1 files changed, 582 insertions, 0 deletions

diff --git a/fs/gfs2/ops_address.c b/fs/gfs2/ops_address.c
new file mode 100644
index 000000000000..005c2522a879
--- /dev/null
+++ b/fs/gfs2/ops_address.c
@@ -0,0 +1,582 @@
+/*
+ * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
+ * Copyright (C) 2004-2005 Red Hat, Inc.  All rights reserved.
+ *
+ * This copyrighted material is made available to anyone wishing to use,
+ * modify, copy, or redistribute it subject to the terms and conditions
+ * of the GNU General Public License v.2.
+ */
+
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/completion.h>
+#include <linux/buffer_head.h>
+#include <linux/pagemap.h>
+#include <linux/mpage.h>
+#include <linux/fs.h>
+#include <linux/gfs2_ondisk.h>
+#include <asm/semaphore.h>
+
+#include "gfs2.h"
+#include "lm_interface.h"
+#include "incore.h"
+#include "bmap.h"
+#include "glock.h"
+#include "inode.h"
+#include "log.h"
+#include "meta_io.h"
+#include "ops_address.h"
+#include "page.h"
+#include "quota.h"
+#include "trans.h"
+#include "rgrp.h"
+#include "ops_file.h"
+#include "util.h"
+
+/**
+ * gfs2_get_block - Fills in a buffer head with details about a block
+ * @inode: The inode
+ * @lblock: The block number to look up
+ * @bh_result: The buffer head to return the result in
+ * @create: Non-zero if we may add block to the file
+ *
+ * Returns: errno
+ */
+
+int gfs2_get_block(struct inode *inode, sector_t lblock,
+	           struct buffer_head *bh_result, int create)
+{
+	struct gfs2_inode *ip = inode->u.generic_ip;
+	int new = create;
+	uint64_t dblock;
+	int error;
+
+	error = gfs2_block_map(ip, lblock, &new, &dblock, NULL);
+	if (error)
+		return error;
+
+	if (!dblock)
+		return 0;
+
+	map_bh(bh_result, inode->i_sb, dblock);
+	if (new)
+		set_buffer_new(bh_result);
+
+	return 0;
+}
+
+/**
+ * get_block_noalloc - Fills in a buffer head with details about a block
+ * @inode: The inode
+ * @lblock: The block number to look up
+ * @bh_result: The buffer head to return the result in
+ * @create: Non-zero if we may add block to the file
+ *
+ * Returns: errno
+ */
+
+static int get_block_noalloc(struct inode *inode, sector_t lblock,
+			     struct buffer_head *bh_result, int create)
+{
+	struct gfs2_inode *ip = inode->u.generic_ip;
+	int new = 0;
+	uint64_t dblock;
+	int error;
+
+	error = gfs2_block_map(ip, lblock, &new, &dblock, NULL);
+	if (error)
+		return error;
+
+	if (dblock)
+		map_bh(bh_result, inode->i_sb, dblock);
+	else if (gfs2_assert_withdraw(ip->i_sbd, !create))
+		error = -EIO;
+
+	return error;
+}
+
+/**
+ * gfs2_writepage - Write complete page
+ * @page: Page to write
+ *
+ * Returns: errno
+ *
+ * Some of this is copied from block_write_full_page() although we still
+ * call it to do most of the work.
+ */
+
+static int gfs2_writepage(struct page *page, struct writeback_control *wbc)
+{
+	struct inode *inode = page->mapping->host;
+	struct gfs2_inode *ip = page->mapping->host->u.generic_ip;
+	struct gfs2_sbd *sdp = ip->i_sbd;
+	loff_t i_size = i_size_read(inode);
+	pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT;
+	unsigned offset;
+	int error;
+	int done_trans = 0;
+
+	if (gfs2_assert_withdraw(sdp, gfs2_glock_is_held_excl(ip->i_gl))) {
+		unlock_page(page);
+		return -EIO;
+	}
+	if (current->journal_info)
+		goto out_ignore;
+
+	/* Is the page fully outside i_size? (truncate in progress) */
+        offset = i_size & (PAGE_CACHE_SIZE-1);
+	if (page->index >= end_index+1 || !offset) {
+		page->mapping->a_ops->invalidatepage(page, 0);
+		unlock_page(page);
+		return 0; /* don't care */
+	}
+
+	if (sdp->sd_args.ar_data == GFS2_DATA_ORDERED || gfs2_is_jdata(ip)) {
+		error = gfs2_trans_begin(sdp, RES_DINODE + 1, 0);
+		if (error)
+			goto out_ignore;
+		gfs2_page_add_databufs(ip, page, 0, sdp->sd_vfs->s_blocksize-1);
+		done_trans = 1;
+	}
+	error = block_write_full_page(page, get_block_noalloc, wbc);
+	if (done_trans)
+		gfs2_trans_end(sdp);
+	gfs2_meta_cache_flush(ip);
+	return error;
+
+out_ignore:
+	redirty_page_for_writepage(wbc, page);
+	unlock_page(page);
+	return 0;
+}
+
+/**
+ * stuffed_readpage - Fill in a Linux page with stuffed file data
+ * @ip: the inode
+ * @page: the page
+ *
+ * Returns: errno
+ */
+
+static int stuffed_readpage(struct gfs2_inode *ip, struct page *page)
+{
+	struct buffer_head *dibh;
+	void *kaddr;
+	int error;
+
+	error = gfs2_meta_inode_buffer(ip, &dibh);
+	if (error)
+		return error;
+
+	kaddr = kmap_atomic(page, KM_USER0);
+	memcpy((char *)kaddr,
+	       dibh->b_data + sizeof(struct gfs2_dinode),
+	       ip->i_di.di_size);
+	memset((char *)kaddr + ip->i_di.di_size,
+	       0,
+	       PAGE_CACHE_SIZE - ip->i_di.di_size);
+	kunmap_atomic(page, KM_USER0);
+
+	brelse(dibh);
+
+	SetPageUptodate(page);
+
+	return 0;
+}
+
+static int zero_readpage(struct page *page)
+{
+	void *kaddr;
+
+	kaddr = kmap_atomic(page, KM_USER0);
+	memset(kaddr, 0, PAGE_CACHE_SIZE);
+	kunmap_atomic(page, KM_USER0);
+
+	SetPageUptodate(page);
+	unlock_page(page);
+
+	return 0;
+}
+
+/**
+ * gfs2_readpage - readpage with locking
+ * @file: The file to read a page for. N.B. This may be NULL if we are
+ * reading an internal file.
+ * @page: The page to read
+ *
+ * Returns: errno
+ */
+
+static int gfs2_readpage(struct file *file, struct page *page)
+{
+	struct gfs2_inode *ip = page->mapping->host->u.generic_ip;
+	struct gfs2_sbd *sdp = ip->i_sbd;
+	struct gfs2_holder gh;
+	int error;
+
+	if (file != &gfs2_internal_file_sentinal) {
+		gfs2_holder_init(ip->i_gl, LM_ST_SHARED, GL_ATIME|GL_AOP, &gh);
+		error = gfs2_glock_nq_m_atime(1, &gh);
+		if (error)
+			goto out_unlock;
+	}
+
+	if (gfs2_is_stuffed(ip)) {
+		if (!page->index) {
+			error = stuffed_readpage(ip, page);
+			unlock_page(page);
+		} else
+			error = zero_readpage(page);
+	} else
+		error = mpage_readpage(page, gfs2_get_block);
+
+	if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
+		error = -EIO;
+
+	if (file != &gfs2_internal_file_sentinal) {
+		gfs2_glock_dq_m(1, &gh);
+		gfs2_holder_uninit(&gh);
+	}
+out:
+	return error;
+out_unlock:
+	unlock_page(page);
+	goto out;
+}
+
+/**
+ * gfs2_prepare_write - Prepare to write a page to a file
+ * @file: The file to write to
+ * @page: The page which is to be prepared for writing
+ * @from: From (byte range within page)
+ * @to: To (byte range within page)
+ *
+ * Returns: errno
+ */
+
+static int gfs2_prepare_write(struct file *file, struct page *page,
+			      unsigned from, unsigned to)
+{
+	struct gfs2_inode *ip = page->mapping->host->u.generic_ip;
+	struct gfs2_sbd *sdp = ip->i_sbd;
+	unsigned int data_blocks, ind_blocks, rblocks;
+	int alloc_required;
+	int error = 0;
+	loff_t pos = ((loff_t)page->index << PAGE_CACHE_SHIFT) + from;
+	loff_t end = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to;
+	struct gfs2_alloc *al;
+
+	gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, GL_ATIME|GL_AOP, &ip->i_gh);
+	error = gfs2_glock_nq_m_atime(1, &ip->i_gh);
+	if (error)
+		goto out_uninit;
+
+	gfs2_write_calc_reserv(ip, to - from, &data_blocks, &ind_blocks);
+
+	error = gfs2_write_alloc_required(ip, pos, from - to, &alloc_required);
+	if (error)
+		goto out_unlock;
+
+
+	if (alloc_required) {
+		al = gfs2_alloc_get(ip);
+
+		error = gfs2_quota_lock(ip, NO_QUOTA_CHANGE, NO_QUOTA_CHANGE);
+		if (error)
+			goto out_alloc_put;
+
+		error = gfs2_quota_check(ip, ip->i_di.di_uid, ip->i_di.di_gid);
+		if (error)
+			goto out_qunlock;
+
+		al->al_requested = data_blocks + ind_blocks;
+		error = gfs2_inplace_reserve(ip);
+		if (error)
+			goto out_qunlock;
+	}
+
+	rblocks = RES_DINODE + ind_blocks;
+	if (gfs2_is_jdata(ip))
+		rblocks += data_blocks ? data_blocks : 1;
+	if (ind_blocks || data_blocks)
+		rblocks += RES_STATFS + RES_QUOTA;
+
+	error = gfs2_trans_begin(sdp, rblocks, 0);
+	if (error)
+		goto out;
+
+	if (gfs2_is_stuffed(ip)) {
+		if (end > sdp->sd_sb.sb_bsize - sizeof(struct gfs2_dinode)) {
+			error = gfs2_unstuff_dinode(ip, gfs2_unstuffer_page,
+						    page);
+			if (error == 0)
+				goto prepare_write;
+		} else if (!PageUptodate(page))
+			error = stuffed_readpage(ip, page);
+		goto out;
+	}
+
+prepare_write:
+	error = block_prepare_write(page, from, to, gfs2_get_block);
+
+out:
+	if (error) {
+		gfs2_trans_end(sdp);
+		if (alloc_required) {
+			gfs2_inplace_release(ip);
+out_qunlock:
+			gfs2_quota_unlock(ip);
+out_alloc_put:
+			gfs2_alloc_put(ip);
+		}
+out_unlock:
+		gfs2_glock_dq_m(1, &ip->i_gh);
+out_uninit:
+		gfs2_holder_uninit(&ip->i_gh);
+	}
+
+	return error;
+}
+
+/**
+ * gfs2_commit_write - Commit write to a file
+ * @file: The file to write to
+ * @page: The page containing the data
+ * @from: From (byte range within page)
+ * @to: To (byte range within page)
+ *
+ * Returns: errno
+ */
+
+static int gfs2_commit_write(struct file *file, struct page *page,
+			     unsigned from, unsigned to)
+{
+	struct inode *inode = page->mapping->host;
+	struct gfs2_inode *ip = inode->u.generic_ip;
+	struct gfs2_sbd *sdp = ip->i_sbd;
+	int error = -EOPNOTSUPP;
+	struct buffer_head *dibh;
+	struct gfs2_alloc *al = &ip->i_alloc;;
+
+	if (gfs2_assert_withdraw(sdp, gfs2_glock_is_locked_by_me(ip->i_gl)))
+                goto fail_nounlock;
+
+	error = gfs2_meta_inode_buffer(ip, &dibh);
+	if (error)
+		goto fail_endtrans;
+
+	gfs2_trans_add_bh(ip->i_gl, dibh, 1);
+
+	if (gfs2_is_stuffed(ip)) {
+		uint64_t file_size;
+		void *kaddr;
+
+		file_size = ((uint64_t)page->index << PAGE_CACHE_SHIFT) + to;
+
+		kaddr = kmap_atomic(page, KM_USER0);
+		memcpy(dibh->b_data + sizeof(struct gfs2_dinode) + from,
+		       (char *)kaddr + from, to - from);
+		kunmap_atomic(page, KM_USER0);
+
+		SetPageUptodate(page);
+
+		if (inode->i_size < file_size)
+			i_size_write(inode, file_size);
+	} else {
+		if (sdp->sd_args.ar_data == GFS2_DATA_ORDERED ||
+		    gfs2_is_jdata(ip))
+			gfs2_page_add_databufs(ip, page, from, to);
+		error = generic_commit_write(file, page, from, to);
+		if (error)
+			goto fail;
+	}
+
+	if (ip->i_di.di_size < inode->i_size)
+		ip->i_di.di_size = inode->i_size;
+
+	gfs2_dinode_out(&ip->i_di, dibh->b_data);
+	brelse(dibh);
+	gfs2_trans_end(sdp);
+	if (al->al_requested) {
+		gfs2_inplace_release(ip);
+		gfs2_quota_unlock(ip);
+		gfs2_alloc_put(ip);
+	}
+	gfs2_glock_dq_m(1, &ip->i_gh);
+	gfs2_holder_uninit(&ip->i_gh);
+	return 0;
+
+fail:
+	brelse(dibh);
+fail_endtrans:
+	gfs2_trans_end(sdp);
+	if (al->al_requested) {
+		gfs2_inplace_release(ip);
+		gfs2_quota_unlock(ip);
+		gfs2_alloc_put(ip);
+	}
+	gfs2_glock_dq_m(1, &ip->i_gh);
+	gfs2_holder_uninit(&ip->i_gh);
+fail_nounlock:
+	ClearPageUptodate(page);
+	return error;
+}
+
+/**
+ * gfs2_bmap - Block map function
+ * @mapping: Address space info
+ * @lblock: The block to map
+ *
+ * Returns: The disk address for the block or 0 on hole or error
+ */
+
+static sector_t gfs2_bmap(struct address_space *mapping, sector_t lblock)
+{
+	struct gfs2_inode *ip = mapping->host->u.generic_ip;
+	struct gfs2_holder i_gh;
+	sector_t dblock = 0;
+	int error;
+
+	error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, LM_FLAG_ANY, &i_gh);
+	if (error)
+		return 0;
+
+	if (!gfs2_is_stuffed(ip))
+		dblock = generic_block_bmap(mapping, lblock, gfs2_get_block);
+
+	gfs2_glock_dq_uninit(&i_gh);
+
+	return dblock;
+}
+
+static void discard_buffer(struct gfs2_sbd *sdp, struct buffer_head *bh)
+{
+	struct gfs2_bufdata *bd;
+
+	gfs2_log_lock(sdp);
+	bd = bh->b_private;
+	if (bd) {
+		bd->bd_bh = NULL;
+		bh->b_private = NULL;
+		gfs2_log_unlock(sdp);
+		brelse(bh);
+	} else
+		gfs2_log_unlock(sdp);
+
+	lock_buffer(bh);
+	clear_buffer_dirty(bh);
+	bh->b_bdev = NULL;
+	clear_buffer_mapped(bh);
+	clear_buffer_req(bh);
+	clear_buffer_new(bh);
+	clear_buffer_delay(bh);
+	unlock_buffer(bh);
+}
+
+static void gfs2_invalidatepage(struct page *page, unsigned long offset)
+{
+	struct gfs2_sbd *sdp = page->mapping->host->i_sb->s_fs_info;
+	struct buffer_head *head, *bh, *next;
+	unsigned int curr_off = 0;
+
+	BUG_ON(!PageLocked(page));
+	if (!page_has_buffers(page))
+		return;
+
+	bh = head = page_buffers(page);
+	do {
+		unsigned int next_off = curr_off + bh->b_size;
+		next = bh->b_this_page;
+
+		if (offset <= curr_off)
+			discard_buffer(sdp, bh);
+
+		curr_off = next_off;
+		bh = next;
+	} while (bh != head);
+
+	if (!offset)
+		try_to_release_page(page, 0);
+
+	return;
+}
+
+static ssize_t gfs2_direct_IO_write(struct kiocb *iocb, const struct iovec *iov,
+				    loff_t offset, unsigned long nr_segs)
+{
+	struct file *file = iocb->ki_filp;
+	struct inode *inode = file->f_mapping->host;
+	struct gfs2_inode *ip = inode->u.generic_ip;
+	struct gfs2_holder gh;
+	int rv;
+
+	/*
+	 * Shared lock, even though its write, since we do no allocation
+	 * on this path. All we need change is atime.
+	 */
+	gfs2_holder_init(ip->i_gl, LM_ST_SHARED, GL_ATIME, &gh);
+	rv = gfs2_glock_nq_m_atime(1, &gh);
+	if (rv)
+		goto out;
+
+	/*
+	 * Should we return an error here? I can't see that O_DIRECT for
+	 * a journaled file makes any sense. For now we'll silently fall
+	 * back to buffered I/O, likewise we do the same for stuffed
+	 * files since they are (a) small and (b) unaligned.
+	 */
+	if (gfs2_is_jdata(ip))
+		goto out;
+
+	if (gfs2_is_stuffed(ip))
+		goto out;
+
+	rv = __blockdev_direct_IO(WRITE, iocb, inode, inode->i_sb->s_bdev,
+				  iov, offset, nr_segs, gfs2_get_block,
+				  NULL, DIO_OWN_LOCKING);
+out:
+	gfs2_glock_dq_m(1, &gh);
+	gfs2_holder_uninit(&gh);
+
+	return rv;
+}
+
+/**
+ * gfs2_direct_IO
+ *
+ * This is called with a shared lock already held for the read path.
+ * Currently, no locks are held when the write path is called.
+ */
+static ssize_t gfs2_direct_IO(int rw, struct kiocb *iocb,
+			      const struct iovec *iov, loff_t offset,
+			      unsigned long nr_segs)
+{
+	struct file *file = iocb->ki_filp;
+	struct inode *inode = file->f_mapping->host;
+	struct gfs2_inode *ip = inode->u.generic_ip;
+	struct gfs2_sbd *sdp = ip->i_sbd;
+
+	if (rw == WRITE)
+		return gfs2_direct_IO_write(iocb, iov, offset, nr_segs);
+
+	if (gfs2_assert_warn(sdp, gfs2_glock_is_locked_by_me(ip->i_gl)) ||
+	    gfs2_assert_warn(sdp, !gfs2_is_stuffed(ip)))
+		return -EINVAL;
+
+	return __blockdev_direct_IO(READ, iocb, inode, inode->i_sb->s_bdev, iov,
+			 	    offset, nr_segs, gfs2_get_block, NULL,
+				    DIO_OWN_LOCKING);
+}
+
+struct address_space_operations gfs2_file_aops = {
+	.writepage = gfs2_writepage,
+	.readpage = gfs2_readpage,
+	.sync_page = block_sync_page,
+	.prepare_write = gfs2_prepare_write,
+	.commit_write = gfs2_commit_write,
+	.bmap = gfs2_bmap,
+	.invalidatepage = gfs2_invalidatepage,
+	.direct_IO = gfs2_direct_IO,
+};
+