uml: make hostfs_setattr() support operations on unlinked open files

This patch allows hostfs_setattr() to work on unlinked open files by calling
set_attr() (the userspace part) with the inode's fd.

Without this, applications that depend on doing attribute changes to unlinked
open files will fail.

It works by using the fd versions instead of the path ones (for example
fchmod() instead of chmod(), fchown() instead of chown()) when an fd is
available.

Signed-off-by: Alberto Bertogli <albertito@gmail.com>
Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/hostfs/hostfs.h b/fs/hostfs/hostfs.h
index 70543b17e4c733315d73089537e3a85b8b7cf96a..d8850c701564ecf65a9ab176f87654de09cf66d0 100644 (file)
--- a/fs/hostfs/hostfs.h
+++ b/fs/hostfs/hostfs.h
@@ -55,7 +55,7 @@ extern int stat_file(const char *path, unsigned long long *inode_out,
                     int *mode_out, int *nlink_out, int *uid_out, int *gid_out,
                     unsigned long long *size_out, struct timespec *atime_out,
                     struct timespec *mtime_out, struct timespec *ctime_out,
-                    int *blksize_out, unsigned long long *blocks_out);
+                    int *blksize_out, unsigned long long *blocks_out, int fd);
 extern int access_file(char *path, int r, int w, int x);
 extern int open_file(char *path, int r, int w, int append);
 extern int file_type(const char *path, int *maj, int *min);
@@ -71,7 +71,7 @@ extern int lseek_file(int fd, long long offset, int whence);
 extern int fsync_file(int fd, int datasync);
 extern int file_create(char *name, int ur, int uw, int ux, int gr,
                       int gw, int gx, int or, int ow, int ox);
-extern int set_attr(const char *file, struct hostfs_iattr *attrs);
+extern int set_attr(const char *file, struct hostfs_iattr *attrs, int fd);
 extern int make_symlink(const char *from, const char *to);
 extern int unlink_file(const char *file);
 extern int do_mkdir(const char *file, int mode);

diff --git a/fs/hostfs/hostfs_kern.c b/fs/hostfs/hostfs_kern.c
index fd301a91012243e25fe2ab9a77db3a9bda9b6acd..4e8bb2fba0489767e940303698b4f0891d3575f9 100644 (file)
--- a/fs/hostfs/hostfs_kern.c
+++ b/fs/hostfs/hostfs_kern.c
@@ -147,7 +147,7 @@ static int read_name(struct inode *ino, char *name)
 
        err = stat_file(name, &i_ino, &i_mode, &i_nlink, &ino->i_uid,
                        &ino->i_gid, &i_size, &ino->i_atime, &ino->i_mtime,
-                       &ino->i_ctime, &i_blksize, &i_blocks);
+                       &ino->i_ctime, &i_blksize, &i_blocks, -1);
        if(err)
                return(err);
 
@@ -820,6 +820,8 @@ int hostfs_setattr(struct dentry *dentry, struct iattr *attr)
        char *name;
        int err;
 
+       int fd = HOSTFS_I(dentry->d_inode)->fd;
+
        err = inode_change_ok(dentry->d_inode, attr);
        if (err)
                return err;
@@ -864,7 +866,7 @@ int hostfs_setattr(struct dentry *dentry, struct iattr *attr)
        }
        name = dentry_name(dentry, 0);
        if(name == NULL) return(-ENOMEM);
-       err = set_attr(name, &attrs);
+       err = set_attr(name, &attrs, fd);
        kfree(name);
        if(err)
                return(err);

diff --git a/fs/hostfs/hostfs_user.c b/fs/hostfs/hostfs_user.c
index 1ed5ea389f15bcda52f32171bb725fa9f0ce7c39..0acf562a5f06f3932a6234db0ac38c4c0386749d 100644 (file)
--- a/fs/hostfs/hostfs_user.c
+++ b/fs/hostfs/hostfs_user.c
@@ -21,12 +21,16 @@ int stat_file(const char *path, unsigned long long *inode_out, int *mode_out,
              int *nlink_out, int *uid_out, int *gid_out,
              unsigned long long *size_out, struct timespec *atime_out,
              struct timespec *mtime_out, struct timespec *ctime_out,
-             int *blksize_out, unsigned long long *blocks_out)
+             int *blksize_out, unsigned long long *blocks_out, int fd)
 {
        struct stat64 buf;
 
-       if(lstat64(path, &buf) < 0)
+       if(fd >= 0) {
+               if (fstat64(fd, &buf) < 0)
+                       return(-errno);
+       } else if(lstat64(path, &buf) < 0) {
                return(-errno);
+       }
 
        if(inode_out != NULL) *inode_out = buf.st_ino;
        if(mode_out != NULL) *mode_out = buf.st_mode;
@@ -202,58 +206,82 @@ int file_create(char *name, int ur, int uw, int ux, int gr,
        return(fd);
 }
 
-int set_attr(const char *file, struct hostfs_iattr *attrs)
+int set_attr(const char *file, struct hostfs_iattr *attrs, int fd)
 {
-       struct utimbuf buf;
+       struct timeval times[2];
+       struct timespec atime_ts, mtime_ts;
        int err, ma;
 
-       if(attrs->ia_valid & HOSTFS_ATTR_MODE){
-               if(chmod(file, attrs->ia_mode) != 0) return(-errno);
-       }
-       if(attrs->ia_valid & HOSTFS_ATTR_UID){
-               if(chown(file, attrs->ia_uid, -1)) return(-errno);
+       if (attrs->ia_valid & HOSTFS_ATTR_MODE) {
+               if (fd >= 0) {
+                       if (fchmod(fd, attrs->ia_mode) != 0)
+                               return (-errno);
+               } else if (chmod(file, attrs->ia_mode) != 0) {
+                       return (-errno);
+               }
        }
-       if(attrs->ia_valid & HOSTFS_ATTR_GID){
-               if(chown(file, -1, attrs->ia_gid)) return(-errno);
+       if (attrs->ia_valid & HOSTFS_ATTR_UID) {
+               if (fd >= 0) {
+                       if (fchown(fd, attrs->ia_uid, -1))
+                               return (-errno);
+               } else if(chown(file, attrs->ia_uid, -1)) {
+                       return (-errno);
+               }
        }
-       if(attrs->ia_valid & HOSTFS_ATTR_SIZE){
-               if(truncate(file, attrs->ia_size)) return(-errno);
+       if (attrs->ia_valid & HOSTFS_ATTR_GID) {
+               if (fd >= 0) {
+                       if (fchown(fd, -1, attrs->ia_gid))
+                               return (-errno);
+               } else if (chown(file, -1, attrs->ia_gid)) {
+                       return (-errno);
+               }
        }
-       ma = HOSTFS_ATTR_ATIME_SET | HOSTFS_ATTR_MTIME_SET;
-       if((attrs->ia_valid & ma) == ma){
-               buf.actime = attrs->ia_atime.tv_sec;
-               buf.modtime = attrs->ia_mtime.tv_sec;
-               if(utime(file, &buf) != 0) return(-errno);
+       if (attrs->ia_valid & HOSTFS_ATTR_SIZE) {
+               if (fd >= 0) {
+                       if (ftruncate(fd, attrs->ia_size))
+                               return (-errno);
+               } else if (truncate(file, attrs->ia_size)) {
+                       return (-errno);
+               }
        }
-       else {
-               struct timespec ts;
-
-               if(attrs->ia_valid & HOSTFS_ATTR_ATIME_SET){
-                       err = stat_file(file, NULL, NULL, NULL, NULL, NULL,
-                                       NULL, NULL, &ts, NULL, NULL, NULL);
-                       if(err != 0)
-                               return(err);
-                       buf.actime = attrs->ia_atime.tv_sec;
-                       buf.modtime = ts.tv_sec;
-                       if(utime(file, &buf) != 0)
-                               return(-errno);
+
+       /* Update accessed and/or modified time, in two parts: first set
+        * times according to the changes to perform, and then call futimes()
+        * or utimes() to apply them. */
+       ma = (HOSTFS_ATTR_ATIME_SET | HOSTFS_ATTR_MTIME_SET);
+       if (attrs->ia_valid & ma) {
+               err = stat_file(file, NULL, NULL, NULL, NULL, NULL, NULL,
+                               &atime_ts, &mtime_ts, NULL, NULL, NULL, fd);
+               if (err != 0)
+                       return err;
+
+               times[0].tv_sec = atime_ts.tv_sec;
+               times[0].tv_usec = atime_ts.tv_nsec * 1000;
+               times[1].tv_sec = mtime_ts.tv_sec;
+               times[1].tv_usec = mtime_ts.tv_nsec * 1000;
+
+               if (attrs->ia_valid & HOSTFS_ATTR_ATIME_SET) {
+                       times[0].tv_sec = attrs->ia_atime.tv_sec;
+                       times[0].tv_usec = attrs->ia_atime.tv_nsec * 1000;
                }
-               if(attrs->ia_valid & HOSTFS_ATTR_MTIME_SET){
-                       err = stat_file(file, NULL, NULL, NULL, NULL, NULL,
-                                       NULL, &ts, NULL, NULL, NULL, NULL);
-                       if(err != 0)
-                               return(err);
-                       buf.actime = ts.tv_sec;
-                       buf.modtime = attrs->ia_mtime.tv_sec;
-                       if(utime(file, &buf) != 0)
-                               return(-errno);
+               if (attrs->ia_valid & HOSTFS_ATTR_MTIME_SET) {
+                       times[1].tv_sec = attrs->ia_mtime.tv_sec;
+                       times[1].tv_usec = attrs->ia_mtime.tv_nsec * 1000;
+               }
+
+               if (fd >= 0) {
+                       if (futimes(fd, times) != 0)
+                               return (-errno);
+               } else if (utimes(file, times) != 0) {
+                       return (-errno);
                }
        }
+
        if(attrs->ia_valid & HOSTFS_ATTR_CTIME) ;
        if(attrs->ia_valid & (HOSTFS_ATTR_ATIME | HOSTFS_ATTR_MTIME)){
                err = stat_file(file, NULL, NULL, NULL, NULL, NULL, NULL,
                                &attrs->ia_atime, &attrs->ia_mtime, NULL,
-                               NULL, NULL);
+                               NULL, NULL, fd);
                if(err != 0) return(err);
        }
        return(0);