}
/*
- * block_write_begin takes care of the basic task of block allocation and
- * bringing partial write blocks uptodate first.
- *
- * If *pagep is not NULL, then block_write_begin uses the locked page
- * at *pagep rather than allocating its own. In this case, the page will
- * not be unlocked or deallocated on failure.
+ * Filesystems implementing the new truncate sequence should use the
+ * _newtrunc postfix variant which won't incorrectly call vmtruncate.
+ * The filesystem needs to handle block truncation upon failure.
*/
-int block_write_begin(struct file *file, struct address_space *mapping,
+int block_write_begin_newtrunc(struct file *file, struct address_space *mapping,
loff_t pos, unsigned len, unsigned flags,
struct page **pagep, void **fsdata,
get_block_t *get_block)
unlock_page(page);
page_cache_release(page);
*pagep = NULL;
-
- /*
- * prepare_write() may have instantiated a few blocks
- * outside i_size. Trim these off again. Don't need
- * i_size_read because we hold i_mutex.
- */
- if (pos + len > inode->i_size)
- vmtruncate(inode, inode->i_size);
}
}
out:
return status;
}
+EXPORT_SYMBOL(block_write_begin_newtrunc);
+
+/*
+ * block_write_begin takes care of the basic task of block allocation and
+ * bringing partial write blocks uptodate first.
+ *
+ * If *pagep is not NULL, then block_write_begin uses the locked page
+ * at *pagep rather than allocating its own. In this case, the page will
+ * not be unlocked or deallocated on failure.
+ */
+int block_write_begin(struct file *file, struct address_space *mapping,
+ loff_t pos, unsigned len, unsigned flags,
+ struct page **pagep, void **fsdata,
+ get_block_t *get_block)
+{
+ int ret;
+
+ ret = block_write_begin_newtrunc(file, mapping, pos, len, flags,
+ pagep, fsdata, get_block);
+
+ /*
+ * prepare_write() may have instantiated a few blocks
+ * outside i_size. Trim these off again. Don't need
+ * i_size_read because we hold i_mutex.
+ *
+ * Filesystems which pass down their own page also cannot
+ * call into vmtruncate here because it would lead to lock
+ * inversion problems (*pagep is locked). This is a further
+ * example of where the old truncate sequence is inadequate.
+ */
+ if (unlikely(ret) && *pagep == NULL) {
+ loff_t isize = mapping->host->i_size;
+ if (pos + len > isize)
+ vmtruncate(mapping->host, isize);
+ }
+
+ return ret;
+}
EXPORT_SYMBOL(block_write_begin);
int block_write_end(struct file *file, struct address_space *mapping,
* For moronic filesystems that do not allow holes in file.
* We may have to extend the file.
*/
-int cont_write_begin(struct file *file, struct address_space *mapping,
+int cont_write_begin_newtrunc(struct file *file, struct address_space *mapping,
loff_t pos, unsigned len, unsigned flags,
struct page **pagep, void **fsdata,
get_block_t *get_block, loff_t *bytes)
}
*pagep = NULL;
- err = block_write_begin(file, mapping, pos, len,
+ err = block_write_begin_newtrunc(file, mapping, pos, len,
flags, pagep, fsdata, get_block);
out:
return err;
}
+EXPORT_SYMBOL(cont_write_begin_newtrunc);
+
+int cont_write_begin(struct file *file, struct address_space *mapping,
+ loff_t pos, unsigned len, unsigned flags,
+ struct page **pagep, void **fsdata,
+ get_block_t *get_block, loff_t *bytes)
+{
+ int ret;
+
+ ret = cont_write_begin_newtrunc(file, mapping, pos, len, flags,
+ pagep, fsdata, get_block, bytes);
+ if (unlikely(ret)) {
+ loff_t isize = mapping->host->i_size;
+ if (pos + len > isize)
+ vmtruncate(mapping->host, isize);
+ }
+
+ return ret;
+}
EXPORT_SYMBOL(cont_write_begin);
int block_prepare_write(struct page *page, unsigned from, unsigned to,
*
* We are not allowed to take the i_mutex here so we have to play games to
* protect against truncate races as the page could now be beyond EOF. Because
- * vmtruncate() writes the inode size before removing pages, once we have the
+ * truncate writes the inode size before removing pages, once we have the
* page lock we can determine safely if the page is beyond EOF. If it is not
* beyond EOF, then the page is guaranteed safe against truncation until we
* unlock the page.
}
/*
- * On entry, the page is fully not uptodate.
- * On exit the page is fully uptodate in the areas outside (from,to)
+ * Filesystems implementing the new truncate sequence should use the
+ * _newtrunc postfix variant which won't incorrectly call vmtruncate.
+ * The filesystem needs to handle block truncation upon failure.
*/
-int nobh_write_begin(struct file *file, struct address_space *mapping,
+int nobh_write_begin_newtrunc(struct file *file, struct address_space *mapping,
loff_t pos, unsigned len, unsigned flags,
struct page **pagep, void **fsdata,
get_block_t *get_block)
unlock_page(page);
page_cache_release(page);
*pagep = NULL;
- return block_write_begin(file, mapping, pos, len, flags, pagep,
- fsdata, get_block);
+ return block_write_begin_newtrunc(file, mapping, pos, len,
+ flags, pagep, fsdata, get_block);
}
if (PageMappedToDisk(page))
page_cache_release(page);
*pagep = NULL;
- if (pos + len > inode->i_size)
- vmtruncate(inode, inode->i_size);
+ return ret;
+}
+EXPORT_SYMBOL(nobh_write_begin_newtrunc);
+
+/*
+ * On entry, the page is fully not uptodate.
+ * On exit the page is fully uptodate in the areas outside (from,to)
+ */
+int nobh_write_begin(struct file *file, struct address_space *mapping,
+ loff_t pos, unsigned len, unsigned flags,
+ struct page **pagep, void **fsdata,
+ get_block_t *get_block)
+{
+ int ret;
+
+ ret = nobh_write_begin_newtrunc(file, mapping, pos, len, flags,
+ pagep, fsdata, get_block);
+
+ /*
+ * prepare_write() may have instantiated a few blocks
+ * outside i_size. Trim these off again. Don't need
+ * i_size_read because we hold i_mutex.
+ */
+ if (unlikely(ret)) {
+ loff_t isize = mapping->host->i_size;
+ if (pos + len > isize)
+ vmtruncate(mapping->host, isize);
+ }
return ret;
}
git.openpandora.org / pandora-kernel.git / blobdiff