* Copyright (C) 2010 Red Hat, Inc.
* Copyright (c) 2016-2021 Christoph Hellwig.
*/
-#include <linux/module.h>
-#include <linux/compiler.h>
#include <linux/fs.h>
#include <linux/iomap.h>
#include "trace.h"
-/*
- * Execute a iomap write on a segment of the mapping that spans a
- * contiguous range of pages that have identical block mapping state.
- *
- * This avoids the need to map pages individually, do individual allocations
- * for each page and most importantly avoid the need for filesystem specific
- * locking per page. Instead, all the operations are amortised over the entire
- * range of pages. It is assumed that the filesystems will lock whatever
- * resources they require in the iomap_begin call, and release them in the
- * iomap_end call.
- */
-loff_t
-iomap_apply(struct inode *inode, loff_t pos, loff_t length, unsigned flags,
- const struct iomap_ops *ops, void *data, iomap_actor_t actor)
-{
- struct iomap iomap = { .type = IOMAP_HOLE };
- struct iomap srcmap = { .type = IOMAP_HOLE };
- loff_t written = 0, ret;
- u64 end;
-
- trace_iomap_apply(inode, pos, length, flags, ops, actor, _RET_IP_);
-
- /*
- * Need to map a range from start position for length bytes. This can
- * span multiple pages - it is only guaranteed to return a range of a
- * single type of pages (e.g. all into a hole, all mapped or all
- * unwritten). Failure at this point has nothing to undo.
- *
- * If allocation is required for this range, reserve the space now so
- * that the allocation is guaranteed to succeed later on. Once we copy
- * the data into the page cache pages, then we cannot fail otherwise we
- * expose transient stale data. If the reserve fails, we can safely
- * back out at this point as there is nothing to undo.
- */
- ret = ops->iomap_begin(inode, pos, length, flags, &iomap, &srcmap);
- if (ret)
- return ret;
- if (WARN_ON(iomap.offset > pos)) {
- written = -EIO;
- goto out;
- }
- if (WARN_ON(iomap.length == 0)) {
- written = -EIO;
- goto out;
- }
-
- trace_iomap_apply_dstmap(inode, &iomap);
- if (srcmap.type != IOMAP_HOLE)
- trace_iomap_apply_srcmap(inode, &srcmap);
-
- /*
- * Cut down the length to the one actually provided by the filesystem,
- * as it might not be able to give us the whole size that we requested.
- */
- end = iomap.offset + iomap.length;
- if (srcmap.type != IOMAP_HOLE)
- end = min(end, srcmap.offset + srcmap.length);
- if (pos + length > end)
- length = end - pos;
-
- /*
- * Now that we have guaranteed that the space allocation will succeed,
- * we can do the copy-in page by page without having to worry about
- * failures exposing transient data.
- *
- * To support COW operations, we read in data for partially blocks from
- * the srcmap if the file system filled it in. In that case we the
- * length needs to be limited to the earlier of the ends of the iomaps.
- * If the file system did not provide a srcmap we pass in the normal
- * iomap into the actors so that they don't need to have special
- * handling for the two cases.
- */
- written = actor(inode, pos, length, data, &iomap,
- srcmap.type != IOMAP_HOLE ? &srcmap : &iomap);
-
-out:
- /*
- * Now the data has been copied, commit the range we've copied. This
- * should not fail unless the filesystem has had a fatal error.
- */
- if (ops->iomap_end) {
- ret = ops->iomap_end(inode, pos, length,
- written > 0 ? written : 0,
- flags, &iomap);
- }
-
- return written ? written : ret;
-}
-
static inline int iomap_iter_advance(struct iomap_iter *iter)
{
/* handle the previous iteration (if any) */
DEFINE_EVENT(iomap_class, name, \
TP_PROTO(struct inode *inode, struct iomap *iomap), \
TP_ARGS(inode, iomap))
-DEFINE_IOMAP_EVENT(iomap_apply_dstmap);
-DEFINE_IOMAP_EVENT(iomap_apply_srcmap);
DEFINE_IOMAP_EVENT(iomap_iter_dstmap);
DEFINE_IOMAP_EVENT(iomap_iter_srcmap);
-TRACE_EVENT(iomap_apply,
- TP_PROTO(struct inode *inode, loff_t pos, loff_t length,
- unsigned int flags, const void *ops, void *actor,
- unsigned long caller),
- TP_ARGS(inode, pos, length, flags, ops, actor, caller),
- TP_STRUCT__entry(
- __field(dev_t, dev)
- __field(u64, ino)
- __field(loff_t, pos)
- __field(loff_t, length)
- __field(unsigned int, flags)
- __field(const void *, ops)
- __field(void *, actor)
- __field(unsigned long, caller)
- ),
- TP_fast_assign(
- __entry->dev = inode->i_sb->s_dev;
- __entry->ino = inode->i_ino;
- __entry->pos = pos;
- __entry->length = length;
- __entry->flags = flags;
- __entry->ops = ops;
- __entry->actor = actor;
- __entry->caller = caller;
- ),
- TP_printk("dev %d:%d ino 0x%llx pos %lld length %lld flags %s (0x%x) "
- "ops %ps caller %pS actor %ps",
- MAJOR(__entry->dev), MINOR(__entry->dev),
- __entry->ino,
- __entry->pos,
- __entry->length,
- __print_flags(__entry->flags, "|", IOMAP_FLAGS_STRINGS),
- __entry->flags,
- __entry->ops,
- (void *)__entry->caller,
- __entry->actor)
-);
-
TRACE_EVENT(iomap_iter,
TP_PROTO(struct iomap_iter *iter, const void *ops,
unsigned long caller),