From 35759521eedf60ce7d3127c5d33953cd2d1bd35f Mon Sep 17 00:00:00 2001 From: Al Viro Date: Sun, 8 Sep 2013 13:41:33 -0400 Subject: take unlazy_walk() into umount_lookup_last() ... and massage it a bit to reduce nesting Signed-off-by: Al Viro --- fs/namei.c | 60 +++++++++++++++++++++++++++--------------------------------- 1 file changed, 27 insertions(+), 33 deletions(-) (limited to 'fs/namei.c') diff --git a/fs/namei.c b/fs/namei.c index f415c6683a83..0ab9e6756f3d 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -2256,19 +2256,22 @@ umount_lookup_last(struct nameidata *nd, struct path *path) struct dentry *dentry; struct dentry *dir = nd->path.dentry; - if (unlikely(nd->flags & LOOKUP_RCU)) { - WARN_ON_ONCE(1); - error = -ECHILD; - goto error_check; + /* If we're in rcuwalk, drop out of it to handle last component */ + if (nd->flags & LOOKUP_RCU) { + if (unlazy_walk(nd, NULL)) { + error = -ECHILD; + goto out; + } } nd->flags &= ~LOOKUP_PARENT; if (unlikely(nd->last_type != LAST_NORM)) { error = handle_dots(nd, nd->last_type); - if (!error) - dentry = dget(nd->path.dentry); - goto error_check; + if (error) + goto out; + dentry = dget(nd->path.dentry); + goto done; } mutex_lock(&dir->d_inode->i_mutex); @@ -2282,28 +2285,28 @@ umount_lookup_last(struct nameidata *nd, struct path *path) dentry = d_alloc(dir, &nd->last); if (!dentry) { error = -ENOMEM; - } else { - dentry = lookup_real(dir->d_inode, dentry, nd->flags); - if (IS_ERR(dentry)) - error = PTR_ERR(dentry); + goto out; } + dentry = lookup_real(dir->d_inode, dentry, nd->flags); + error = PTR_ERR(dentry); + if (IS_ERR(dentry)) + goto out; } mutex_unlock(&dir->d_inode->i_mutex); -error_check: - if (!error) { - if (!dentry->d_inode) { - error = -ENOENT; - dput(dentry); - } else { - path->dentry = dentry; - path->mnt = mntget(nd->path.mnt); - if (should_follow_link(dentry->d_inode, - nd->flags & LOOKUP_FOLLOW)) - return 1; - follow_mount(path); - } +done: + if (!dentry->d_inode) { + error = -ENOENT; + dput(dentry); + goto out; } + path->dentry = dentry; + path->mnt = mntget(nd->path.mnt); + if (should_follow_link(dentry->d_inode, nd->flags & LOOKUP_FOLLOW)) + return 1; + follow_mount(path); + error = 0; +out: terminate_walk(nd); return error; } @@ -2334,15 +2337,6 @@ path_umountat(int dfd, const char *name, struct path *path, unsigned int flags) if (err) goto out; - /* If we're in rcuwalk, drop out of it to handle last component */ - if (nd.flags & LOOKUP_RCU) { - err = unlazy_walk(&nd, NULL); - if (err) { - terminate_walk(&nd); - goto out; - } - } - err = umount_lookup_last(&nd, path); while (err > 0) { void *cookie; -- cgit v1.2.3 From 197df04c749a07616621b762e699b1fff4102fac Mon Sep 17 00:00:00 2001 From: Al Viro Date: Sun, 8 Sep 2013 14:03:27 -0400 Subject: rename user_path_umountat() to user_path_mountpoint_at() ... and move the extern from linux/namei.h to fs/internal.h, along with that of vfs_path_lookup(). Signed-off-by: Al Viro --- fs/internal.h | 3 +++ fs/namei.c | 23 +++++++++++------------ fs/namespace.c | 2 +- include/linux/namei.h | 3 --- 4 files changed, 15 insertions(+), 16 deletions(-) (limited to 'fs/namei.c') diff --git a/fs/internal.h b/fs/internal.h index d20893795526..2be46ea5dd0b 100644 --- a/fs/internal.h +++ b/fs/internal.h @@ -45,6 +45,9 @@ extern void __init chrdev_init(void); * namei.c */ extern int __inode_permission(struct inode *, int); +extern int user_path_mountpoint_at(int, const char __user *, unsigned int, struct path *); +extern int vfs_path_lookup(struct dentry *, struct vfsmount *, + const char *, unsigned int, struct path *); /* * namespace.c diff --git a/fs/namei.c b/fs/namei.c index 0ab9e6756f3d..11184df3307e 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -2223,7 +2223,7 @@ user_path_parent(int dfd, const char __user *path, struct nameidata *nd, } /** - * umount_lookup_last - look up last component for umount + * mountpoint_last - look up last component for umount * @nd: pathwalk nameidata - currently pointing at parent directory of "last" * @path: pointer to container for result * @@ -2250,7 +2250,7 @@ user_path_parent(int dfd, const char __user *path, struct nameidata *nd, * to the link, and nd->path will *not* be put. */ static int -umount_lookup_last(struct nameidata *nd, struct path *path) +mountpoint_last(struct nameidata *nd, struct path *path) { int error = 0; struct dentry *dentry; @@ -2312,17 +2312,16 @@ out: } /** - * path_umountat - look up a path to be umounted + * path_mountpoint - look up a path to be umounted * @dfd: directory file descriptor to start walk from * @name: full pathname to walk * @flags: lookup flags - * @nd: pathwalk nameidata * * Look up the given name, but don't attempt to revalidate the last component. * Returns 0 and "path" will be valid on success; Retuns error otherwise. */ static int -path_umountat(int dfd, const char *name, struct path *path, unsigned int flags) +path_mountpoint(int dfd, const char *name, struct path *path, unsigned int flags) { struct file *base = NULL; struct nameidata nd; @@ -2337,7 +2336,7 @@ path_umountat(int dfd, const char *name, struct path *path, unsigned int flags) if (err) goto out; - err = umount_lookup_last(&nd, path); + err = mountpoint_last(&nd, path); while (err > 0) { void *cookie; struct path link = *path; @@ -2348,7 +2347,7 @@ path_umountat(int dfd, const char *name, struct path *path, unsigned int flags) err = follow_link(&link, &nd, &cookie); if (err) break; - err = umount_lookup_last(&nd, path); + err = mountpoint_last(&nd, path); put_link(&nd, &link, cookie); } out: @@ -2362,7 +2361,7 @@ out: } /** - * user_path_umountat - lookup a path from userland in order to umount it + * user_path_mountpoint_at - lookup a path from userland in order to umount it * @dfd: directory file descriptor * @name: pathname from userland * @flags: lookup flags @@ -2376,7 +2375,7 @@ out: * Returns 0 and populates "path" on success. */ int -user_path_umountat(int dfd, const char __user *name, unsigned int flags, +user_path_mountpoint_at(int dfd, const char __user *name, unsigned int flags, struct path *path) { struct filename *s = getname(name); @@ -2385,11 +2384,11 @@ user_path_umountat(int dfd, const char __user *name, unsigned int flags, if (IS_ERR(s)) return PTR_ERR(s); - error = path_umountat(dfd, s->name, path, flags | LOOKUP_RCU); + error = path_mountpoint(dfd, s->name, path, flags | LOOKUP_RCU); if (unlikely(error == -ECHILD)) - error = path_umountat(dfd, s->name, path, flags); + error = path_mountpoint(dfd, s->name, path, flags); if (unlikely(error == -ESTALE)) - error = path_umountat(dfd, s->name, path, flags | LOOKUP_REVAL); + error = path_mountpoint(dfd, s->name, path, flags | LOOKUP_REVAL); if (likely(!error)) audit_inode(s, path->dentry, 0); diff --git a/fs/namespace.c b/fs/namespace.c index fc2b5226278d..25845d1b300b 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -1321,7 +1321,7 @@ SYSCALL_DEFINE2(umount, char __user *, name, int, flags) if (!(flags & UMOUNT_NOFOLLOW)) lookup_flags |= LOOKUP_FOLLOW; - retval = user_path_umountat(AT_FDCWD, name, lookup_flags, &path); + retval = user_path_mountpoint_at(AT_FDCWD, name, lookup_flags, &path); if (retval) goto out; mnt = real_mount(path.mnt); diff --git a/include/linux/namei.h b/include/linux/namei.h index cd09751c71a0..53c18f00d9fb 100644 --- a/include/linux/namei.h +++ b/include/linux/namei.h @@ -58,7 +58,6 @@ enum {LAST_NORM, LAST_ROOT, LAST_DOT, LAST_DOTDOT, LAST_BIND}; extern int user_path_at(int, const char __user *, unsigned, struct path *); extern int user_path_at_empty(int, const char __user *, unsigned, struct path *, int *empty); -extern int user_path_umountat(int, const char __user *, unsigned int, struct path *); #define user_path(name, path) user_path_at(AT_FDCWD, name, LOOKUP_FOLLOW, path) #define user_lpath(name, path) user_path_at(AT_FDCWD, name, 0, path) @@ -71,8 +70,6 @@ extern struct dentry *kern_path_create(int, const char *, struct path *, unsigne extern struct dentry *user_path_create(int, const char __user *, struct path *, unsigned int); extern void done_path_create(struct path *, struct dentry *); extern struct dentry *kern_path_locked(const char *, struct path *); -extern int vfs_path_lookup(struct dentry *, struct vfsmount *, - const char *, unsigned int, struct path *); extern struct dentry *lookup_one_len(const char *, struct dentry *, int); -- cgit v1.2.3 From 2d8646510120bb1eb251ae3381e950805a877763 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Sun, 8 Sep 2013 20:18:44 -0400 Subject: introduce kern_path_mountpoint() Signed-off-by: Al Viro --- fs/namei.c | 35 ++++++++++++++++++++++++----------- include/linux/namei.h | 1 + 2 files changed, 25 insertions(+), 11 deletions(-) (limited to 'fs/namei.c') diff --git a/fs/namei.c b/fs/namei.c index 11184df3307e..e412421210cc 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -2360,6 +2360,20 @@ out: return err; } +static int +filename_mountpoint(int dfd, struct filename *s, struct path *path, + unsigned int flags) +{ + int error = path_mountpoint(dfd, s->name, path, flags | LOOKUP_RCU); + if (unlikely(error == -ECHILD)) + error = path_mountpoint(dfd, s->name, path, flags); + if (unlikely(error == -ESTALE)) + error = path_mountpoint(dfd, s->name, path, flags | LOOKUP_REVAL); + if (likely(!error)) + audit_inode(s, path->dentry, 0); + return error; +} + /** * user_path_mountpoint_at - lookup a path from userland in order to umount it * @dfd: directory file descriptor @@ -2380,23 +2394,22 @@ user_path_mountpoint_at(int dfd, const char __user *name, unsigned int flags, { struct filename *s = getname(name); int error; - if (IS_ERR(s)) return PTR_ERR(s); - - error = path_mountpoint(dfd, s->name, path, flags | LOOKUP_RCU); - if (unlikely(error == -ECHILD)) - error = path_mountpoint(dfd, s->name, path, flags); - if (unlikely(error == -ESTALE)) - error = path_mountpoint(dfd, s->name, path, flags | LOOKUP_REVAL); - - if (likely(!error)) - audit_inode(s, path->dentry, 0); - + error = filename_mountpoint(dfd, s, path, flags); putname(s); return error; } +int +kern_path_mountpoint(int dfd, const char *name, struct path *path, + unsigned int flags) +{ + struct filename s = {.name = name}; + return filename_mountpoint(dfd, &s, path, flags); +} +EXPORT_SYMBOL(kern_path_mountpoint); + /* * It's inline, so penalty for filesystems that don't use sticky bit is * minimal. diff --git a/include/linux/namei.h b/include/linux/namei.h index 53c18f00d9fb..8e47bc7a1665 100644 --- a/include/linux/namei.h +++ b/include/linux/namei.h @@ -70,6 +70,7 @@ extern struct dentry *kern_path_create(int, const char *, struct path *, unsigne extern struct dentry *user_path_create(int, const char __user *, struct path *, unsigned int); extern void done_path_create(struct path *, struct dentry *); extern struct dentry *kern_path_locked(const char *, struct path *); +extern int kern_path_mountpoint(int, const char *, struct path *, unsigned int); extern struct dentry *lookup_one_len(const char *, struct dentry *, int); -- cgit v1.2.3