xfs: add file_{get,put}_folio

Add helper similar to file_{get,set}_page, but which deal with folios
and don't allocate new folio unless explicitly asked to, which map
to shmem_get_folio instead of calling into the aops.

Signed-off-by: "Darrick J. Wong" <djwong@kernel.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Kent Overstreet <kent.overstreet@linux.dev>
Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>

diff --git a/fs/xfs/scrub/trace.h b/fs/xfs/scrub/trace.h
index 0327cab606b0706c92eff30c2c2f201a79d41146..c61fa7a95ef522c5e38ca379261550f62ca65ca8 100644 (file)
--- a/fs/xfs/scrub/trace.h
+++ b/fs/xfs/scrub/trace.h
@@ -908,6 +908,8 @@ DEFINE_XFILE_EVENT(xfile_store);
 DEFINE_XFILE_EVENT(xfile_seek_data);
 DEFINE_XFILE_EVENT(xfile_get_page);
 DEFINE_XFILE_EVENT(xfile_put_page);
+DEFINE_XFILE_EVENT(xfile_get_folio);
+DEFINE_XFILE_EVENT(xfile_put_folio);
 
 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 2229f0b7f9ca49563fce1a477db008d68df241f8..0cab9d529365bbed7ef6a575ce4eefbf350330f1 100644 (file)
--- a/fs/xfs/scrub/xfile.c
+++ b/fs/xfs/scrub/xfile.c
@@ -340,3 +340,77 @@ xfile_put_page(
                return -EIO;
        return 0;
 }
+
+/*
+ * Grab the (locked) folio for a memory object.  The object cannot span a folio
+ * boundary.  Returns the locked folio if successful, NULL if there was no
+ * folio or it didn't cover the range requested, or an ERR_PTR on failure.
+ */
+struct folio *
+xfile_get_folio(
+       struct xfile            *xf,
+       loff_t                  pos,
+       size_t                  len,
+       unsigned int            flags)
+{
+       struct inode            *inode = file_inode(xf->file);
+       struct folio            *folio = NULL;
+       unsigned int            pflags;
+       int                     error;
+
+       if (inode->i_sb->s_maxbytes - pos < len)
+               return ERR_PTR(-ENOMEM);
+
+       trace_xfile_get_folio(xf, pos, len);
+
+       /*
+        * Increase the file size first so that shmem_get_folio(..., SGP_CACHE),
+        * actually allocates a folio instead of erroring out.
+        */
+       if ((flags & XFILE_ALLOC) && pos + len > i_size_read(inode))
+               i_size_write(inode, pos + len);
+
+       pflags = memalloc_nofs_save();
+       error = shmem_get_folio(inode, pos >> PAGE_SHIFT, &folio,
+                       (flags & XFILE_ALLOC) ? SGP_CACHE : SGP_READ);
+       memalloc_nofs_restore(pflags);
+       if (error)
+               return ERR_PTR(error);
+
+       if (!folio)
+               return NULL;
+
+       if (len > folio_size(folio) - offset_in_folio(folio, pos)) {
+               folio_unlock(folio);
+               folio_put(folio);
+               return NULL;
+       }
+
+       if (filemap_check_wb_err(inode->i_mapping, 0)) {
+               folio_unlock(folio);
+               folio_put(folio);
+               return ERR_PTR(-EIO);
+       }
+
+       /*
+        * Mark the folio dirty so that it won't be reclaimed once we drop the
+        * (potentially last) reference in xfile_put_folio.
+        */
+       if (flags & XFILE_ALLOC)
+               folio_set_dirty(folio);
+       return folio;
+}
+
+/*
+ * Release the (locked) folio for a memory object.
+ */
+void
+xfile_put_folio(
+       struct xfile            *xf,
+       struct folio            *folio)
+{
+       trace_xfile_put_folio(xf, folio_pos(folio), folio_size(folio));
+
+       folio_unlock(folio);
+       folio_put(folio);
+}

diff --git a/fs/xfs/scrub/xfile.h b/fs/xfs/scrub/xfile.h
index 465b10f492b66d331b9185e8e91dae8d310d2635..afb75e9fbaf2650cad5df212f50a9bff9ce1f7bd 100644 (file)
--- a/fs/xfs/scrub/xfile.h
+++ b/fs/xfs/scrub/xfile.h
@@ -39,4 +39,11 @@ int xfile_get_page(struct xfile *xf, loff_t offset, unsigned int len,
                struct xfile_page *xbuf);
 int xfile_put_page(struct xfile *xf, struct xfile_page *xbuf);
 
+#define XFILE_MAX_FOLIO_SIZE   (PAGE_SIZE << MAX_PAGECACHE_ORDER)
+
+#define XFILE_ALLOC            (1 << 0) /* allocate folio if not present */
+struct folio *xfile_get_folio(struct xfile *xf, loff_t offset, size_t len,
+               unsigned int flags);
+void xfile_put_folio(struct xfile *xf, struct folio *folio);
+
 #endif /* __XFS_SCRUB_XFILE_H__ */