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authorChristoph Hellwig <hch@lst.de>2016-09-19 10:12:45 +1000
committerDave Chinner <david@fromorbit.com>2016-09-19 10:12:45 +1000
commit5f4e5752a8a3a72c79514def2ad9fc7cd410ce2e (patch)
tree943edac57e87caabeaece086af13c8a0c6cef60f /fs/iomap.c
parentea78d80866ce375defb2fdd1c8a3aafec95e0f85 (diff)
downloadlinux-5f4e5752a8a3a72c79514def2ad9fc7cd410ce2e.tar.bz2
fs: add iomap_file_dirty
Originally-From: Christoph Hellwig <hch@lst.de> This function uses the iomap infrastructure to re-write all pages in a given range. This is useful for doing a copy-up of COW ranges, and might be useful for scrubbing in the future. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
Diffstat (limited to 'fs/iomap.c')
-rw-r--r--fs/iomap.c82
1 files changed, 82 insertions, 0 deletions
diff --git a/fs/iomap.c b/fs/iomap.c
index 706270f21b35..e9b3f991c2d8 100644
--- a/fs/iomap.c
+++ b/fs/iomap.c
@@ -252,6 +252,88 @@ iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *iter,
}
EXPORT_SYMBOL_GPL(iomap_file_buffered_write);
+static struct page *
+__iomap_read_page(struct inode *inode, loff_t offset)
+{
+ struct address_space *mapping = inode->i_mapping;
+ struct page *page;
+
+ page = read_mapping_page(mapping, offset >> PAGE_SHIFT, NULL);
+ if (IS_ERR(page))
+ return page;
+ if (!PageUptodate(page)) {
+ put_page(page);
+ return ERR_PTR(-EIO);
+ }
+ return page;
+}
+
+static loff_t
+iomap_dirty_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
+ struct iomap *iomap)
+{
+ long status = 0;
+ ssize_t written = 0;
+
+ do {
+ struct page *page, *rpage;
+ unsigned long offset; /* Offset into pagecache page */
+ unsigned long bytes; /* Bytes to write to page */
+
+ offset = (pos & (PAGE_SIZE - 1));
+ bytes = min_t(unsigned long, PAGE_SIZE - offset, length);
+
+ rpage = __iomap_read_page(inode, pos);
+ if (IS_ERR(rpage))
+ return PTR_ERR(rpage);
+
+ status = iomap_write_begin(inode, pos, bytes,
+ AOP_FLAG_NOFS | AOP_FLAG_UNINTERRUPTIBLE,
+ &page, iomap);
+ put_page(rpage);
+ if (unlikely(status))
+ return status;
+
+ WARN_ON_ONCE(!PageUptodate(page));
+
+ status = iomap_write_end(inode, pos, bytes, bytes, page);
+ if (unlikely(status <= 0)) {
+ if (WARN_ON_ONCE(status == 0))
+ return -EIO;
+ return status;
+ }
+
+ cond_resched();
+
+ pos += status;
+ written += status;
+ length -= status;
+
+ balance_dirty_pages_ratelimited(inode->i_mapping);
+ } while (length);
+
+ return written;
+}
+
+int
+iomap_file_dirty(struct inode *inode, loff_t pos, loff_t len,
+ struct iomap_ops *ops)
+{
+ loff_t ret;
+
+ while (len) {
+ ret = iomap_apply(inode, pos, len, IOMAP_WRITE, ops, NULL,
+ iomap_dirty_actor);
+ if (ret <= 0)
+ return ret;
+ pos += ret;
+ len -= ret;
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(iomap_file_dirty);
+
static int iomap_zero(struct inode *inode, loff_t pos, unsigned offset,
unsigned bytes, struct iomap *iomap)
{