mm/filemap.c: make global sync not clear error status of individual inodes

[linux-beck.git] / mm / filemap.c

diff --git a/mm/filemap.c b/mm/filemap.c
index 1fe962b49f31e47fd6451c99ebe4e9c94fd8b2e8..884766da11655afb1bf54d176ed32da732aa3f3d 100644 (file)
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -331,23 +331,14 @@ int filemap_flush(struct address_space *mapping)
 }
 EXPORT_SYMBOL(filemap_flush);
 
-/**
- * filemap_fdatawait_range - wait for writeback to complete
- * @mapping:           address space structure to wait for
- * @start_byte:                offset in bytes where the range starts
- * @end_byte:          offset in bytes where the range ends (inclusive)
- *
- * Walk the list of under-writeback pages of the given address space
- * in the given range and wait for all of them.
- */
-int filemap_fdatawait_range(struct address_space *mapping, loff_t start_byte,
-                           loff_t end_byte)
+static int __filemap_fdatawait_range(struct address_space *mapping,
+                                    loff_t start_byte, loff_t end_byte)
 {
        pgoff_t index = start_byte >> PAGE_CACHE_SHIFT;
        pgoff_t end = end_byte >> PAGE_CACHE_SHIFT;
        struct pagevec pvec;
        int nr_pages;
-       int ret2, ret = 0;
+       int ret = 0;
 
        if (end_byte < start_byte)
                goto out;
@@ -374,6 +365,29 @@ int filemap_fdatawait_range(struct address_space *mapping, loff_t start_byte,
                cond_resched();
        }
 out:
+       return ret;
+}
+
+/**
+ * filemap_fdatawait_range - wait for writeback to complete
+ * @mapping:           address space structure to wait for
+ * @start_byte:                offset in bytes where the range starts
+ * @end_byte:          offset in bytes where the range ends (inclusive)
+ *
+ * Walk the list of under-writeback pages of the given address space
+ * in the given range and wait for all of them.  Check error status of
+ * the address space and return it.
+ *
+ * Since the error status of the address space is cleared by this function,
+ * callers are responsible for checking the return value and handling and/or
+ * reporting the error.
+ */
+int filemap_fdatawait_range(struct address_space *mapping, loff_t start_byte,
+                           loff_t end_byte)
+{
+       int ret, ret2;
+
+       ret = __filemap_fdatawait_range(mapping, start_byte, end_byte);
        ret2 = filemap_check_errors(mapping);
        if (!ret)
                ret = ret2;
@@ -382,12 +396,39 @@ out:
 }
 EXPORT_SYMBOL(filemap_fdatawait_range);
 
+/**
+ * filemap_fdatawait_keep_errors - wait for writeback without clearing errors
+ * @mapping: address space structure to wait for
+ *
+ * Walk the list of under-writeback pages of the given address space
+ * and wait for all of them.  Unlike filemap_fdatawait(), this function
+ * does not clear error status of the address space.
+ *
+ * Use this function if callers don't handle errors themselves.  Expected
+ * call sites are system-wide / filesystem-wide data flushers: e.g. sync(2),
+ * fsfreeze(8)
+ */
+void filemap_fdatawait_keep_errors(struct address_space *mapping)
+{
+       loff_t i_size = i_size_read(mapping->host);
+
+       if (i_size == 0)
+               return;
+
+       __filemap_fdatawait_range(mapping, 0, i_size - 1);
+}
+
 /**
  * filemap_fdatawait - wait for all under-writeback pages to complete
  * @mapping: address space structure to wait for
  *
  * Walk the list of under-writeback pages of the given address space
- * and wait for all of them.
+ * and wait for all of them.  Check error status of the address space
+ * and return it.
+ *
+ * Since the error status of the address space is cleared by this function,
+ * callers are responsible for checking the return value and handling and/or
+ * reporting the error.
  */
 int filemap_fdatawait(struct address_space *mapping)
 {