// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2000-2005 Silicon Graphics, Inc.
+ * Copyright (c) 2016-2018 Christoph Hellwig.
* All Rights Reserved.
*/
#include "xfs.h"
#include "xfs_bmap_util.h"
#include "xfs_bmap_btree.h"
#include "xfs_reflink.h"
-#include <linux/gfp.h>
-#include <linux/mpage.h>
-#include <linux/pagevec.h>
#include <linux/writeback.h>
/*
*/
struct xfs_writepage_ctx {
struct xfs_bmbt_irec imap;
- bool imap_valid;
unsigned int io_type;
+ unsigned int cow_seq;
struct xfs_ioend *ioend;
- sector_t last_block;
};
-void
-xfs_count_page_state(
- struct page *page,
- int *delalloc,
- int *unwritten)
-{
- struct buffer_head *bh, *head;
-
- *delalloc = *unwritten = 0;
-
- bh = head = page_buffers(page);
- do {
- if (buffer_unwritten(bh))
- (*unwritten) = 1;
- else if (buffer_delay(bh))
- (*delalloc) = 1;
- } while ((bh = bh->b_this_page) != head);
-}
-
struct block_device *
xfs_find_bdev_for_inode(
struct inode *inode)
return mp->m_ddev_targp->bt_daxdev;
}
-/*
- * We're now finished for good with this page. Update the page state via the
- * associated buffer_heads, paying attention to the start and end offsets that
- * we need to process on the page.
- *
- * Note that we open code the action in end_buffer_async_write here so that we
- * only have to iterate over the buffers attached to the page once. This is not
- * only more efficient, but also ensures that we only calls end_page_writeback
- * at the end of the iteration, and thus avoids the pitfall of having the page
- * and buffers potentially freed after every call to end_buffer_async_write.
- */
static void
xfs_finish_page_writeback(
struct inode *inode,
struct bio_vec *bvec,
int error)
{
- struct buffer_head *head = page_buffers(bvec->bv_page), *bh = head;
- bool busy = false;
- unsigned int off = 0;
- unsigned long flags;
-
- ASSERT(bvec->bv_offset < PAGE_SIZE);
- ASSERT((bvec->bv_offset & (i_blocksize(inode) - 1)) == 0);
- ASSERT(bvec->bv_offset + bvec->bv_len <= PAGE_SIZE);
- ASSERT((bvec->bv_len & (i_blocksize(inode) - 1)) == 0);
-
- local_irq_save(flags);
- bit_spin_lock(BH_Uptodate_Lock, &head->b_state);
- do {
- if (off >= bvec->bv_offset &&
- off < bvec->bv_offset + bvec->bv_len) {
- ASSERT(buffer_async_write(bh));
- ASSERT(bh->b_end_io == NULL);
-
- if (error) {
- mark_buffer_write_io_error(bh);
- clear_buffer_uptodate(bh);
- SetPageError(bvec->bv_page);
- } else {
- set_buffer_uptodate(bh);
- }
- clear_buffer_async_write(bh);
- unlock_buffer(bh);
- } else if (buffer_async_write(bh)) {
- ASSERT(buffer_locked(bh));
- busy = true;
- }
- off += bh->b_size;
- } while ((bh = bh->b_this_page) != head);
- bit_spin_unlock(BH_Uptodate_Lock, &head->b_state);
- local_irq_restore(flags);
+ struct iomap_page *iop = to_iomap_page(bvec->bv_page);
+
+ if (error) {
+ SetPageError(bvec->bv_page);
+ mapping_set_error(inode->i_mapping, -EIO);
+ }
+
+ ASSERT(iop || i_blocksize(inode) == PAGE_SIZE);
+ ASSERT(!iop || atomic_read(&iop->write_count) > 0);
- if (!busy)
+ if (!iop || atomic_dec_and_test(&iop->write_count))
end_page_writeback(bvec->bv_page);
}
/* walk each page on bio, ending page IO on them */
bio_for_each_segment_all(bvec, bio, i)
xfs_finish_page_writeback(inode, bvec, error);
-
bio_put(bio);
}
STATIC int
xfs_map_blocks(
+ struct xfs_writepage_ctx *wpc,
struct inode *inode,
- loff_t offset,
- struct xfs_bmbt_irec *imap,
- int type)
+ loff_t offset)
{
struct xfs_inode *ip = XFS_I(inode);
struct xfs_mount *mp = ip->i_mount;
ssize_t count = i_blocksize(inode);
- xfs_fileoff_t offset_fsb, end_fsb;
+ xfs_fileoff_t offset_fsb = XFS_B_TO_FSBT(mp, offset), end_fsb;
+ xfs_fileoff_t cow_fsb = NULLFILEOFF;
+ struct xfs_bmbt_irec imap;
+ int whichfork = XFS_DATA_FORK;
+ struct xfs_iext_cursor icur;
+ bool imap_valid;
int error = 0;
- int bmapi_flags = XFS_BMAPI_ENTIRE;
- int nimaps = 1;
- if (XFS_FORCED_SHUTDOWN(mp))
- return -EIO;
+ /*
+ * We have to make sure the cached mapping is within EOF to protect
+ * against eofblocks trimming on file release leaving us with a stale
+ * mapping. Otherwise, a page for a subsequent file extending buffered
+ * write could get picked up by this writeback cycle and written to the
+ * wrong blocks.
+ *
+ * Note that what we really want here is a generic mapping invalidation
+ * mechanism to protect us from arbitrary extent modifying contexts, not
+ * just eofblocks.
+ */
+ xfs_trim_extent_eof(&wpc->imap, ip);
/*
- * Truncate can race with writeback since writeback doesn't take the
- * iolock and truncate decreases the file size before it starts
- * truncating the pages between new_size and old_size. Therefore, we
- * can end up in the situation where writeback gets a CoW fork mapping
- * but the truncate makes the mapping invalid and we end up in here
- * trying to get a new mapping. Bail out here so that we simply never
- * get a valid mapping and so we drop the write altogether. The page
- * truncation will kill the contents anyway.
+ * COW fork blocks can overlap data fork blocks even if the blocks
+ * aren't shared. COW I/O always takes precedent, so we must always
+ * check for overlap on reflink inodes unless the mapping is already a
+ * COW one, or the COW fork hasn't changed from the last time we looked
+ * at it.
+ *
+ * It's safe to check the COW fork if_seq here without the ILOCK because
+ * we've indirectly protected against concurrent updates: writeback has
+ * the page locked, which prevents concurrent invalidations by reflink
+ * and directio and prevents concurrent buffered writes to the same
+ * page. Changes to if_seq always happen under i_lock, which protects
+ * against concurrent updates and provides a memory barrier on the way
+ * out that ensures that we always see the current value.
*/
- if (type == XFS_IO_COW && offset > i_size_read(inode))
+ imap_valid = offset_fsb >= wpc->imap.br_startoff &&
+ offset_fsb < wpc->imap.br_startoff + wpc->imap.br_blockcount;
+ if (imap_valid &&
+ (!xfs_inode_has_cow_data(ip) ||
+ wpc->io_type == XFS_IO_COW ||
+ wpc->cow_seq == READ_ONCE(ip->i_cowfp->if_seq)))
return 0;
- ASSERT(type != XFS_IO_COW);
- if (type == XFS_IO_UNWRITTEN)
- bmapi_flags |= XFS_BMAPI_IGSTATE;
+ if (XFS_FORCED_SHUTDOWN(mp))
+ return -EIO;
+ /*
+ * If we don't have a valid map, now it's time to get a new one for this
+ * offset. This will convert delayed allocations (including COW ones)
+ * into real extents. If we return without a valid map, it means we
+ * landed in a hole and we skip the block.
+ */
xfs_ilock(ip, XFS_ILOCK_SHARED);
ASSERT(ip->i_d.di_format != XFS_DINODE_FMT_BTREE ||
(ip->i_df.if_flags & XFS_IFEXTENTS));
if (offset > mp->m_super->s_maxbytes - count)
count = mp->m_super->s_maxbytes - offset;
end_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)offset + count);
- offset_fsb = XFS_B_TO_FSBT(mp, offset);
- error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb,
- imap, &nimaps, bmapi_flags);
+
/*
- * Truncate an overwrite extent if there's a pending CoW
- * reservation before the end of this extent. This forces us
- * to come back to writepage to take care of the CoW.
+ * Check if this is offset is covered by a COW extents, and if yes use
+ * it directly instead of looking up anything in the data fork.
*/
- if (nimaps && type == XFS_IO_OVERWRITE)
- xfs_reflink_trim_irec_to_next_cow(ip, offset_fsb, imap);
- xfs_iunlock(ip, XFS_ILOCK_SHARED);
-
- if (error)
- return error;
-
- if (type == XFS_IO_DELALLOC &&
- (!nimaps || isnullstartblock(imap->br_startblock))) {
- error = xfs_iomap_write_allocate(ip, XFS_DATA_FORK, offset,
- imap);
- if (!error)
- trace_xfs_map_blocks_alloc(ip, offset, count, type, imap);
- return error;
- }
-
-#ifdef DEBUG
- if (type == XFS_IO_UNWRITTEN) {
- ASSERT(nimaps);
- ASSERT(imap->br_startblock != HOLESTARTBLOCK);
- ASSERT(imap->br_startblock != DELAYSTARTBLOCK);
+ if (xfs_inode_has_cow_data(ip) &&
+ xfs_iext_lookup_extent(ip, ip->i_cowfp, offset_fsb, &icur, &imap))
+ cow_fsb = imap.br_startoff;
+ if (cow_fsb != NULLFILEOFF && cow_fsb <= offset_fsb) {
+ wpc->cow_seq = READ_ONCE(ip->i_cowfp->if_seq);
+ xfs_iunlock(ip, XFS_ILOCK_SHARED);
+ /*
+ * Truncate can race with writeback since writeback doesn't
+ * take the iolock and truncate decreases the file size before
+ * it starts truncating the pages between new_size and old_size.
+ * Therefore, we can end up in the situation where writeback
+ * gets a CoW fork mapping but the truncate makes the mapping
+ * invalid and we end up in here trying to get a new mapping.
+ * bail out here so that we simply never get a valid mapping
+ * and so we drop the write altogether. The page truncation
+ * will kill the contents anyway.
+ */
+ if (offset > i_size_read(inode)) {
+ wpc->io_type = XFS_IO_HOLE;
+ return 0;
+ }
+ whichfork = XFS_COW_FORK;
+ wpc->io_type = XFS_IO_COW;
+ goto allocate_blocks;
}
-#endif
- if (nimaps)
- trace_xfs_map_blocks_found(ip, offset, count, type, imap);
- return 0;
-}
-
-STATIC bool
-xfs_imap_valid(
- struct inode *inode,
- struct xfs_bmbt_irec *imap,
- xfs_off_t offset)
-{
- offset >>= inode->i_blkbits;
/*
- * We have to make sure the cached mapping is within EOF to protect
- * against eofblocks trimming on file release leaving us with a stale
- * mapping. Otherwise, a page for a subsequent file extending buffered
- * write could get picked up by this writeback cycle and written to the
- * wrong blocks.
- *
- * Note that what we really want here is a generic mapping invalidation
- * mechanism to protect us from arbitrary extent modifying contexts, not
- * just eofblocks.
+ * Map valid and no COW extent in the way? We're done.
*/
- xfs_trim_extent_eof(imap, XFS_I(inode));
-
- return offset >= imap->br_startoff &&
- offset < imap->br_startoff + imap->br_blockcount;
-}
-
-STATIC void
-xfs_start_buffer_writeback(
- struct buffer_head *bh)
-{
- ASSERT(buffer_mapped(bh));
- ASSERT(buffer_locked(bh));
- ASSERT(!buffer_delay(bh));
- ASSERT(!buffer_unwritten(bh));
-
- bh->b_end_io = NULL;
- set_buffer_async_write(bh);
- set_buffer_uptodate(bh);
- clear_buffer_dirty(bh);
-}
-
-STATIC void
-xfs_start_page_writeback(
- struct page *page,
- int clear_dirty)
-{
- ASSERT(PageLocked(page));
- ASSERT(!PageWriteback(page));
+ if (imap_valid) {
+ xfs_iunlock(ip, XFS_ILOCK_SHARED);
+ return 0;
+ }
/*
- * if the page was not fully cleaned, we need to ensure that the higher
- * layers come back to it correctly. That means we need to keep the page
- * dirty, and for WB_SYNC_ALL writeback we need to ensure the
- * PAGECACHE_TAG_TOWRITE index mark is not removed so another attempt to
- * write this page in this writeback sweep will be made.
+ * If we don't have a valid map, now it's time to get a new one for this
+ * offset. This will convert delayed allocations (including COW ones)
+ * into real extents.
*/
- if (clear_dirty) {
- clear_page_dirty_for_io(page);
- set_page_writeback(page);
- } else
- set_page_writeback_keepwrite(page);
+ if (!xfs_iext_lookup_extent(ip, &ip->i_df, offset_fsb, &icur, &imap))
+ imap.br_startoff = end_fsb; /* fake a hole past EOF */
+ xfs_iunlock(ip, XFS_ILOCK_SHARED);
- unlock_page(page);
-}
+ if (imap.br_startoff > offset_fsb) {
+ /* landed in a hole or beyond EOF */
+ imap.br_blockcount = imap.br_startoff - offset_fsb;
+ imap.br_startoff = offset_fsb;
+ imap.br_startblock = HOLESTARTBLOCK;
+ wpc->io_type = XFS_IO_HOLE;
+ } else {
+ /*
+ * Truncate to the next COW extent if there is one. This is the
+ * only opportunity to do this because we can skip COW fork
+ * lookups for the subsequent blocks in the mapping; however,
+ * the requirement to treat the COW range separately remains.
+ */
+ if (cow_fsb != NULLFILEOFF &&
+ cow_fsb < imap.br_startoff + imap.br_blockcount)
+ imap.br_blockcount = cow_fsb - imap.br_startoff;
+
+ if (isnullstartblock(imap.br_startblock)) {
+ /* got a delalloc extent */
+ wpc->io_type = XFS_IO_DELALLOC;
+ goto allocate_blocks;
+ }
-static inline int xfs_bio_add_buffer(struct bio *bio, struct buffer_head *bh)
-{
- return bio_add_page(bio, bh->b_page, bh->b_size, bh_offset(bh));
+ if (imap.br_state == XFS_EXT_UNWRITTEN)
+ wpc->io_type = XFS_IO_UNWRITTEN;
+ else
+ wpc->io_type = XFS_IO_OVERWRITE;
+ }
+
+ wpc->imap = imap;
+ trace_xfs_map_blocks_found(ip, offset, count, wpc->io_type, &imap);
+ return 0;
+allocate_blocks:
+ error = xfs_iomap_write_allocate(ip, whichfork, offset, &imap,
+ &wpc->cow_seq);
+ if (error)
+ return error;
+ ASSERT(whichfork == XFS_COW_FORK || cow_fsb == NULLFILEOFF ||
+ imap.br_startoff + imap.br_blockcount <= cow_fsb);
+ wpc->imap = imap;
+ trace_xfs_map_blocks_alloc(ip, offset, count, wpc->io_type, &imap);
+ return 0;
}
/*
return 0;
}
-static void
-xfs_init_bio_from_bh(
- struct bio *bio,
- struct buffer_head *bh)
-{
- bio->bi_iter.bi_sector = bh->b_blocknr * (bh->b_size >> 9);
- bio_set_dev(bio, bh->b_bdev);
-}
-
static struct xfs_ioend *
xfs_alloc_ioend(
struct inode *inode,
unsigned int type,
xfs_off_t offset,
- struct buffer_head *bh)
+ struct block_device *bdev,
+ sector_t sector)
{
struct xfs_ioend *ioend;
struct bio *bio;
bio = bio_alloc_bioset(GFP_NOFS, BIO_MAX_PAGES, &xfs_ioend_bioset);
- xfs_init_bio_from_bh(bio, bh);
+ bio_set_dev(bio, bdev);
+ bio->bi_iter.bi_sector = sector;
ioend = container_of(bio, struct xfs_ioend, io_inline_bio);
INIT_LIST_HEAD(&ioend->io_list);
xfs_chain_bio(
struct xfs_ioend *ioend,
struct writeback_control *wbc,
- struct buffer_head *bh)
+ struct block_device *bdev,
+ sector_t sector)
{
struct bio *new;
new = bio_alloc(GFP_NOFS, BIO_MAX_PAGES);
- xfs_init_bio_from_bh(new, bh);
-
+ bio_set_dev(new, bdev);
+ new->bi_iter.bi_sector = sector;
bio_chain(ioend->io_bio, new);
bio_get(ioend->io_bio); /* for xfs_destroy_ioend */
ioend->io_bio->bi_opf = REQ_OP_WRITE | wbc_to_write_flags(wbc);
}
/*
- * Test to see if we've been building up a completion structure for
- * earlier buffers -- if so, we try to append to this ioend if we
- * can, otherwise we finish off any current ioend and start another.
- * Return the ioend we finished off so that the caller can submit it
- * once it has finished processing the dirty page.
+ * Test to see if we have an existing ioend structure that we could append to
+ * first, otherwise finish off the current ioend and start another.
*/
STATIC void
xfs_add_to_ioend(
struct inode *inode,
- struct buffer_head *bh,
xfs_off_t offset,
+ struct page *page,
+ struct iomap_page *iop,
struct xfs_writepage_ctx *wpc,
struct writeback_control *wbc,
struct list_head *iolist)
{
+ struct xfs_inode *ip = XFS_I(inode);
+ struct xfs_mount *mp = ip->i_mount;
+ struct block_device *bdev = xfs_find_bdev_for_inode(inode);
+ unsigned len = i_blocksize(inode);
+ unsigned poff = offset & (PAGE_SIZE - 1);
+ sector_t sector;
+
+ sector = xfs_fsb_to_db(ip, wpc->imap.br_startblock) +
+ ((offset - XFS_FSB_TO_B(mp, wpc->imap.br_startoff)) >> 9);
+
if (!wpc->ioend || wpc->io_type != wpc->ioend->io_type ||
- bh->b_blocknr != wpc->last_block + 1 ||
+ sector != bio_end_sector(wpc->ioend->io_bio) ||
offset != wpc->ioend->io_offset + wpc->ioend->io_size) {
if (wpc->ioend)
list_add(&wpc->ioend->io_list, iolist);
- wpc->ioend = xfs_alloc_ioend(inode, wpc->io_type, offset, bh);
+ wpc->ioend = xfs_alloc_ioend(inode, wpc->io_type, offset,
+ bdev, sector);
}
- /*
- * If the buffer doesn't fit into the bio we need to allocate a new
- * one. This shouldn't happen more than once for a given buffer.
- */
- while (xfs_bio_add_buffer(wpc->ioend->io_bio, bh) != bh->b_size)
- xfs_chain_bio(wpc->ioend, wbc, bh);
-
- wpc->ioend->io_size += bh->b_size;
- wpc->last_block = bh->b_blocknr;
- xfs_start_buffer_writeback(bh);
-}
-
-STATIC void
-xfs_map_buffer(
- struct inode *inode,
- struct buffer_head *bh,
- struct xfs_bmbt_irec *imap,
- xfs_off_t offset)
-{
- sector_t bn;
- struct xfs_mount *m = XFS_I(inode)->i_mount;
- xfs_off_t iomap_offset = XFS_FSB_TO_B(m, imap->br_startoff);
- xfs_daddr_t iomap_bn = xfs_fsb_to_db(XFS_I(inode), imap->br_startblock);
-
- ASSERT(imap->br_startblock != HOLESTARTBLOCK);
- ASSERT(imap->br_startblock != DELAYSTARTBLOCK);
-
- bn = (iomap_bn >> (inode->i_blkbits - BBSHIFT)) +
- ((offset - iomap_offset) >> inode->i_blkbits);
-
- ASSERT(bn || XFS_IS_REALTIME_INODE(XFS_I(inode)));
-
- bh->b_blocknr = bn;
- set_buffer_mapped(bh);
-}
-
-STATIC void
-xfs_map_at_offset(
- struct inode *inode,
- struct buffer_head *bh,
- struct xfs_bmbt_irec *imap,
- xfs_off_t offset)
-{
- ASSERT(imap->br_startblock != HOLESTARTBLOCK);
- ASSERT(imap->br_startblock != DELAYSTARTBLOCK);
-
- xfs_map_buffer(inode, bh, imap, offset);
- set_buffer_mapped(bh);
- clear_buffer_delay(bh);
- clear_buffer_unwritten(bh);
-}
-
-/*
- * Test if a given page contains at least one buffer of a given @type.
- * If @check_all_buffers is true, then we walk all the buffers in the page to
- * try to find one of the type passed in. If it is not set, then the caller only
- * needs to check the first buffer on the page for a match.
- */
-STATIC bool
-xfs_check_page_type(
- struct page *page,
- unsigned int type,
- bool check_all_buffers)
-{
- struct buffer_head *bh;
- struct buffer_head *head;
-
- if (PageWriteback(page))
- return false;
- if (!page->mapping)
- return false;
- if (!page_has_buffers(page))
- return false;
-
- bh = head = page_buffers(page);
- do {
- if (buffer_unwritten(bh)) {
- if (type == XFS_IO_UNWRITTEN)
- return true;
- } else if (buffer_delay(bh)) {
- if (type == XFS_IO_DELALLOC)
- return true;
- } else if (buffer_dirty(bh) && buffer_mapped(bh)) {
- if (type == XFS_IO_OVERWRITE)
- return true;
- }
-
- /* If we are only checking the first buffer, we are done now. */
- if (!check_all_buffers)
- break;
- } while ((bh = bh->b_this_page) != head);
+ if (!__bio_try_merge_page(wpc->ioend->io_bio, page, len, poff)) {
+ if (iop)
+ atomic_inc(&iop->write_count);
+ if (bio_full(wpc->ioend->io_bio))
+ xfs_chain_bio(wpc->ioend, wbc, bdev, sector);
+ __bio_add_page(wpc->ioend->io_bio, page, len, poff);
+ }
- return false;
+ wpc->ioend->io_size += len;
}
STATIC void
unsigned int offset,
unsigned int length)
{
- trace_xfs_invalidatepage(page->mapping->host, page, offset,
- length);
-
- /*
- * If we are invalidating the entire page, clear the dirty state from it
- * so that we can check for attempts to release dirty cached pages in
- * xfs_vm_releasepage().
- */
- if (offset == 0 && length >= PAGE_SIZE)
- cancel_dirty_page(page);
- block_invalidatepage(page, offset, length);
+ trace_xfs_invalidatepage(page->mapping->host, page, offset, length);
+ iomap_invalidatepage(page, offset, length);
}
/*
- * If the page has delalloc buffers on it, we need to punch them out before we
- * invalidate the page. If we don't, we leave a stale delalloc mapping on the
- * inode that can trip a BUG() in xfs_get_blocks() later on if a direct IO read
- * is done on that same region - the delalloc extent is returned when none is
- * supposed to be there.
- *
- * We prevent this by truncating away the delalloc regions on the page before
- * invalidating it. Because they are delalloc, we can do this without needing a
- * transaction. Indeed - if we get ENOSPC errors, we have to be able to do this
- * truncation without a transaction as there is no space left for block
- * reservation (typically why we see a ENOSPC in writeback).
+ * If the page has delalloc blocks on it, we need to punch them out before we
+ * invalidate the page. If we don't, we leave a stale delalloc mapping on the
+ * inode that can trip up a later direct I/O read operation on the same region.
*
- * This is not a performance critical path, so for now just do the punching a
- * buffer head at a time.
+ * We prevent this by truncating away the delalloc regions on the page. Because
+ * they are delalloc, we can do this without needing a transaction. Indeed - if
+ * we get ENOSPC errors, we have to be able to do this truncation without a
+ * transaction as there is no space left for block reservation (typically why we
+ * see a ENOSPC in writeback).
*/
STATIC void
xfs_aops_discard_page(
{
struct inode *inode = page->mapping->host;
struct xfs_inode *ip = XFS_I(inode);
- struct buffer_head *bh, *head;
+ struct xfs_mount *mp = ip->i_mount;
loff_t offset = page_offset(page);
+ xfs_fileoff_t start_fsb = XFS_B_TO_FSBT(mp, offset);
+ int error;
- if (!xfs_check_page_type(page, XFS_IO_DELALLOC, true))
- goto out_invalidate;
-
- if (XFS_FORCED_SHUTDOWN(ip->i_mount))
+ if (XFS_FORCED_SHUTDOWN(mp))
goto out_invalidate;
- xfs_alert(ip->i_mount,
+ xfs_alert(mp,
"page discard on page "PTR_FMT", inode 0x%llx, offset %llu.",
page, ip->i_ino, offset);
- xfs_ilock(ip, XFS_ILOCK_EXCL);
- bh = head = page_buffers(page);
- do {
- int error;
- xfs_fileoff_t start_fsb;
-
- if (!buffer_delay(bh))
- goto next_buffer;
-
- start_fsb = XFS_B_TO_FSBT(ip->i_mount, offset);
- error = xfs_bmap_punch_delalloc_range(ip, start_fsb, 1);
- if (error) {
- /* something screwed, just bail */
- if (!XFS_FORCED_SHUTDOWN(ip->i_mount)) {
- xfs_alert(ip->i_mount,
- "page discard unable to remove delalloc mapping.");
- }
- break;
- }
-next_buffer:
- offset += i_blocksize(inode);
-
- } while ((bh = bh->b_this_page) != head);
-
- xfs_iunlock(ip, XFS_ILOCK_EXCL);
+ error = xfs_bmap_punch_delalloc_range(ip, start_fsb,
+ PAGE_SIZE / i_blocksize(inode));
+ if (error && !XFS_FORCED_SHUTDOWN(mp))
+ xfs_alert(mp, "page discard unable to remove delalloc mapping.");
out_invalidate:
xfs_vm_invalidatepage(page, 0, PAGE_SIZE);
- return;
-}
-
-static int
-xfs_map_cow(
- struct xfs_writepage_ctx *wpc,
- struct inode *inode,
- loff_t offset,
- unsigned int *new_type)
-{
- struct xfs_inode *ip = XFS_I(inode);
- struct xfs_bmbt_irec imap;
- bool is_cow = false;
- int error;
-
- /*
- * If we already have a valid COW mapping keep using it.
- */
- if (wpc->io_type == XFS_IO_COW) {
- wpc->imap_valid = xfs_imap_valid(inode, &wpc->imap, offset);
- if (wpc->imap_valid) {
- *new_type = XFS_IO_COW;
- return 0;
- }
- }
-
- /*
- * Else we need to check if there is a COW mapping at this offset.
- */
- xfs_ilock(ip, XFS_ILOCK_SHARED);
- is_cow = xfs_reflink_find_cow_mapping(ip, offset, &imap);
- xfs_iunlock(ip, XFS_ILOCK_SHARED);
-
- if (!is_cow)
- return 0;
-
- /*
- * And if the COW mapping has a delayed extent here we need to
- * allocate real space for it now.
- */
- if (isnullstartblock(imap.br_startblock)) {
- error = xfs_iomap_write_allocate(ip, XFS_COW_FORK, offset,
- &imap);
- if (error)
- return error;
- }
-
- wpc->io_type = *new_type = XFS_IO_COW;
- wpc->imap_valid = true;
- wpc->imap = imap;
- return 0;
}
/*
* We implement an immediate ioend submission policy here to avoid needing to
* chain multiple ioends and hence nest mempool allocations which can violate
* forward progress guarantees we need to provide. The current ioend we are
- * adding buffers to is cached on the writepage context, and if the new buffer
+ * adding blocks to is cached on the writepage context, and if the new block
* does not append to the cached ioend it will create a new ioend and cache that
* instead.
*
uint64_t end_offset)
{
LIST_HEAD(submit_list);
+ struct iomap_page *iop = to_iomap_page(page);
+ unsigned len = i_blocksize(inode);
struct xfs_ioend *ioend, *next;
- struct buffer_head *bh, *head;
- ssize_t len = i_blocksize(inode);
- uint64_t offset;
- int error = 0;
- int count = 0;
- int uptodate = 1;
- unsigned int new_type;
-
- bh = head = page_buffers(page);
- offset = page_offset(page);
- do {
- if (offset >= end_offset)
- break;
- if (!buffer_uptodate(bh))
- uptodate = 0;
+ uint64_t file_offset; /* file offset of page */
+ int error = 0, count = 0, i;
- /*
- * set_page_dirty dirties all buffers in a page, independent
- * of their state. The dirty state however is entirely
- * meaningless for holes (!mapped && uptodate), so skip
- * buffers covering holes here.
- */
- if (!buffer_mapped(bh) && buffer_uptodate(bh)) {
- wpc->imap_valid = false;
- continue;
- }
+ ASSERT(iop || i_blocksize(inode) == PAGE_SIZE);
+ ASSERT(!iop || atomic_read(&iop->write_count) == 0);
- if (buffer_unwritten(bh))
- new_type = XFS_IO_UNWRITTEN;
- else if (buffer_delay(bh))
- new_type = XFS_IO_DELALLOC;
- else if (buffer_uptodate(bh))
- new_type = XFS_IO_OVERWRITE;
- else {
- if (PageUptodate(page))
- ASSERT(buffer_mapped(bh));
- /*
- * This buffer is not uptodate and will not be
- * written to disk. Ensure that we will put any
- * subsequent writeable buffers into a new
- * ioend.
- */
- wpc->imap_valid = false;
+ /*
+ * Walk through the page to find areas to write back. If we run off the
+ * end of the current map or find the current map invalid, grab a new
+ * one.
+ */
+ for (i = 0, file_offset = page_offset(page);
+ i < (PAGE_SIZE >> inode->i_blkbits) && file_offset < end_offset;
+ i++, file_offset += len) {
+ if (iop && !test_bit(i, iop->uptodate))
continue;
- }
- if (xfs_is_reflink_inode(XFS_I(inode))) {
- error = xfs_map_cow(wpc, inode, offset, &new_type);
- if (error)
- goto out;
- }
-
- if (wpc->io_type != new_type) {
- wpc->io_type = new_type;
- wpc->imap_valid = false;
- }
-
- if (wpc->imap_valid)
- wpc->imap_valid = xfs_imap_valid(inode, &wpc->imap,
- offset);
- if (!wpc->imap_valid) {
- error = xfs_map_blocks(inode, offset, &wpc->imap,
- wpc->io_type);
- if (error)
- goto out;
- wpc->imap_valid = xfs_imap_valid(inode, &wpc->imap,
- offset);
- }
- if (wpc->imap_valid) {
- lock_buffer(bh);
- if (wpc->io_type != XFS_IO_OVERWRITE)
- xfs_map_at_offset(inode, bh, &wpc->imap, offset);
- xfs_add_to_ioend(inode, bh, offset, wpc, wbc, &submit_list);
- count++;
- }
-
- } while (offset += len, ((bh = bh->b_this_page) != head));
-
- if (uptodate && bh == head)
- SetPageUptodate(page);
+ error = xfs_map_blocks(wpc, inode, file_offset);
+ if (error)
+ break;
+ if (wpc->io_type == XFS_IO_HOLE)
+ continue;
+ xfs_add_to_ioend(inode, file_offset, page, iop, wpc, wbc,
+ &submit_list);
+ count++;
+ }
ASSERT(wpc->ioend || list_empty(&submit_list));
+ ASSERT(PageLocked(page));
+ ASSERT(!PageWriteback(page));
-out:
/*
- * On error, we have to fail the ioend here because we have locked
- * buffers in the ioend. If we don't do this, we'll deadlock
- * invalidating the page as that tries to lock the buffers on the page.
- * Also, because we may have set pages under writeback, we have to make
- * sure we run IO completion to mark the error state of the IO
- * appropriately, so we can't cancel the ioend directly here. That means
- * we have to mark this page as under writeback if we included any
- * buffers from it in the ioend chain so that completion treats it
- * correctly.
+ * On error, we have to fail the ioend here because we may have set
+ * pages under writeback, we have to make sure we run IO completion to
+ * mark the error state of the IO appropriately, so we can't cancel the
+ * ioend directly here. That means we have to mark this page as under
+ * writeback if we included any blocks from it in the ioend chain so
+ * that completion treats it correctly.
*
* If we didn't include the page in the ioend, the on error we can
* simply discard and unlock it as there are no other users of the page
- * or it's buffers right now. The caller will still need to trigger
- * submission of outstanding ioends on the writepage context so they are
- * treated correctly on error.
+ * now. The caller will still need to trigger submission of outstanding
+ * ioends on the writepage context so they are treated correctly on
+ * error.
*/
- if (count) {
- xfs_start_page_writeback(page, !error);
+ if (unlikely(error)) {
+ if (!count) {
+ xfs_aops_discard_page(page);
+ ClearPageUptodate(page);
+ unlock_page(page);
+ goto done;
+ }
/*
- * Preserve the original error if there was one, otherwise catch
- * submission errors here and propagate into subsequent ioend
- * submissions.
+ * If the page was not fully cleaned, we need to ensure that the
+ * higher layers come back to it correctly. That means we need
+ * to keep the page dirty, and for WB_SYNC_ALL writeback we need
+ * to ensure the PAGECACHE_TAG_TOWRITE index mark is not removed
+ * so another attempt to write this page in this writeback sweep
+ * will be made.
*/
- list_for_each_entry_safe(ioend, next, &submit_list, io_list) {
- int error2;
-
- list_del_init(&ioend->io_list);
- error2 = xfs_submit_ioend(wbc, ioend, error);
- if (error2 && !error)
- error = error2;
- }
- } else if (error) {
- xfs_aops_discard_page(page);
- ClearPageUptodate(page);
- unlock_page(page);
+ set_page_writeback_keepwrite(page);
} else {
- /*
- * We can end up here with no error and nothing to write if we
- * race with a partial page truncate on a sub-page block sized
- * filesystem. In that case we need to mark the page clean.
- */
- xfs_start_page_writeback(page, 1);
- end_page_writeback(page);
+ clear_page_dirty_for_io(page);
+ set_page_writeback(page);
}
+ unlock_page(page);
+
+ /*
+ * Preserve the original error if there was one, otherwise catch
+ * submission errors here and propagate into subsequent ioend
+ * submissions.
+ */
+ list_for_each_entry_safe(ioend, next, &submit_list, io_list) {
+ int error2;
+
+ list_del_init(&ioend->io_list);
+ error2 = xfs_submit_ioend(wbc, ioend, error);
+ if (error2 && !error)
+ error = error2;
+ }
+
+ /*
+ * We can end up here with no error and nothing to write only if we race
+ * with a partial page truncate on a sub-page block sized filesystem.
+ */
+ if (!count)
+ end_page_writeback(page);
+done:
mapping_set_error(page->mapping, error);
return error;
}
* For delalloc space on the page we need to allocate space and flush it.
* For unwritten space on the page we need to start the conversion to
* regular allocated space.
- * For any other dirty buffer heads on the page we should flush them.
*/
STATIC int
xfs_do_writepage(
trace_xfs_writepage(inode, page, 0, 0);
- ASSERT(page_has_buffers(page));
-
/*
* Refuse to write the page out if we are called from reclaim context.
*
xfs_find_bdev_for_inode(mapping->host), wbc);
}
-/*
- * Called to move a page into cleanable state - and from there
- * to be released. The page should already be clean. We always
- * have buffer heads in this call.
- *
- * Returns 1 if the page is ok to release, 0 otherwise.
- */
STATIC int
xfs_vm_releasepage(
struct page *page,
gfp_t gfp_mask)
{
- int delalloc, unwritten;
-
trace_xfs_releasepage(page->mapping->host, page, 0, 0);
-
- /*
- * 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(). Conversely,
- * block_invalidatepage() can send pages that are still marked dirty but
- * otherwise have invalidated buffers.
- *
- * We want to release the latter to avoid unnecessary buildup of the
- * LRU, so xfs_vm_invalidatepage() clears the page dirty flag on pages
- * that are entirely invalidated and need to be released. Hence the
- * only time we should get dirty pages here is through
- * shrink_active_list() and so we can simply skip those now.
- *
- * warn if we've left any lingering delalloc/unwritten buffers on clean
- * or invalidated pages we are about to release.
- */
- if (PageDirty(page))
- return 0;
-
- xfs_count_page_state(page, &delalloc, &unwritten);
-
- if (WARN_ON_ONCE(delalloc))
- return 0;
- if (WARN_ON_ONCE(unwritten))
- return 0;
-
- return try_to_free_buffers(page);
-}
-
-/*
- * If this is O_DIRECT or the mpage code calling tell them how large the mapping
- * is, so that we can avoid repeated get_blocks calls.
- *
- * If the mapping spans EOF, then we have to break the mapping up as the mapping
- * for blocks beyond EOF must be marked new so that sub block regions can be
- * correctly zeroed. We can't do this for mappings within EOF unless the mapping
- * was just allocated or is unwritten, otherwise the callers would overwrite
- * existing data with zeros. Hence we have to split the mapping into a range up
- * to and including EOF, and a second mapping for beyond EOF.
- */
-static void
-xfs_map_trim_size(
- struct inode *inode,
- sector_t iblock,
- struct buffer_head *bh_result,
- struct xfs_bmbt_irec *imap,
- xfs_off_t offset,
- ssize_t size)
-{
- xfs_off_t mapping_size;
-
- mapping_size = imap->br_startoff + imap->br_blockcount - iblock;
- mapping_size <<= inode->i_blkbits;
-
- ASSERT(mapping_size > 0);
- if (mapping_size > size)
- mapping_size = size;
- if (offset < i_size_read(inode) &&
- (xfs_ufsize_t)offset + mapping_size >= i_size_read(inode)) {
- /* limit mapping to block that spans EOF */
- mapping_size = roundup_64(i_size_read(inode) - offset,
- i_blocksize(inode));
- }
- if (mapping_size > LONG_MAX)
- mapping_size = LONG_MAX;
-
- bh_result->b_size = mapping_size;
-}
-
-static int
-xfs_get_blocks(
- struct inode *inode,
- sector_t iblock,
- struct buffer_head *bh_result,
- int create)
-{
- struct xfs_inode *ip = XFS_I(inode);
- struct xfs_mount *mp = ip->i_mount;
- xfs_fileoff_t offset_fsb, end_fsb;
- int error = 0;
- int lockmode = 0;
- struct xfs_bmbt_irec imap;
- int nimaps = 1;
- xfs_off_t offset;
- ssize_t size;
-
- BUG_ON(create);
-
- if (XFS_FORCED_SHUTDOWN(mp))
- return -EIO;
-
- offset = (xfs_off_t)iblock << inode->i_blkbits;
- ASSERT(bh_result->b_size >= i_blocksize(inode));
- size = bh_result->b_size;
-
- if (offset >= i_size_read(inode))
- return 0;
-
- /*
- * Direct I/O is usually done on preallocated files, so try getting
- * a block mapping without an exclusive lock first.
- */
- lockmode = xfs_ilock_data_map_shared(ip);
-
- ASSERT(offset <= mp->m_super->s_maxbytes);
- if (offset > mp->m_super->s_maxbytes - size)
- size = mp->m_super->s_maxbytes - offset;
- end_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)offset + size);
- offset_fsb = XFS_B_TO_FSBT(mp, offset);
-
- error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb, &imap,
- &nimaps, 0);
- if (error)
- goto out_unlock;
- if (!nimaps) {
- trace_xfs_get_blocks_notfound(ip, offset, size);
- goto out_unlock;
- }
-
- trace_xfs_get_blocks_found(ip, offset, size,
- imap.br_state == XFS_EXT_UNWRITTEN ?
- XFS_IO_UNWRITTEN : XFS_IO_OVERWRITE, &imap);
- xfs_iunlock(ip, lockmode);
-
- /* trim mapping down to size requested */
- xfs_map_trim_size(inode, iblock, bh_result, &imap, offset, size);
-
- /*
- * For unwritten extents do not report a disk address in the buffered
- * read case (treat as if we're reading into a hole).
- */
- if (xfs_bmap_is_real_extent(&imap))
- xfs_map_buffer(inode, bh_result, &imap, offset);
-
- /*
- * If this is a realtime file, data may be on a different device.
- * to that pointed to from the buffer_head b_bdev currently.
- */
- bh_result->b_bdev = xfs_find_bdev_for_inode(inode);
- return 0;
-
-out_unlock:
- xfs_iunlock(ip, lockmode);
- return error;
+ return iomap_releasepage(page, gfp_mask);
}
STATIC sector_t
struct page *page)
{
trace_xfs_vm_readpage(page->mapping->host, 1);
- return mpage_readpage(page, xfs_get_blocks);
+ return iomap_readpage(page, &xfs_iomap_ops);
}
STATIC int
unsigned nr_pages)
{
trace_xfs_vm_readpages(mapping->host, nr_pages);
- return mpage_readpages(mapping, pages, nr_pages, xfs_get_blocks);
-}
-
-/*
- * This is basically a copy of __set_page_dirty_buffers() with one
- * small tweak: buffers beyond EOF do not get marked dirty. If we mark them
- * dirty, we'll never be able to clean them because we don't write buffers
- * beyond EOF, and that means we can't invalidate pages that span EOF
- * that have been marked dirty. Further, the dirty state can leak into
- * the file interior if the file is extended, resulting in all sorts of
- * bad things happening as the state does not match the underlying data.
- *
- * XXX: this really indicates that bufferheads in XFS need to die. Warts like
- * this only exist because of bufferheads and how the generic code manages them.
- */
-STATIC int
-xfs_vm_set_page_dirty(
- struct page *page)
-{
- struct address_space *mapping = page->mapping;
- struct inode *inode = mapping->host;
- loff_t end_offset;
- loff_t offset;
- int newly_dirty;
-
- if (unlikely(!mapping))
- return !TestSetPageDirty(page);
-
- end_offset = i_size_read(inode);
- offset = page_offset(page);
-
- spin_lock(&mapping->private_lock);
- if (page_has_buffers(page)) {
- struct buffer_head *head = page_buffers(page);
- struct buffer_head *bh = head;
-
- do {
- if (offset < end_offset)
- set_buffer_dirty(bh);
- bh = bh->b_this_page;
- offset += i_blocksize(inode);
- } while (bh != head);
- }
- /*
- * Lock out page->mem_cgroup migration to keep PageDirty
- * synchronized with per-memcg dirty page counters.
- */
- lock_page_memcg(page);
- newly_dirty = !TestSetPageDirty(page);
- spin_unlock(&mapping->private_lock);
-
- if (newly_dirty)
- __set_page_dirty(page, mapping, 1);
- unlock_page_memcg(page);
- if (newly_dirty)
- __mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
- return newly_dirty;
+ return iomap_readpages(mapping, pages, nr_pages, &xfs_iomap_ops);
}
static int
.readpages = xfs_vm_readpages,
.writepage = xfs_vm_writepage,
.writepages = xfs_vm_writepages,
- .set_page_dirty = xfs_vm_set_page_dirty,
+ .set_page_dirty = iomap_set_page_dirty,
.releasepage = xfs_vm_releasepage,
.invalidatepage = xfs_vm_invalidatepage,
.bmap = xfs_vm_bmap,
.direct_IO = noop_direct_IO,
- .migratepage = buffer_migrate_page,
- .is_partially_uptodate = block_is_partially_uptodate,
+ .migratepage = iomap_migrate_page,
+ .is_partially_uptodate = iomap_is_partially_uptodate,
.error_remove_page = generic_error_remove_page,
.swap_activate = xfs_iomap_swapfile_activate,
};
git.samba.org / sfrench / cifs-2.6.git / blobdiff