[GFS2] Fix unlinked file handling

This patch fixes the way we have been dealing with unlinked,
but still open files. It removes all limits (other than memory
for inodes, as per every other filesystem) on numbers of these
which we can support on GFS2. It also means that (like other
fs) its the responsibility of the last process to close the file
to deallocate the storage, rather than the person who did the
unlinking. Note that with GFS2, those two events might take place
on different nodes.

Also there are a number of other changes:

 o We use the Linux inode subsystem as it was intended to be
used, wrt allocating GFS2 inodes
 o The Linux inode cache is now the point which we use for
local enforcement of only holding one copy of the inode in
core at once (previous to this we used the glock layer).
 o We no longer use the unlinked "special" file. We just ignore it
completely. This makes unlinking more efficient.
 o We now use the 4th block allocation state. The previously unused
state is used to track unlinked but still open inodes.
 o gfs2_inoded is no longer needed
 o Several fields are now no longer needed (and removed) from the in
core struct gfs2_inode
 o Several fields are no longer needed (and removed) from the in core
superblock

There are a number of future possible optimisations and clean ups
which have been made possible by this patch.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

1 files changed, 0 insertions, 459 deletions

diff --git a/fs/gfs2/unlinked.c b/fs/gfs2/unlinked.c
deleted file mode 100644
index b92d73002055..000000000000
--- a/fs/gfs2/unlinked.c
+++ /dev/null
@@ -1,459 +0,0 @@
-/*
- * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
- * Copyright (C) 2004-2006 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/kthread.h>
-#include <linux/gfs2_ondisk.h>
-
-#include "gfs2.h"
-#include "lm_interface.h"
-#include "incore.h"
-#include "bmap.h"
-#include "inode.h"
-#include "meta_io.h"
-#include "trans.h"
-#include "unlinked.h"
-#include "util.h"
-
-static int munge_ondisk(struct gfs2_sbd *sdp, unsigned int slot,
-			struct gfs2_unlinked_tag *ut)
-{
-	struct gfs2_inode *ip = sdp->sd_ut_inode->u.generic_ip;
-	unsigned int block, offset;
-	uint64_t dblock;
-	int new = 0;
-	struct buffer_head *bh;
-	int error;
-	int boundary;
-
-	block = slot / sdp->sd_ut_per_block;
-	offset = slot % sdp->sd_ut_per_block;
-
-	error = gfs2_block_map(ip->i_vnode, block, &new, &dblock, &boundary);
-	if (error)
-		return error;
-	error = gfs2_meta_read(ip->i_gl, dblock, DIO_START | DIO_WAIT, &bh);
-	if (error)
-		return error;
-	if (gfs2_metatype_check(sdp, bh, GFS2_METATYPE_UT)) {
-		error = -EIO;
-		goto out;
-	}
-
-	mutex_lock(&sdp->sd_unlinked_mutex);
-	gfs2_trans_add_bh(ip->i_gl, bh, 1);
-	gfs2_unlinked_tag_out(ut, bh->b_data +
-				  sizeof(struct gfs2_meta_header) +
-				  offset * sizeof(struct gfs2_unlinked_tag));
-	mutex_unlock(&sdp->sd_unlinked_mutex);
-
- out:
-	brelse(bh);
-
-	return error;
-}
-
-static void ul_hash(struct gfs2_sbd *sdp, struct gfs2_unlinked *ul)
-{
-	spin_lock(&sdp->sd_unlinked_spin);
-	list_add(&ul->ul_list, &sdp->sd_unlinked_list);
-	gfs2_assert(sdp, ul->ul_count);
-	ul->ul_count++;
-	atomic_inc(&sdp->sd_unlinked_count);
-	spin_unlock(&sdp->sd_unlinked_spin);
-}
-
-static void ul_unhash(struct gfs2_sbd *sdp, struct gfs2_unlinked *ul)
-{
-	spin_lock(&sdp->sd_unlinked_spin);
-	list_del_init(&ul->ul_list);
-	gfs2_assert(sdp, ul->ul_count > 1);
-	ul->ul_count--;
-	gfs2_assert_warn(sdp, atomic_read(&sdp->sd_unlinked_count) > 0);
-	atomic_dec(&sdp->sd_unlinked_count);
-	spin_unlock(&sdp->sd_unlinked_spin);
-}
-
-static struct gfs2_unlinked *ul_fish(struct gfs2_sbd *sdp)
-{
-	struct list_head *head;
-	struct gfs2_unlinked *ul;
-	int found = 0;
-
-	if (sdp->sd_vfs->s_flags & MS_RDONLY)
-		return NULL;
-
-	spin_lock(&sdp->sd_unlinked_spin);
-
-	head = &sdp->sd_unlinked_list;
-
-	list_for_each_entry(ul, head, ul_list) {
-		if (test_bit(ULF_LOCKED, &ul->ul_flags))
-			continue;
-
-		list_move_tail(&ul->ul_list, head);
-		ul->ul_count++;
-		set_bit(ULF_LOCKED, &ul->ul_flags);
-		found = 1;
-
-		break;
-	}
-
-	if (!found)
-		ul = NULL;
-
-	spin_unlock(&sdp->sd_unlinked_spin);
-
-	return ul;
-}
-
-/**
- * enforce_limit - limit the number of inodes waiting to be deallocated
- * @sdp: the filesystem
- *
- * Returns: errno
- */
-
-static void enforce_limit(struct gfs2_sbd *sdp)
-{
-	unsigned int tries = 0, min = 0;
-	int error;
-
-	if (atomic_read(&sdp->sd_unlinked_count) <
-	    gfs2_tune_get(sdp, gt_ilimit))
-		return;
-
-	tries = gfs2_tune_get(sdp, gt_ilimit_tries);
-	min = gfs2_tune_get(sdp, gt_ilimit_min);
-
-	while (tries--) {
-		struct gfs2_unlinked *ul = ul_fish(sdp);
-		if (!ul)
-			break;
-		error = gfs2_inode_dealloc(sdp, ul);
-		gfs2_unlinked_put(sdp, ul);
-
-		if (!error) {
-			if (!--min)
-				break;
-		} else if (error != 1)
-			break;
-	}
-}
-
-static struct gfs2_unlinked *ul_alloc(struct gfs2_sbd *sdp)
-{
-	struct gfs2_unlinked *ul;
-
-	ul = kzalloc(sizeof(struct gfs2_unlinked), GFP_KERNEL);
-	if (ul) {
-		INIT_LIST_HEAD(&ul->ul_list);
-		ul->ul_count = 1;
-		set_bit(ULF_LOCKED, &ul->ul_flags);
-	}
-
-	return ul;
-}
-
-int gfs2_unlinked_get(struct gfs2_sbd *sdp, struct gfs2_unlinked **ul)
-{
-	unsigned int c, o = 0, b;
-	unsigned char byte = 0;
-
-	enforce_limit(sdp);
-
-	*ul = ul_alloc(sdp);
-	if (!*ul)
-		return -ENOMEM;
-
-	spin_lock(&sdp->sd_unlinked_spin);
-
-	for (c = 0; c < sdp->sd_unlinked_chunks; c++)
-		for (o = 0; o < PAGE_SIZE; o++) {
-			byte = sdp->sd_unlinked_bitmap[c][o];
-			if (byte != 0xFF)
-				goto found;
-		}
-
-	goto fail;
-
-found:
-	for (b = 0; b < 8; b++)
-		if (!(byte & (1 << b)))
-			break;
-	(*ul)->ul_slot = c * (8 * PAGE_SIZE) + o * 8 + b;
-
-	if ((*ul)->ul_slot >= sdp->sd_unlinked_slots)
-		goto fail;
-
-	sdp->sd_unlinked_bitmap[c][o] |= 1 << b;
-
-	spin_unlock(&sdp->sd_unlinked_spin);
-
-	return 0;
-
-fail:
-	spin_unlock(&sdp->sd_unlinked_spin);
-	kfree(*ul);
-	return -ENOSPC;
-}
-
-void gfs2_unlinked_put(struct gfs2_sbd *sdp, struct gfs2_unlinked *ul)
-{
-	gfs2_assert_warn(sdp, test_and_clear_bit(ULF_LOCKED, &ul->ul_flags));
-
-	spin_lock(&sdp->sd_unlinked_spin);
-	gfs2_assert(sdp, ul->ul_count);
-	ul->ul_count--;
-	if (!ul->ul_count) {
-		gfs2_icbit_munge(sdp, sdp->sd_unlinked_bitmap, ul->ul_slot, 0);
-		spin_unlock(&sdp->sd_unlinked_spin);
-		kfree(ul);
-	} else
-		spin_unlock(&sdp->sd_unlinked_spin);
-}
-
-int gfs2_unlinked_ondisk_add(struct gfs2_sbd *sdp, struct gfs2_unlinked *ul)
-{
-	int error;
-
-	gfs2_assert_warn(sdp, test_bit(ULF_LOCKED, &ul->ul_flags));
-	gfs2_assert_warn(sdp, list_empty(&ul->ul_list));
-
-	error = munge_ondisk(sdp, ul->ul_slot, &ul->ul_ut);
-	if (!error)
-		ul_hash(sdp, ul);
-
-	return error;
-}
-
-int gfs2_unlinked_ondisk_munge(struct gfs2_sbd *sdp, struct gfs2_unlinked *ul)
-{
-	int error;
-
-	gfs2_assert_warn(sdp, test_bit(ULF_LOCKED, &ul->ul_flags));
-	gfs2_assert_warn(sdp, !list_empty(&ul->ul_list));
-
-	error = munge_ondisk(sdp, ul->ul_slot, &ul->ul_ut);
-
-	return error;
-}
-
-int gfs2_unlinked_ondisk_rm(struct gfs2_sbd *sdp, struct gfs2_unlinked *ul)
-{
-	struct gfs2_unlinked_tag ut;
-	int error;
-
-	gfs2_assert_warn(sdp, test_bit(ULF_LOCKED, &ul->ul_flags));
-	gfs2_assert_warn(sdp, !list_empty(&ul->ul_list));
-
-	memset(&ut, 0, sizeof(struct gfs2_unlinked_tag));
-
-	error = munge_ondisk(sdp, ul->ul_slot, &ut);
-	if (error)
-		return error;
-
-	ul_unhash(sdp, ul);
-
-	return 0;
-}
-
-/**
- * gfs2_unlinked_dealloc - Go through the list of inodes to be deallocated
- * @sdp: the filesystem
- *
- * Returns: errno
- */
-
-int gfs2_unlinked_dealloc(struct gfs2_sbd *sdp)
-{
-	unsigned int hits, strikes;
-	int error;
-
-	for (;;) {
-		hits = 0;
-		strikes = 0;
-
-		for (;;) {
-			struct gfs2_unlinked *ul = ul_fish(sdp);
-			if (!ul)
-				return 0;
-			error = gfs2_inode_dealloc(sdp, ul);
-			gfs2_unlinked_put(sdp, ul);
-
-			if (!error) {
-				hits++;
-				if (strikes)
-					strikes--;
-			} else if (error == 1) {
-				strikes++;
-				if (strikes >=
-				    atomic_read(&sdp->sd_unlinked_count)) {
-					error = 0;
-					break;
-				}
-			} else
-				return error;
-		}
-
-		if (!hits || kthread_should_stop())
-			break;
-
-		cond_resched();
-	}
-
-	return 0;
-}
-
-int gfs2_unlinked_init(struct gfs2_sbd *sdp)
-{
-	struct gfs2_inode *ip = sdp->sd_ut_inode->u.generic_ip;
-	unsigned int blocks = ip->i_di.di_size >> sdp->sd_sb.sb_bsize_shift;
-	unsigned int x, slot = 0;
-	unsigned int found = 0;
-	uint64_t dblock;
-	uint32_t extlen = 0;
-	int error;
-
-	if (!ip->i_di.di_size ||
-	    ip->i_di.di_size > (64 << 20) ||
-	    ip->i_di.di_size & (sdp->sd_sb.sb_bsize - 1)) {
-		gfs2_consist_inode(ip);
-		return -EIO;		
-	}
-	sdp->sd_unlinked_slots = blocks * sdp->sd_ut_per_block;
-	sdp->sd_unlinked_chunks = DIV_ROUND_UP(sdp->sd_unlinked_slots,
-					       8 * PAGE_SIZE);
-
-	error = -ENOMEM;
-
-	sdp->sd_unlinked_bitmap = kcalloc(sdp->sd_unlinked_chunks,
-					  sizeof(unsigned char *),
-					  GFP_KERNEL);
-	if (!sdp->sd_unlinked_bitmap)
-		return error;
-
-	for (x = 0; x < sdp->sd_unlinked_chunks; x++) {
-		sdp->sd_unlinked_bitmap[x] = kzalloc(PAGE_SIZE, GFP_KERNEL);
-		if (!sdp->sd_unlinked_bitmap[x])
-			goto fail;
-	}
-
-	for (x = 0; x < blocks; x++) {
-		struct buffer_head *bh;
-		unsigned int y;
-
-		if (!extlen) {
-			int new = 0;
-			error = gfs2_extent_map(ip->i_vnode, x, &new, &dblock, &extlen);
-			if (error)
-				goto fail;
-		}
-		gfs2_meta_ra(ip->i_gl, dblock, extlen);
-		error = gfs2_meta_read(ip->i_gl, dblock, DIO_START | DIO_WAIT,
-				       &bh);
-		if (error)
-			goto fail;
-		error = -EIO;
-		if (gfs2_metatype_check(sdp, bh, GFS2_METATYPE_UT)) {
-			brelse(bh);
-			goto fail;
-		}
-
-		for (y = 0;
-		     y < sdp->sd_ut_per_block && slot < sdp->sd_unlinked_slots;
-		     y++, slot++) {
-			struct gfs2_unlinked_tag ut;
-			struct gfs2_unlinked *ul;
-
-			gfs2_unlinked_tag_in(&ut, bh->b_data +
-					  sizeof(struct gfs2_meta_header) +
-					  y * sizeof(struct gfs2_unlinked_tag));
-			if (!ut.ut_inum.no_addr)
-				continue;
-
-			error = -ENOMEM;
-			ul = ul_alloc(sdp);
-			if (!ul) {
-				brelse(bh);
-				goto fail;
-			}
-			ul->ul_ut = ut;
-			ul->ul_slot = slot;
-
-			spin_lock(&sdp->sd_unlinked_spin);
-			gfs2_icbit_munge(sdp, sdp->sd_unlinked_bitmap, slot, 1);
-			spin_unlock(&sdp->sd_unlinked_spin);
-			ul_hash(sdp, ul);
-
-			gfs2_unlinked_put(sdp, ul);
-			found++;
-		}
-
-		brelse(bh);
-		dblock++;
-		extlen--;
-	}
-
-	if (found)
-		fs_info(sdp, "found %u unlinked inodes\n", found);
-
-	return 0;
-
-fail:
-	gfs2_unlinked_cleanup(sdp);
-	return error;
-}
-
-/**
- * gfs2_unlinked_cleanup - get rid of any extra struct gfs2_unlinked structures
- * @sdp: the filesystem
- *
- */
-
-void gfs2_unlinked_cleanup(struct gfs2_sbd *sdp)
-{
-	struct list_head *head = &sdp->sd_unlinked_list;
-	struct gfs2_unlinked *ul;
-	unsigned int x;
-
-	spin_lock(&sdp->sd_unlinked_spin);
-	while (!list_empty(head)) {
-		ul = list_entry(head->next, struct gfs2_unlinked, ul_list);
-
-		if (ul->ul_count > 1) {
-			list_move_tail(&ul->ul_list, head);
-			spin_unlock(&sdp->sd_unlinked_spin);
-			schedule();
-			spin_lock(&sdp->sd_unlinked_spin);
-			continue;
-		}
-
-		list_del_init(&ul->ul_list);
-		atomic_dec(&sdp->sd_unlinked_count);
-
-		gfs2_assert_warn(sdp, ul->ul_count == 1);
-		gfs2_assert_warn(sdp, !test_bit(ULF_LOCKED, &ul->ul_flags));
-		kfree(ul);
-	}
-	spin_unlock(&sdp->sd_unlinked_spin);
-
-	gfs2_assert_warn(sdp, !atomic_read(&sdp->sd_unlinked_count));
-
-	if (sdp->sd_unlinked_bitmap) {
-		for (x = 0; x < sdp->sd_unlinked_chunks; x++)
-			kfree(sdp->sd_unlinked_bitmap[x]);
-		kfree(sdp->sd_unlinked_bitmap);
-	}
-}
-