Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933194AbbEKSgd (ORCPT ); Mon, 11 May 2015 14:36:33 -0400 Received: from zeniv.linux.org.uk ([195.92.253.2]:47011 "EHLO ZenIV.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754934AbbEKSIR (ORCPT ); Mon, 11 May 2015 14:08:17 -0400 From: Al Viro To: Linus Torvalds Cc: Neil Brown , Christoph Hellwig , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: [PATCH v3 027/110] name: shift nameidata down into user_path_walk() Date: Mon, 11 May 2015 19:06:47 +0100 Message-Id: <1431367690-5223-27-git-send-email-viro@ZenIV.linux.org.uk> X-Mailer: git-send-email 1.7.7.6 In-Reply-To: <20150511180650.GA4147@ZenIV.linux.org.uk> References: <20150511180650.GA4147@ZenIV.linux.org.uk> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 9679 Lines: 334 From: Al Viro that avoids having nameidata on stack during the calls of ->rmdir()/->unlink() and *two* of those during the calls of ->rename(). Signed-off-by: Al Viro --- fs/namei.c | 124 +++++++++++++++++++++++++++++++++---------------------------- 1 file changed, 67 insertions(+), 57 deletions(-) diff --git a/fs/namei.c b/fs/namei.c index 1439aa3..293300c 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -2211,9 +2211,13 @@ EXPORT_SYMBOL(user_path_at); * path-walking is complete. */ static struct filename * -user_path_parent(int dfd, const char __user *path, struct nameidata *nd, +user_path_parent(int dfd, const char __user *path, + struct path *parent, + struct qstr *last, + int *type, unsigned int flags) { + struct nameidata nd; struct filename *s = getname(path); int error; @@ -2223,11 +2227,14 @@ user_path_parent(int dfd, const char __user *path, struct nameidata *nd, if (IS_ERR(s)) return s; - error = filename_lookup(dfd, s, flags | LOOKUP_PARENT, nd); + error = filename_lookup(dfd, s, flags | LOOKUP_PARENT, &nd); if (error) { putname(s); return ERR_PTR(error); } + *parent = nd.path; + *last = nd.last; + *type = nd.last_type; return s; } @@ -3630,14 +3637,17 @@ static long do_rmdir(int dfd, const char __user *pathname) int error = 0; struct filename *name; struct dentry *dentry; - struct nameidata nd; + struct path path; + struct qstr last; + int type; unsigned int lookup_flags = 0; retry: - name = user_path_parent(dfd, pathname, &nd, lookup_flags); + name = user_path_parent(dfd, pathname, + &path, &last, &type, lookup_flags); if (IS_ERR(name)) return PTR_ERR(name); - switch(nd.last_type) { + switch (type) { case LAST_DOTDOT: error = -ENOTEMPTY; goto exit1; @@ -3649,13 +3659,12 @@ retry: goto exit1; } - nd.flags &= ~LOOKUP_PARENT; - error = mnt_want_write(nd.path.mnt); + error = mnt_want_write(path.mnt); if (error) goto exit1; - mutex_lock_nested(&nd.path.dentry->d_inode->i_mutex, I_MUTEX_PARENT); - dentry = __lookup_hash(&nd.last, nd.path.dentry, nd.flags); + mutex_lock_nested(&path.dentry->d_inode->i_mutex, I_MUTEX_PARENT); + dentry = __lookup_hash(&last, path.dentry, lookup_flags); error = PTR_ERR(dentry); if (IS_ERR(dentry)) goto exit2; @@ -3663,17 +3672,17 @@ retry: error = -ENOENT; goto exit3; } - error = security_path_rmdir(&nd.path, dentry); + error = security_path_rmdir(&path, dentry); if (error) goto exit3; - error = vfs_rmdir(nd.path.dentry->d_inode, dentry); + error = vfs_rmdir(path.dentry->d_inode, dentry); exit3: dput(dentry); exit2: - mutex_unlock(&nd.path.dentry->d_inode->i_mutex); - mnt_drop_write(nd.path.mnt); + mutex_unlock(&path.dentry->d_inode->i_mutex); + mnt_drop_write(path.mnt); exit1: - path_put(&nd.path); + path_put(&path); putname(name); if (retry_estale(error, lookup_flags)) { lookup_flags |= LOOKUP_REVAL; @@ -3756,43 +3765,45 @@ static long do_unlinkat(int dfd, const char __user *pathname) int error; struct filename *name; struct dentry *dentry; - struct nameidata nd; + struct path path; + struct qstr last; + int type; struct inode *inode = NULL; struct inode *delegated_inode = NULL; unsigned int lookup_flags = 0; retry: - name = user_path_parent(dfd, pathname, &nd, lookup_flags); + name = user_path_parent(dfd, pathname, + &path, &last, &type, lookup_flags); if (IS_ERR(name)) return PTR_ERR(name); error = -EISDIR; - if (nd.last_type != LAST_NORM) + if (type != LAST_NORM) goto exit1; - nd.flags &= ~LOOKUP_PARENT; - error = mnt_want_write(nd.path.mnt); + error = mnt_want_write(path.mnt); if (error) goto exit1; retry_deleg: - mutex_lock_nested(&nd.path.dentry->d_inode->i_mutex, I_MUTEX_PARENT); - dentry = __lookup_hash(&nd.last, nd.path.dentry, nd.flags); + mutex_lock_nested(&path.dentry->d_inode->i_mutex, I_MUTEX_PARENT); + dentry = __lookup_hash(&last, path.dentry, lookup_flags); error = PTR_ERR(dentry); if (!IS_ERR(dentry)) { /* Why not before? Because we want correct error value */ - if (nd.last.name[nd.last.len]) + if (last.name[last.len]) goto slashes; inode = dentry->d_inode; if (d_is_negative(dentry)) goto slashes; ihold(inode); - error = security_path_unlink(&nd.path, dentry); + error = security_path_unlink(&path, dentry); if (error) goto exit2; - error = vfs_unlink(nd.path.dentry->d_inode, dentry, &delegated_inode); + error = vfs_unlink(path.dentry->d_inode, dentry, &delegated_inode); exit2: dput(dentry); } - mutex_unlock(&nd.path.dentry->d_inode->i_mutex); + mutex_unlock(&path.dentry->d_inode->i_mutex); if (inode) iput(inode); /* truncate the inode here */ inode = NULL; @@ -3801,9 +3812,9 @@ exit2: if (!error) goto retry_deleg; } - mnt_drop_write(nd.path.mnt); + mnt_drop_write(path.mnt); exit1: - path_put(&nd.path); + path_put(&path); putname(name); if (retry_estale(error, lookup_flags)) { lookup_flags |= LOOKUP_REVAL; @@ -4233,14 +4244,15 @@ EXPORT_SYMBOL(vfs_rename); SYSCALL_DEFINE5(renameat2, int, olddfd, const char __user *, oldname, int, newdfd, const char __user *, newname, unsigned int, flags) { - struct dentry *old_dir, *new_dir; struct dentry *old_dentry, *new_dentry; struct dentry *trap; - struct nameidata oldnd, newnd; + struct path old_path, new_path; + struct qstr old_last, new_last; + int old_type, new_type; struct inode *delegated_inode = NULL; struct filename *from; struct filename *to; - unsigned int lookup_flags = 0; + unsigned int lookup_flags = 0, target_flags = LOOKUP_RENAME_TARGET; bool should_retry = false; int error; @@ -4254,47 +4266,45 @@ SYSCALL_DEFINE5(renameat2, int, olddfd, const char __user *, oldname, if ((flags & RENAME_WHITEOUT) && !capable(CAP_MKNOD)) return -EPERM; + if (flags & RENAME_EXCHANGE) + target_flags = 0; + retry: - from = user_path_parent(olddfd, oldname, &oldnd, lookup_flags); + from = user_path_parent(olddfd, oldname, + &old_path, &old_last, &old_type, lookup_flags); if (IS_ERR(from)) { error = PTR_ERR(from); goto exit; } - to = user_path_parent(newdfd, newname, &newnd, lookup_flags); + to = user_path_parent(newdfd, newname, + &new_path, &new_last, &new_type, lookup_flags); if (IS_ERR(to)) { error = PTR_ERR(to); goto exit1; } error = -EXDEV; - if (oldnd.path.mnt != newnd.path.mnt) + if (old_path.mnt != new_path.mnt) goto exit2; - old_dir = oldnd.path.dentry; error = -EBUSY; - if (oldnd.last_type != LAST_NORM) + if (old_type != LAST_NORM) goto exit2; - new_dir = newnd.path.dentry; if (flags & RENAME_NOREPLACE) error = -EEXIST; - if (newnd.last_type != LAST_NORM) + if (new_type != LAST_NORM) goto exit2; - error = mnt_want_write(oldnd.path.mnt); + error = mnt_want_write(old_path.mnt); if (error) goto exit2; - oldnd.flags &= ~LOOKUP_PARENT; - newnd.flags &= ~LOOKUP_PARENT; - if (!(flags & RENAME_EXCHANGE)) - newnd.flags |= LOOKUP_RENAME_TARGET; - retry_deleg: - trap = lock_rename(new_dir, old_dir); + trap = lock_rename(new_path.dentry, old_path.dentry); - old_dentry = __lookup_hash(&oldnd.last, oldnd.path.dentry, oldnd.flags); + old_dentry = __lookup_hash(&old_last, old_path.dentry, lookup_flags); error = PTR_ERR(old_dentry); if (IS_ERR(old_dentry)) goto exit3; @@ -4302,7 +4312,7 @@ retry_deleg: error = -ENOENT; if (d_is_negative(old_dentry)) goto exit4; - new_dentry = __lookup_hash(&newnd.last, newnd.path.dentry, newnd.flags); + new_dentry = __lookup_hash(&new_last, new_path.dentry, lookup_flags | target_flags); error = PTR_ERR(new_dentry); if (IS_ERR(new_dentry)) goto exit4; @@ -4316,16 +4326,16 @@ retry_deleg: if (!d_is_dir(new_dentry)) { error = -ENOTDIR; - if (newnd.last.name[newnd.last.len]) + if (new_last.name[new_last.len]) goto exit5; } } /* unless the source is a directory trailing slashes give -ENOTDIR */ if (!d_is_dir(old_dentry)) { error = -ENOTDIR; - if (oldnd.last.name[oldnd.last.len]) + if (old_last.name[old_last.len]) goto exit5; - if (!(flags & RENAME_EXCHANGE) && newnd.last.name[newnd.last.len]) + if (!(flags & RENAME_EXCHANGE) && new_last.name[new_last.len]) goto exit5; } /* source should not be ancestor of target */ @@ -4338,32 +4348,32 @@ retry_deleg: if (new_dentry == trap) goto exit5; - error = security_path_rename(&oldnd.path, old_dentry, - &newnd.path, new_dentry, flags); + error = security_path_rename(&old_path, old_dentry, + &new_path, new_dentry, flags); if (error) goto exit5; - error = vfs_rename(old_dir->d_inode, old_dentry, - new_dir->d_inode, new_dentry, + error = vfs_rename(old_path.dentry->d_inode, old_dentry, + new_path.dentry->d_inode, new_dentry, &delegated_inode, flags); exit5: dput(new_dentry); exit4: dput(old_dentry); exit3: - unlock_rename(new_dir, old_dir); + unlock_rename(new_path.dentry, old_path.dentry); if (delegated_inode) { error = break_deleg_wait(&delegated_inode); if (!error) goto retry_deleg; } - mnt_drop_write(oldnd.path.mnt); + mnt_drop_write(old_path.mnt); exit2: if (retry_estale(error, lookup_flags)) should_retry = true; - path_put(&newnd.path); + path_put(&new_path); putname(to); exit1: - path_put(&oldnd.path); + path_put(&old_path); putname(from); if (should_retry) { should_retry = false; -- 2.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/