From b514f872f86d4b0c13fed74a1fe1f7ab500c4fd0 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Wed, 16 Mar 2011 06:26:11 -0400 Subject: [PATCH] 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/internal.h | 15 ++++----- fs/nfs/namespace.c | 69 +++++++++++++++++++++++++++--------------- fs/nfs/nfs4namespace.c | 43 ++++++++++++-------------- fs/nfs/super.c | 9 +++--- 4 files changed, 74 insertions(+), 62 deletions(-) diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h index 9e5a003ccc5..f0234118d04 100644 --- a/fs/nfs/internal.h +++ b/fs/nfs/internal.h @@ -163,10 +163,10 @@ static inline void nfs_fs_proc_exit(void) /* nfs4namespace.c */ #ifdef CONFIG_NFS_V4 -extern struct vfsmount *nfs_do_refmount(const struct vfsmount *mnt_parent, struct dentry *dentry); +extern struct vfsmount *nfs_do_refmount(struct super_block *sb, struct dentry *dentry); #else static inline -struct vfsmount *nfs_do_refmount(const struct vfsmount *mnt_parent, struct dentry *dentry) +struct vfsmount *nfs_do_refmount(struct super_block *sb, struct dentry *dentry) { return ERR_PTR(-ENOENT); } @@ -247,9 +247,7 @@ extern void nfs_sb_active(struct super_block *sb); extern void nfs_sb_deactive(struct super_block *sb); /* namespace.c */ -extern char *nfs_path(const char *base, - const struct dentry *droot, - const struct dentry *dentry, +extern char *nfs_path(char **p, struct dentry *dentry, char *buffer, ssize_t buflen); extern struct vfsmount *nfs_d_automount(struct path *path); @@ -290,12 +288,11 @@ extern int _nfs4_call_sync_session(struct nfs_server *server, /* * Determine the device name as a string */ -static inline char *nfs_devname(const struct vfsmount *mnt_parent, - const struct dentry *dentry, +static inline char *nfs_devname(struct dentry *dentry, char *buffer, ssize_t buflen) { - return nfs_path(mnt_parent->mnt_devname, mnt_parent->mnt_root, - dentry, buffer, buflen); + char *dummy; + return nfs_path(&dummy, dentry, buffer, buflen); } /* diff --git a/fs/nfs/namespace.c b/fs/nfs/namespace.c index f32b8603dca..859cdaba4c1 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: diff --git a/fs/nfs/nfs4namespace.c b/fs/nfs/nfs4namespace.c index 3c2a1724fbd..46942e2680a 100644 --- a/fs/nfs/nfs4namespace.c +++ b/fs/nfs/nfs4namespace.c @@ -54,33 +54,29 @@ Elong: /* * Determine the mount path as a string */ -static char *nfs4_path(const struct vfsmount *mnt_parent, - const struct dentry *dentry, - char *buffer, ssize_t buflen) +static char *nfs4_path(struct dentry *dentry, char *buffer, ssize_t buflen) { - const char *srvpath; - - srvpath = strchr(mnt_parent->mnt_devname, ':'); - if (srvpath) - srvpath++; - else - srvpath = mnt_parent->mnt_devname; - - return nfs_path(srvpath, mnt_parent->mnt_root, dentry, buffer, buflen); + char *limit; + char *path = nfs_path(&limit, dentry, buffer, buflen); + if (!IS_ERR(path)) { + char *colon = strchr(path, ':'); + if (colon && colon < limit) + path = colon + 1; + } + return path; } /* * Check that fs_locations::fs_root [RFC3530 6.3] is a prefix for what we * believe to be the server path to this dentry */ -static int nfs4_validate_fspath(const struct vfsmount *mnt_parent, - const struct dentry *dentry, +static int nfs4_validate_fspath(struct dentry *dentry, const struct nfs4_fs_locations *locations, char *page, char *page2) { const char *path, *fs_path; - path = nfs4_path(mnt_parent, dentry, page, PAGE_SIZE); + path = nfs4_path(dentry, page, PAGE_SIZE); if (IS_ERR(path)) return PTR_ERR(path); @@ -165,20 +161,20 @@ static struct vfsmount *try_location(struct nfs_clone_mount *mountdata, /** * nfs_follow_referral - set up mountpoint when hitting a referral on moved error - * @mnt_parent - mountpoint of parent directory + * @sb - superblock of parent directory * @dentry - parent directory * @locations - array of NFSv4 server location information * */ -static struct vfsmount *nfs_follow_referral(const struct vfsmount *mnt_parent, - const struct dentry *dentry, +static struct vfsmount *nfs_follow_referral(struct super_block *sb, + struct dentry *dentry, const struct nfs4_fs_locations *locations) { struct vfsmount *mnt = ERR_PTR(-ENOENT); struct nfs_clone_mount mountdata = { - .sb = mnt_parent->mnt_sb, + .sb = sb, .dentry = dentry, - .authflavor = NFS_SB(mnt_parent->mnt_sb)->client->cl_auth->au_flavor, + .authflavor = NFS_SB(sb)->client->cl_auth->au_flavor, }; char *page = NULL, *page2 = NULL; int loc, error; @@ -198,7 +194,7 @@ static struct vfsmount *nfs_follow_referral(const struct vfsmount *mnt_parent, goto out; /* Ensure fs path is a prefix of current dentry path */ - error = nfs4_validate_fspath(mnt_parent, dentry, locations, page, page2); + error = nfs4_validate_fspath(dentry, locations, page, page2); if (error < 0) { mnt = ERR_PTR(error); goto out; @@ -225,11 +221,10 @@ out: /* * nfs_do_refmount - handle crossing a referral on server - * @mnt_parent - mountpoint of referral * @dentry - dentry of referral * */ -struct vfsmount *nfs_do_refmount(const struct vfsmount *mnt_parent, struct dentry *dentry) +struct vfsmount *nfs_do_refmount(struct super_block *sb, struct dentry *dentry) { struct vfsmount *mnt = ERR_PTR(-ENOMEM); struct dentry *parent; @@ -262,7 +257,7 @@ struct vfsmount *nfs_do_refmount(const struct vfsmount *mnt_parent, struct dentr fs_locations->fs_path.ncomponents <= 0) goto out_free; - mnt = nfs_follow_referral(mnt_parent, dentry, fs_locations); + mnt = nfs_follow_referral(sb, dentry, fs_locations); out_free: __free_page(page); kfree(fs_locations); diff --git a/fs/nfs/super.c b/fs/nfs/super.c index 1d81032b226..a6ab483c9ad 100644 --- a/fs/nfs/super.c +++ b/fs/nfs/super.c @@ -2771,16 +2771,15 @@ static struct vfsmount *nfs_do_root_mount(struct file_system_type *fs_type, return root_mnt; } -static void nfs_fix_devname(const struct path *path, struct vfsmount *mnt) +static void nfs_fix_devname(struct dentry *dentry, struct vfsmount *mnt) { char *page = (char *) __get_free_page(GFP_KERNEL); char *devname, *tmp; + char *dummy; if (page == NULL) return; - devname = nfs_path(path->mnt->mnt_devname, - path->mnt->mnt_root, path->dentry, - page, PAGE_SIZE); + devname = nfs_path(&dummy, dentry, page, PAGE_SIZE); if (IS_ERR(devname)) goto out_freepage; tmp = kstrdup(devname, GFP_KERNEL); @@ -2894,7 +2893,7 @@ static int nfs_follow_remote_path(struct vfsmount *root_mnt, mnt_target->mnt_root = dget(nd->path.dentry); /* Correct the device pathname */ - nfs_fix_devname(&nd->path, mnt_target); + nfs_fix_devname(nd->path.dentry, mnt_target); path_put(&nd->path); kfree(nd); -- 2.20.1