From: Darrick J. Wong <djwong@xxxxxxxxxx>
Create a new xfile function to discard the page cache that's backing
part of an xfile. The next patch wil use this to drop parts of an xfile
that aren't needed anymore.
Signed-off-by: Darrick J. Wong <djwong@xxxxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
---
fs/xfs/scrub/trace.h | 1 +
fs/xfs/scrub/xfile.c | 12 ++++++++++++
fs/xfs/scrub/xfile.h | 1 +
3 files changed, 14 insertions(+)
diff --git a/fs/xfs/scrub/trace.h b/fs/xfs/scrub/trace.h
index 8d05f2adae3d..7d07912d8f75 100644
--- a/fs/xfs/scrub/trace.h
+++ b/fs/xfs/scrub/trace.h
@@ -948,6 +948,7 @@ DEFINE_XFILE_EVENT(xfile_store);
DEFINE_XFILE_EVENT(xfile_seek_data);
DEFINE_XFILE_EVENT(xfile_get_folio);
DEFINE_XFILE_EVENT(xfile_put_folio);
+DEFINE_XFILE_EVENT(xfile_discard);
TRACE_EVENT(xfarray_create,
TP_PROTO(struct xfarray *xfa, unsigned long long required_capacity),
diff --git a/fs/xfs/scrub/xfile.c b/fs/xfs/scrub/xfile.c
index 8cdd863db585..4e254a0ba003 100644
--- a/fs/xfs/scrub/xfile.c
+++ b/fs/xfs/scrub/xfile.c
@@ -310,3 +310,15 @@ xfile_put_folio(
folio_unlock(folio);
folio_put(folio);
}
+
+/* Discard the page cache that's backing a range of the xfile. */
+void
+xfile_discard(
+ struct xfile *xf,
+ loff_t pos,
+ u64 count)
+{
+ trace_xfile_discard(xf, pos, count);
+
+ shmem_truncate_range(file_inode(xf->file), pos, pos + count - 1);
+}
diff --git a/fs/xfs/scrub/xfile.h b/fs/xfs/scrub/xfile.h
index 76d78dba7e34..8dfbae1fe33a 100644
--- a/fs/xfs/scrub/xfile.h
+++ b/fs/xfs/scrub/xfile.h
@@ -17,6 +17,7 @@ int xfile_load(struct xfile *xf, void *buf, size_t count, loff_t pos);
int xfile_store(struct xfile *xf, const void *buf, size_t count,
loff_t pos);
+void xfile_discard(struct xfile *xf, loff_t pos, u64 count);
loff_t xfile_seek_data(struct xfile *xf, loff_t pos);
#define XFILE_MAX_FOLIO_SIZE (PAGE_SIZE << MAX_PAGECACHE_ORDER)
