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Subject[patch 13/15] vfs: utimes cleanup
From: Miklos Szeredi <mszeredi@suse.cz>

Untange the mess that is do_utimes()

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
CC: Ulrich Drepper <drepper@redhat.com>
---
fs/utimes.c | 163 +++++++++++++++++++++++++++++++++---------------------------
1 file changed, 91 insertions(+), 72 deletions(-)

Index: linux-2.6/fs/utimes.c
===================================================================
--- linux-2.6.orig/fs/utimes.c 2008-05-05 11:29:26.000000000 +0200
+++ linux-2.6/fs/utimes.c 2008-05-05 11:29:28.000000000 +0200
@@ -53,54 +53,10 @@ static bool nsec_valid(long nsec)
return nsec >= 0 && nsec <= 999999999;
}

-/* If times==NULL, set access and modification to current time,
- * must be owner or have write permission.
- * Else, update from *times, must be owner or super user.
- */
-long do_utimes(int dfd, char __user *filename, struct timespec *times, int flags)
+static int utimes_common(struct path *path, struct timespec *times)
{
int error;
- struct nameidata nd;
- struct dentry *dentry;
- struct inode *inode;
struct iattr newattrs;
- struct file *f = NULL;
- struct vfsmount *mnt;
-
- error = -EINVAL;
- if (times && (!nsec_valid(times[0].tv_nsec) ||
- !nsec_valid(times[1].tv_nsec))) {
- goto out;
- }
-
- if (flags & ~AT_SYMLINK_NOFOLLOW)
- goto out;
-
- if (filename == NULL && dfd != AT_FDCWD) {
- error = -EINVAL;
- if (flags & AT_SYMLINK_NOFOLLOW)
- goto out;
-
- error = -EBADF;
- f = fget(dfd);
- if (!f)
- goto out;
- dentry = f->f_path.dentry;
- mnt = f->f_path.mnt;
- } else {
- error = __user_walk_fd(dfd, filename, (flags & AT_SYMLINK_NOFOLLOW) ? 0 : LOOKUP_FOLLOW, &nd);
- if (error)
- goto out;
-
- dentry = nd.path.dentry;
- mnt = nd.path.mnt;
- }
-
- inode = dentry->d_inode;
-
- error = mnt_want_write(mnt);
- if (error)
- goto dput_and_out;

/* Don't worry, the checks are done in inode_change_ok() */
newattrs.ia_valid = ATTR_CTIME | ATTR_MTIME | ATTR_ATIME;
@@ -121,40 +77,103 @@ long do_utimes(int dfd, char __user *fil
newattrs.ia_valid |= ATTR_MTIME_SET;
}
}
+ mutex_lock(&path->dentry->d_inode->i_mutex);
+ error = mnt_want_write(path->mnt);
+ if (!error) {
+ error = notify_change(path->dentry, &newattrs);
+ mnt_drop_write(path->mnt);
+ }
+ mutex_unlock(&path->dentry->d_inode->i_mutex);
+
+ return error;
+}
+
+/*
+ * If times is NULL or both times are either UTIME_OMIT or UTIME_NOW, then
+ * need to check permissions, because inode_change_ok() won't do it.
+ */
+static bool utimes_need_permission(struct timespec *times)
+{
+ return !times || (nsec_special(times[0].tv_nsec) &&
+ nsec_special(times[1].tv_nsec));
+}
+
+static int do_fd_utimes(int fd, struct timespec *times)
+{
+ int error;
+ struct file *file = fget(fd);
+
+ if (!file)
+ return -EBADF;
+
+ if (utimes_need_permission(times)) {
+ struct inode *inode = file->f_path.dentry->d_inode;
+
+ error = -EACCES;
+ if (IS_IMMUTABLE(inode))
+ goto out_fput;
+
+ if (!is_owner_or_cap(inode) && !(file->f_mode & FMODE_WRITE))
+ goto out_fput;
+ }
+ error = utimes_common(&file->f_path, times);
+
+ out_fput:
+ fput(file);
+
+ return error;
+}
+
+/* If times==NULL, set access and modification to current time,
+ * must be owner or have write permission.
+ * Else, update from *times, must be owner or super user.
+ */
+long do_utimes(int dfd, char __user *filename, struct timespec *times,
+ int flags)
+{
+ int error;
+ struct nameidata nd;
+ int lookup_flags;
+
+ if (times && (!nsec_valid(times[0].tv_nsec) ||
+ !nsec_valid(times[1].tv_nsec))) {
+ return -EINVAL;
+ }
+
+ if (filename == NULL && dfd != AT_FDCWD) {
+ if (flags)
+ return -EINVAL;
+
+ return do_fd_utimes(dfd, times);
+ }
+
+ if (flags & ~AT_SYMLINK_NOFOLLOW)
+ return -EINVAL;
+
+ lookup_flags = (flags & AT_SYMLINK_NOFOLLOW) ? 0 : LOOKUP_FOLLOW;
+ error = __user_walk_fd(dfd, filename, lookup_flags, &nd);
+ if (error)
+ return error;
+
+
+ if (utimes_need_permission(times)) {
+ struct inode *inode = nd.path.dentry->d_inode;

- /*
- * If times is NULL or both times are either UTIME_OMIT or
- * UTIME_NOW, then need to check permissions, because
- * inode_change_ok() won't do it.
- */
- if (!times || (nsec_special(times[0].tv_nsec) &&
- nsec_special(times[1].tv_nsec))) {
error = -EACCES;
if (IS_IMMUTABLE(inode))
- goto mnt_drop_write_and_out;
+ goto out_path_put;

if (!is_owner_or_cap(inode)) {
- if (f) {
- if (!(f->f_mode & FMODE_WRITE))
- goto mnt_drop_write_and_out;
- } else {
- error = vfs_permission(&nd, MAY_WRITE);
- if (error)
- goto mnt_drop_write_and_out;
- }
+ error = vfs_permission(&nd, MAY_WRITE);
+ if (error)
+ goto out_path_put;
}
}
- mutex_lock(&inode->i_mutex);
- error = notify_change(dentry, &newattrs);
- mutex_unlock(&inode->i_mutex);
-mnt_drop_write_and_out:
- mnt_drop_write(mnt);
-dput_and_out:
- if (f)
- fput(f);
- else
- path_put(&nd.path);
-out:
+ error = utimes_common(&nd.path, times);
+
+ out_path_put:
+ path_put(&nd.path);
+
return error;
}

--


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