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    Subject[patch 08/22] vfs: immutable inode checking cleanup
    From: Miklos Szeredi <mszeredi@suse.cz>

    Move the immutable and append-only checks from chmod, chown and utimes
    into notify_change(). Checks for immutable and append-only files are
    always performed by the VFS and not by the filesystem (see
    permission() and may_...() in namei.c), so these belong in
    notify_change(), and not in inode_change_ok().

    This causes the following semantic changes in sys_utimensat(), if both
    times are either UTIME_NOW or UTIME_OMIT:

    - if inode is immutable, then -EACCESS is returned instead of -EPERM
    - if inode is append-only, then success is returned instead of -EPERM

    This should be OK, becuase this makes the UTIME_NOW on both behave
    exactly the same as times == NULL. If one of the times is UTIME_OMIT,
    and the other is UTIME_NOW, it also makes no sense to return a
    different error for immutable or append-only files.

    Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
    CC: Ulrich Drepper <drepper@redhat.com>
    ---
    fs/attr.c | 6 ++++++
    fs/open.c | 24 ++----------------------
    fs/utimes.c | 4 ----
    3 files changed, 8 insertions(+), 26 deletions(-)

    Index: linux-2.6/fs/open.c
    ===================================================================
    --- linux-2.6.orig/fs/open.c 2008-05-16 17:50:35.000000000 +0200
    +++ linux-2.6/fs/open.c 2008-05-16 17:50:45.000000000 +0200
    @@ -582,9 +582,6 @@ asmlinkage long sys_fchmod(unsigned int
    err = mnt_want_write(file->f_path.mnt);
    if (err)
    goto out_putf;
    - err = -EPERM;
    - if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
    - goto out_drop_write;
    mutex_lock(&inode->i_mutex);
    if (mode == (mode_t) -1)
    mode = inode->i_mode;
    @@ -592,8 +589,6 @@ asmlinkage long sys_fchmod(unsigned int
    newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
    err = notify_change(dentry, &newattrs);
    mutex_unlock(&inode->i_mutex);
    -
    -out_drop_write:
    mnt_drop_write(file->f_path.mnt);
    out_putf:
    fput(file);
    @@ -617,11 +612,6 @@ asmlinkage long sys_fchmodat(int dfd, co
    error = mnt_want_write(nd.path.mnt);
    if (error)
    goto dput_and_out;
    -
    - error = -EPERM;
    - if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
    - goto out_drop_write;
    -
    mutex_lock(&inode->i_mutex);
    if (mode == (mode_t) -1)
    mode = inode->i_mode;
    @@ -629,8 +619,6 @@ asmlinkage long sys_fchmodat(int dfd, co
    newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
    error = notify_change(nd.path.dentry, &newattrs);
    mutex_unlock(&inode->i_mutex);
    -
    -out_drop_write:
    mnt_drop_write(nd.path.mnt);
    dput_and_out:
    path_put(&nd.path);
    @@ -645,18 +633,10 @@ asmlinkage long sys_chmod(const char __u

    static int chown_common(struct dentry * dentry, uid_t user, gid_t group)
    {
    - struct inode * inode;
    + struct inode *inode = dentry->d_inode;
    int error;
    struct iattr newattrs;

    - error = -ENOENT;
    - if (!(inode = dentry->d_inode)) {
    - printk(KERN_ERR "chown_common: NULL inode\n");
    - goto out;
    - }
    - error = -EPERM;
    - if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
    - goto out;
    newattrs.ia_valid = ATTR_CTIME;
    if (user != (uid_t) -1) {
    newattrs.ia_valid |= ATTR_UID;
    @@ -672,7 +652,7 @@ static int chown_common(struct dentry *
    mutex_lock(&inode->i_mutex);
    error = notify_change(dentry, &newattrs);
    mutex_unlock(&inode->i_mutex);
    -out:
    +
    return error;
    }

    Index: linux-2.6/fs/attr.c
    ===================================================================
    --- linux-2.6.orig/fs/attr.c 2008-05-16 17:50:35.000000000 +0200
    +++ linux-2.6/fs/attr.c 2008-05-16 17:50:45.000000000 +0200
    @@ -108,6 +108,12 @@ int notify_change(struct dentry * dentry
    struct timespec now;
    unsigned int ia_valid = attr->ia_valid;

    + if (ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID |
    + ATTR_ATIME_SET | ATTR_MTIME_SET)) {
    + if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
    + return -EPERM;
    + }
    +
    now = current_fs_time(inode->i_sb);

    attr->ia_ctime = now;
    Index: linux-2.6/fs/utimes.c
    ===================================================================
    --- linux-2.6.orig/fs/utimes.c 2008-05-16 17:50:35.000000000 +0200
    +++ linux-2.6/fs/utimes.c 2008-05-16 17:50:45.000000000 +0200
    @@ -105,10 +105,6 @@ long do_utimes(int dfd, char __user *fil
    /* Don't worry, the checks are done in inode_change_ok() */
    newattrs.ia_valid = ATTR_CTIME | ATTR_MTIME | ATTR_ATIME;
    if (times) {
    - error = -EPERM;
    - if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
    - goto mnt_drop_write_and_out;
    -
    if (times[0].tv_nsec == UTIME_OMIT)
    newattrs.ia_valid &= ~ATTR_ATIME;
    else if (times[0].tv_nsec != UTIME_NOW) {
    --


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