Merge tag 'gfs2-for-5.4' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2

[linux.git] / fs / inode.c

diff --git a/fs/inode.c b/fs/inode.c
index 2bf21e2c90fc8adb53f4c360ed0dbf30230806c9..64bf28cf05cde859ab0b72abd4a30cbdc7e3912b 100644 (file)
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -1899,6 +1899,26 @@ int file_update_time(struct file *file)
 }
 EXPORT_SYMBOL(file_update_time);
 
+/* Caller must hold the file's inode lock */
+int file_modified(struct file *file)
+{
+       int err;
+
+       /*
+        * Clear the security bits if the process is not being run by root.
+        * This keeps people from modifying setuid and setgid binaries.
+        */
+       err = file_remove_privs(file);
+       if (err)
+               return err;
+
+       if (unlikely(file->f_mode & FMODE_NOCMTIME))
+               return 0;
+
+       return file_update_time(file);
+}
+EXPORT_SYMBOL(file_modified);
+
 int inode_needs_sync(struct inode *inode)
 {
        if (IS_SYNC(inode))
@@ -2146,6 +2166,37 @@ struct timespec64 timespec64_trunc(struct timespec64 t, unsigned gran)
 }
 EXPORT_SYMBOL(timespec64_trunc);
 
+/**
+ * timestamp_truncate - Truncate timespec to a granularity
+ * @t: Timespec
+ * @inode: inode being updated
+ *
+ * Truncate a timespec to the granularity supported by the fs
+ * containing the inode. Always rounds down. gran must
+ * not be 0 nor greater than a second (NSEC_PER_SEC, or 10^9 ns).
+ */
+struct timespec64 timestamp_truncate(struct timespec64 t, struct inode *inode)
+{
+       struct super_block *sb = inode->i_sb;
+       unsigned int gran = sb->s_time_gran;
+
+       t.tv_sec = clamp(t.tv_sec, sb->s_time_min, sb->s_time_max);
+       if (unlikely(t.tv_sec == sb->s_time_max || t.tv_sec == sb->s_time_min))
+               t.tv_nsec = 0;
+
+       /* Avoid division in the common cases 1 ns and 1 s. */
+       if (gran == 1)
+               ; /* nothing */
+       else if (gran == NSEC_PER_SEC)
+               t.tv_nsec = 0;
+       else if (gran > 1 && gran < NSEC_PER_SEC)
+               t.tv_nsec -= t.tv_nsec % gran;
+       else
+               WARN(1, "invalid file time granularity: %u", gran);
+       return t;
+}
+EXPORT_SYMBOL(timestamp_truncate);
+
 /**
  * current_time - Return FS time
  * @inode: inode.
@@ -2167,6 +2218,92 @@ struct timespec64 current_time(struct inode *inode)
                return now;
        }
 
-       return timespec64_trunc(now, inode->i_sb->s_time_gran);
+       return timestamp_truncate(now, inode);
 }
 EXPORT_SYMBOL(current_time);
+
+/*
+ * Generic function to check FS_IOC_SETFLAGS values and reject any invalid
+ * configurations.
+ *
+ * Note: the caller should be holding i_mutex, or else be sure that they have
+ * exclusive access to the inode structure.
+ */
+int vfs_ioc_setflags_prepare(struct inode *inode, unsigned int oldflags,
+                            unsigned int flags)
+{
+       /*
+        * The IMMUTABLE and APPEND_ONLY flags can only be changed by
+        * the relevant capability.
+        *
+        * This test looks nicer. Thanks to Pauline Middelink
+        */
+       if ((flags ^ oldflags) & (FS_APPEND_FL | FS_IMMUTABLE_FL) &&
+           !capable(CAP_LINUX_IMMUTABLE))
+               return -EPERM;
+
+       return 0;
+}
+EXPORT_SYMBOL(vfs_ioc_setflags_prepare);
+
+/*
+ * Generic function to check FS_IOC_FSSETXATTR values and reject any invalid
+ * configurations.
+ *
+ * Note: the caller should be holding i_mutex, or else be sure that they have
+ * exclusive access to the inode structure.
+ */
+int vfs_ioc_fssetxattr_check(struct inode *inode, const struct fsxattr *old_fa,
+                            struct fsxattr *fa)
+{
+       /*
+        * Can't modify an immutable/append-only file unless we have
+        * appropriate permission.
+        */
+       if ((old_fa->fsx_xflags ^ fa->fsx_xflags) &
+                       (FS_XFLAG_IMMUTABLE | FS_XFLAG_APPEND) &&
+           !capable(CAP_LINUX_IMMUTABLE))
+               return -EPERM;
+
+       /*
+        * Project Quota ID state is only allowed to change from within the init
+        * namespace. Enforce that restriction only if we are trying to change
+        * the quota ID state. Everything else is allowed in user namespaces.
+        */
+       if (current_user_ns() != &init_user_ns) {
+               if (old_fa->fsx_projid != fa->fsx_projid)
+                       return -EINVAL;
+               if ((old_fa->fsx_xflags ^ fa->fsx_xflags) &
+                               FS_XFLAG_PROJINHERIT)
+                       return -EINVAL;
+       }
+
+       /* Check extent size hints. */
+       if ((fa->fsx_xflags & FS_XFLAG_EXTSIZE) && !S_ISREG(inode->i_mode))
+               return -EINVAL;
+
+       if ((fa->fsx_xflags & FS_XFLAG_EXTSZINHERIT) &&
+                       !S_ISDIR(inode->i_mode))
+               return -EINVAL;
+
+       if ((fa->fsx_xflags & FS_XFLAG_COWEXTSIZE) &&
+           !S_ISREG(inode->i_mode) && !S_ISDIR(inode->i_mode))
+               return -EINVAL;
+
+       /*
+        * It is only valid to set the DAX flag on regular files and
+        * directories on filesystems.
+        */
+       if ((fa->fsx_xflags & FS_XFLAG_DAX) &&
+           !(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode)))
+               return -EINVAL;
+
+       /* Extent size hints of zero turn off the flags. */
+       if (fa->fsx_extsize == 0)
+               fa->fsx_xflags &= ~(FS_XFLAG_EXTSIZE | FS_XFLAG_EXTSZINHERIT);
+       if (fa->fsx_cowextsize == 0)
+               fa->fsx_xflags &= ~FS_XFLAG_COWEXTSIZE;
+
+       return 0;
+}
+EXPORT_SYMBOL(vfs_ioc_fssetxattr_check);