string: factorize skip_spaces and export it to be generally available

[safe/jmp/linux-2.6] / fs / attr.c

diff --git a/fs/attr.c b/fs/attr.c
index 9fe1b1b..96d394b 100644 (file)
--- a/fs/attr.c
+++ b/fs/attr.c
@@ -18,7 +18,7 @@
 /* Taken over from the old code... */
 
 /* POSIX UID/GID verification for setting inode attributes. */
-int inode_change_ok(struct inode *inode, struct iattr *attr)
+int inode_change_ok(const struct inode *inode, struct iattr *attr)
 {
        int retval = -EPERM;
        unsigned int ia_valid = attr->ia_valid;
@@ -60,9 +60,51 @@ fine:
 error:
        return retval;
 }
-
 EXPORT_SYMBOL(inode_change_ok);
 
+/**
+ * inode_newsize_ok - may this inode be truncated to a given size
+ * @inode:     the inode to be truncated
+ * @offset:    the new size to assign to the inode
+ * @Returns:   0 on success, -ve errno on failure
+ *
+ * inode_newsize_ok will check filesystem limits and ulimits to check that the
+ * new inode size is within limits. inode_newsize_ok will also send SIGXFSZ
+ * when necessary. Caller must not proceed with inode size change if failure is
+ * returned. @inode must be a file (not directory), with appropriate
+ * permissions to allow truncate (inode_newsize_ok does NOT check these
+ * conditions).
+ *
+ * inode_newsize_ok must be called with i_mutex held.
+ */
+int inode_newsize_ok(const struct inode *inode, loff_t offset)
+{
+       if (inode->i_size < offset) {
+               unsigned long limit;
+
+               limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur;
+               if (limit != RLIM_INFINITY && offset > limit)
+                       goto out_sig;
+               if (offset > inode->i_sb->s_maxbytes)
+                       goto out_big;
+       } else {
+               /*
+                * truncation of in-use swapfiles is disallowed - it would
+                * cause subsequent swapout to scribble on the now-freed
+                * blocks.
+                */
+               if (IS_SWAPFILE(inode))
+                       return -ETXTBSY;
+       }
+
+       return 0;
+out_sig:
+       send_sig(SIGXFSZ, current, 0);
+out_big:
+       return -EFBIG;
+}
+EXPORT_SYMBOL(inode_newsize_ok);
+
 int inode_setattr(struct inode * inode, struct iattr * attr)
 {
        unsigned int ia_valid = attr->ia_valid;