#include <linux/iomap.h>
#include <linux/uaccess.h>
#include <linux/gfp.h>
+#include <linux/migrate.h>
#include <linux/mm.h>
#include <linux/mm_inline.h>
#include <linux/swap.h>
return (iomap->addr + pos - iomap->offset) >> SECTOR_SHIFT;
}
+static struct iomap_page *
+iomap_page_create(struct inode *inode, struct page *page)
+{
+ struct iomap_page *iop = to_iomap_page(page);
+
+ if (iop || i_blocksize(inode) == PAGE_SIZE)
+ return iop;
+
+ iop = kmalloc(sizeof(*iop), GFP_NOFS | __GFP_NOFAIL);
+ atomic_set(&iop->read_count, 0);
+ atomic_set(&iop->write_count, 0);
+ bitmap_zero(iop->uptodate, PAGE_SIZE / SECTOR_SIZE);
+ set_page_private(page, (unsigned long)iop);
+ SetPagePrivate(page);
+ return iop;
+}
+
+static void
+iomap_page_release(struct page *page)
+{
+ struct iomap_page *iop = to_iomap_page(page);
+
+ if (!iop)
+ return;
+ WARN_ON_ONCE(atomic_read(&iop->read_count));
+ WARN_ON_ONCE(atomic_read(&iop->write_count));
+ ClearPagePrivate(page);
+ set_page_private(page, 0);
+ kfree(iop);
+}
+
+/*
+ * Calculate the range inside the page that we actually need to read.
+ */
+static void
+iomap_adjust_read_range(struct inode *inode, struct iomap_page *iop,
+ loff_t *pos, loff_t length, unsigned *offp, unsigned *lenp)
+{
+ unsigned block_bits = inode->i_blkbits;
+ unsigned block_size = (1 << block_bits);
+ unsigned poff = *pos & (PAGE_SIZE - 1);
+ unsigned plen = min_t(loff_t, PAGE_SIZE - poff, length);
+ unsigned first = poff >> block_bits;
+ unsigned last = (poff + plen - 1) >> block_bits;
+ unsigned end = (i_size_read(inode) & (PAGE_SIZE - 1)) >> block_bits;
+
+ /*
+ * If the block size is smaller than the page size we need to check the
+ * per-block uptodate status and adjust the offset and length if needed
+ * to avoid reading in already uptodate ranges.
+ */
+ if (iop) {
+ unsigned int i;
+
+ /* move forward for each leading block marked uptodate */
+ for (i = first; i <= last; i++) {
+ if (!test_bit(i, iop->uptodate))
+ break;
+ *pos += block_size;
+ poff += block_size;
+ plen -= block_size;
+ first++;
+ }
+
+ /* truncate len if we find any trailing uptodate block(s) */
+ for ( ; i <= last; i++) {
+ if (test_bit(i, iop->uptodate)) {
+ plen -= (last - i + 1) * block_size;
+ last = i - 1;
+ break;
+ }
+ }
+ }
+
+ /*
+ * If the extent spans the block that contains the i_size we need to
+ * handle both halves separately so that we properly zero data in the
+ * page cache for blocks that are entirely outside of i_size.
+ */
+ if (first <= end && last > end)
+ plen -= (last - end) * block_size;
+
+ *offp = poff;
+ *lenp = plen;
+}
+
+static void
+iomap_set_range_uptodate(struct page *page, unsigned off, unsigned len)
+{
+ struct iomap_page *iop = to_iomap_page(page);
+ struct inode *inode = page->mapping->host;
+ unsigned first = off >> inode->i_blkbits;
+ unsigned last = (off + len - 1) >> inode->i_blkbits;
+ unsigned int i;
+ bool uptodate = true;
+
+ if (iop) {
+ for (i = 0; i < PAGE_SIZE / i_blocksize(inode); i++) {
+ if (i >= first && i <= last)
+ set_bit(i, iop->uptodate);
+ else if (!test_bit(i, iop->uptodate))
+ uptodate = false;
+ }
+ }
+
+ if (uptodate && !PageError(page))
+ SetPageUptodate(page);
+}
+
+static void
+iomap_read_finish(struct iomap_page *iop, struct page *page)
+{
+ if (!iop || atomic_dec_and_test(&iop->read_count))
+ unlock_page(page);
+}
+
+static void
+iomap_read_page_end_io(struct bio_vec *bvec, int error)
+{
+ struct page *page = bvec->bv_page;
+ struct iomap_page *iop = to_iomap_page(page);
+
+ if (unlikely(error)) {
+ ClearPageUptodate(page);
+ SetPageError(page);
+ } else {
+ iomap_set_range_uptodate(page, bvec->bv_offset, bvec->bv_len);
+ }
+
+ iomap_read_finish(iop, page);
+}
+
static void
iomap_read_inline_data(struct inode *inode, struct page *page,
struct iomap *iomap)
int i;
bio_for_each_segment_all(bvec, bio, i)
- page_endio(bvec->bv_page, false, error);
+ iomap_read_page_end_io(bvec, error);
bio_put(bio);
}
{
struct iomap_readpage_ctx *ctx = data;
struct page *page = ctx->cur_page;
- unsigned poff = pos & (PAGE_SIZE - 1);
- unsigned plen = min_t(loff_t, PAGE_SIZE - poff, length);
+ struct iomap_page *iop = iomap_page_create(inode, page);
bool is_contig = false;
+ loff_t orig_pos = pos;
+ unsigned poff, plen;
sector_t sector;
if (iomap->type == IOMAP_INLINE) {
return PAGE_SIZE;
}
- /* we don't support blocksize < PAGE_SIZE quite yet. */
- WARN_ON_ONCE(pos != page_offset(page));
- WARN_ON_ONCE(plen != PAGE_SIZE);
+ /* zero post-eof blocks as the page may be mapped */
+ iomap_adjust_read_range(inode, iop, &pos, length, &poff, &plen);
+ if (plen == 0)
+ goto done;
if (iomap->type != IOMAP_MAPPED || pos >= i_size_read(inode)) {
zero_user(page, poff, plen);
- SetPageUptodate(page);
+ iomap_set_range_uptodate(page, poff, plen);
goto done;
}
is_contig = true;
}
+ /*
+ * If we start a new segment we need to increase the read count, and we
+ * need to do so before submitting any previous full bio to make sure
+ * that we don't prematurely unlock the page.
+ */
+ if (iop)
+ atomic_inc(&iop->read_count);
+
if (!ctx->bio || !is_contig || bio_full(ctx->bio)) {
gfp_t gfp = mapping_gfp_constraint(page->mapping, GFP_KERNEL);
int nr_vecs = (length + PAGE_SIZE - 1) >> PAGE_SHIFT;
__bio_add_page(ctx->bio, page, plen, poff);
done:
- return plen;
+ /*
+ * Move the caller beyond our range so that it keeps making progress.
+ * For that we have to include any leading non-uptodate ranges, but
+ * we can skip trailing ones as they will be handled in the next
+ * iteration.
+ */
+ return pos - orig_pos + plen;
}
int
unsigned poff;
loff_t ret;
- WARN_ON_ONCE(page_has_buffers(page));
-
for (poff = 0; poff < PAGE_SIZE; poff += ret) {
ret = iomap_apply(inode, page_offset(page) + poff,
PAGE_SIZE - poff, 0, ops, &ctx,
}
EXPORT_SYMBOL_GPL(iomap_readpages);
+int
+iomap_is_partially_uptodate(struct page *page, unsigned long from,
+ unsigned long count)
+{
+ struct iomap_page *iop = to_iomap_page(page);
+ struct inode *inode = page->mapping->host;
+ unsigned first = from >> inode->i_blkbits;
+ unsigned last = (from + count - 1) >> inode->i_blkbits;
+ unsigned i;
+
+ if (iop) {
+ for (i = first; i <= last; i++)
+ if (!test_bit(i, iop->uptodate))
+ return 0;
+ return 1;
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(iomap_is_partially_uptodate);
+
+int
+iomap_releasepage(struct page *page, gfp_t gfp_mask)
+{
+ /*
+ * mm accommodates an old ext3 case where clean pages might not have had
+ * the dirty bit cleared. Thus, it can send actual dirty pages to
+ * ->releasepage() via shrink_active_list(), skip those here.
+ */
+ if (PageDirty(page) || PageWriteback(page))
+ return 0;
+ iomap_page_release(page);
+ return 1;
+}
+EXPORT_SYMBOL_GPL(iomap_releasepage);
+
+void
+iomap_invalidatepage(struct page *page, unsigned int offset, unsigned int len)
+{
+ /*
+ * If we are invalidating the entire page, clear the dirty state from it
+ * and release it to avoid unnecessary buildup of the LRU.
+ */
+ if (offset == 0 && len == PAGE_SIZE) {
+ WARN_ON_ONCE(PageWriteback(page));
+ cancel_dirty_page(page);
+ iomap_page_release(page);
+ }
+}
+EXPORT_SYMBOL_GPL(iomap_invalidatepage);
+
+#ifdef CONFIG_MIGRATION
+int
+iomap_migrate_page(struct address_space *mapping, struct page *newpage,
+ struct page *page, enum migrate_mode mode)
+{
+ int ret;
+
+ ret = migrate_page_move_mapping(mapping, newpage, page, NULL, mode, 0);
+ if (ret != MIGRATEPAGE_SUCCESS)
+ return ret;
+
+ if (page_has_private(page)) {
+ ClearPagePrivate(page);
+ set_page_private(newpage, page_private(page));
+ set_page_private(page, 0);
+ SetPagePrivate(newpage);
+ }
+
+ if (mode != MIGRATE_SYNC_NO_COPY)
+ migrate_page_copy(newpage, page);
+ else
+ migrate_page_states(newpage, page);
+ return MIGRATEPAGE_SUCCESS;
+}
+EXPORT_SYMBOL_GPL(iomap_migrate_page);
+#endif /* CONFIG_MIGRATION */
+
static void
iomap_write_failed(struct inode *inode, loff_t pos, unsigned len)
{
if (iomap->type != IOMAP_MAPPED || block_start >= i_size_read(inode)) {
zero_user_segments(page, poff, from, to, poff + plen);
+ iomap_set_range_uptodate(page, poff, plen);
return 0;
}
__iomap_write_begin(struct inode *inode, loff_t pos, unsigned len,
struct page *page, struct iomap *iomap)
{
+ struct iomap_page *iop = iomap_page_create(inode, page);
loff_t block_size = i_blocksize(inode);
loff_t block_start = pos & ~(block_size - 1);
loff_t block_end = (pos + len + block_size - 1) & ~(block_size - 1);
- unsigned poff = block_start & (PAGE_SIZE - 1);
- unsigned plen = min_t(loff_t, PAGE_SIZE - poff, block_end - block_start);
- unsigned from = pos & (PAGE_SIZE - 1), to = from + len;
-
- WARN_ON_ONCE(i_blocksize(inode) < PAGE_SIZE);
+ unsigned from = pos & (PAGE_SIZE - 1), to = from + len, poff, plen;
+ int status = 0;
if (PageUptodate(page))
return 0;
- if (from <= poff && to >= poff + plen)
- return 0;
- return iomap_read_page_sync(inode, block_start, page,
- poff, plen, from, to, iomap);
+
+ do {
+ iomap_adjust_read_range(inode, iop, &block_start,
+ block_end - block_start, &poff, &plen);
+ if (plen == 0)
+ break;
+
+ if ((from > poff && from < poff + plen) ||
+ (to > poff && to < poff + plen)) {
+ status = iomap_read_page_sync(inode, block_start, page,
+ poff, plen, from, to, iomap);
+ if (status)
+ break;
+ }
+
+ } while ((block_start += plen) < block_end);
+
+ return status;
}
static int
if (unlikely(copied < len && !PageUptodate(page))) {
copied = 0;
} else {
- SetPageUptodate(page);
+ iomap_set_range_uptodate(page, pos & (PAGE_SIZE - 1), len);
iomap_set_page_dirty(page);
}
return __generic_write_end(inode, pos, copied, page);
block_commit_write(page, 0, length);
} else {
WARN_ON_ONCE(!PageUptodate(page));
- WARN_ON_ONCE(i_blocksize(inode) < PAGE_SIZE);
+ iomap_page_create(inode, page);
}
return length;
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