountpoint + * @base - used to return pointer to the end of devname part of path * @dentry - pointer to dentry * @buffer - result buffer * @buflen - length of buffer * - * Helper function for constructing the path from the - * root dentry to an arbitrary hashed dentry. + * Helper function for constructing the server pathname + * by arbitrary hashed dentry. * * This is mainly for use in figuring out the path on the - * server side when automounting on top of an existing partition. + * server side when automounting on top of an existing partition + * and in generating /proc/mounts and friends. */ -char *nfs_path(const char *base, - const struct dentry *droot, - const struct dentry *dentry, - char *buffer, ssize_t buflen) +char *nfs_path(char **p, struct dentry *dentry, char *buffer, ssize_t buflen) { char *end; int namelen; unsigned seq; + const char *base; rename_retry: end = buffer+buflen; @@ -60,7 +58,10 @@ rename_retry: seq = read_seqbegin(&rename_lock); rcu_read_lock(); - while (!IS_ROOT(dentry) && dentry != droot) { + while (1) { + spin_lock(&dentry->d_lock); + if (IS_ROOT(dentry)) + break; namelen = dentry->d_name.len; buflen -= namelen + 1; if (buflen < 0) @@ -68,27 +69,47 @@ rename_retry: end -= namelen; memcpy(end, dentry->d_name.name, namelen); *--end = '/'; + spin_unlock(&dentry->d_lock); dentry = dentry->d_parent; } - rcu_read_unlock(); - if (read_seqretry(&rename_lock, seq)) + if (read_seqretry(&rename_lock, seq)) { + spin_unlock(&dentry->d_lock); + rcu_read_unlock(); goto rename_retry; + } if (*end != '/') { - if (--buflen < 0) + if (--buflen < 0) { + spin_unlock(&dentry->d_lock); + rcu_read_unlock(); goto Elong; + } *--end = '/'; } + *p = end; + base = dentry->d_fsdata; + if (!base) { + spin_unlock(&dentry->d_lock); + rcu_read_unlock(); + WARN_ON(1); + return end; + } namelen = strlen(base); /* Strip off excess slashes in base string */ while (namelen > 0 && base[namelen - 1] == '/') namelen--; buflen -= namelen; - if (buflen < 0) + if (buflen < 0) { + spin_lock(&dentry->d_lock); + rcu_read_unlock(); goto Elong; + } end -= namelen; memcpy(end, base, namelen); + spin_unlock(&dentry->d_lock); + rcu_read_unlock(); return end; Elong_unlock: + spin_lock(&dentry->d_lock); rcu_read_unlock(); if (read_seqretry(&rename_lock, seq)) goto rename_retry; @@ -143,9 +164,9 @@ struct vfsmount *nfs_d_automount(struct path *path) } if (fattr->valid & NFS_ATTR_FATTR_V4_REFERRAL) - mnt = nfs_do_refmount(path->mnt, path->dentry); + mnt = nfs_do_refmount(path->mnt->mnt_sb, path->dentry); else - mnt = nfs_do_submount(path->mnt, path->dentry, fh, fattr); + mnt = nfs_do_submount(path->mnt->mnt_sb, path->dentry, fh, fattr); if (IS_ERR(mnt)) goto out; @@ -209,19 +230,19 @@ static struct vfsmount *nfs_do_clone_mount(struct nfs_server *server, /** * nfs_do_submount - set up mountpoint when crossing a filesystem boundary - * @mnt_parent - mountpoint of parent directory + * @sb - superblock of parent directory * @dentry - parent directory * @fh - filehandle for new root dentry * @fattr - attributes for new root inode * */ -static struct vfsmount *nfs_do_submount(const struct vfsmount *mnt_parent, - const struct dentry *dentry, +static struct vfsmount *nfs_do_submount(struct super_block *sb, + struct dentry *dentry, struct nfs_fh *fh, struct nfs_fattr *fattr) { struct nfs_clone_mount mountdata = { - .sb = mnt_parent->mnt_sb, + .sb = sb, .dentry = dentry, .fh = fh, .fattr = fattr, @@ -237,11 +258,11 @@ static struct vfsmount *nfs_do_submount(const struct vfsmount *mnt_parent, dentry->d_name.name); if (page == NULL) goto out; - devname = nfs_devname(mnt_parent, dentry, page, PAGE_SIZE); + devname = nfs_devname(dentry, page, PAGE_SIZE); mnt = (struct vfsmount *)devname; if (IS_ERR(devname)) goto free_page; - mnt = nfs_do_clone_mount(NFS_SB(mnt_parent->mnt_sb), devname, &mountdata); + mnt = nfs_do_clone_mount(NFS_SB(sb), devname, &mountdata); free_page: free_page((unsigned long)page); out: -- cgit v1.2.3-59-g8ed1b