Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 2326 insertions, 0 deletions

diff --git a/mm/shmem.c b/mm/shmem.c
new file mode 100644
index 00000000000..61574b81d97
--- /dev/null
+++ b/mm/shmem.c
@@ -0,0 +1,2326 @@
+/*
+ * Resizable virtual memory filesystem for Linux.
+ *
+ * Copyright (C) 2000 Linus Torvalds.
+ *		 2000 Transmeta Corp.
+ *		 2000-2001 Christoph Rohland
+ *		 2000-2001 SAP AG
+ *		 2002 Red Hat Inc.
+ * Copyright (C) 2002-2004 Hugh Dickins.
+ * Copyright (C) 2002-2004 VERITAS Software Corporation.
+ * Copyright (C) 2004 Andi Kleen, SuSE Labs
+ *
+ * Extended attribute support for tmpfs:
+ * Copyright (c) 2004, Luke Kenneth Casson Leighton <lkcl@lkcl.net>
+ * Copyright (c) 2004 Red Hat, Inc., James Morris <jmorris@redhat.com>
+ *
+ * This file is released under the GPL.
+ */
+
+/*
+ * This virtual memory filesystem is heavily based on the ramfs. It
+ * extends ramfs by the ability to use swap and honor resource limits
+ * which makes it a completely usable filesystem.
+ */
+
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/devfs_fs_kernel.h>
+#include <linux/fs.h>
+#include <linux/mm.h>
+#include <linux/mman.h>
+#include <linux/file.h>
+#include <linux/swap.h>
+#include <linux/pagemap.h>
+#include <linux/string.h>
+#include <linux/slab.h>
+#include <linux/backing-dev.h>
+#include <linux/shmem_fs.h>
+#include <linux/mount.h>
+#include <linux/writeback.h>
+#include <linux/vfs.h>
+#include <linux/blkdev.h>
+#include <linux/security.h>
+#include <linux/swapops.h>
+#include <linux/mempolicy.h>
+#include <linux/namei.h>
+#include <linux/xattr.h>
+#include <asm/uaccess.h>
+#include <asm/div64.h>
+#include <asm/pgtable.h>
+
+/* This magic number is used in glibc for posix shared memory */
+#define TMPFS_MAGIC	0x01021994
+
+#define ENTRIES_PER_PAGE (PAGE_CACHE_SIZE/sizeof(unsigned long))
+#define ENTRIES_PER_PAGEPAGE (ENTRIES_PER_PAGE*ENTRIES_PER_PAGE)
+#define BLOCKS_PER_PAGE  (PAGE_CACHE_SIZE/512)
+
+#define SHMEM_MAX_INDEX  (SHMEM_NR_DIRECT + (ENTRIES_PER_PAGEPAGE/2) * (ENTRIES_PER_PAGE+1))
+#define SHMEM_MAX_BYTES  ((unsigned long long)SHMEM_MAX_INDEX << PAGE_CACHE_SHIFT)
+
+#define VM_ACCT(size)    (PAGE_CACHE_ALIGN(size) >> PAGE_SHIFT)
+
+/* info->flags needs VM_flags to handle pagein/truncate races efficiently */
+#define SHMEM_PAGEIN	 VM_READ
+#define SHMEM_TRUNCATE	 VM_WRITE
+
+/* Definition to limit shmem_truncate's steps between cond_rescheds */
+#define LATENCY_LIMIT	 64
+
+/* Pretend that each entry is of this size in directory's i_size */
+#define BOGO_DIRENT_SIZE 20
+
+/* Keep swapped page count in private field of indirect struct page */
+#define nr_swapped		private
+
+/* Flag allocation requirements to shmem_getpage and shmem_swp_alloc */
+enum sgp_type {
+	SGP_QUICK,	/* don't try more than file page cache lookup */
+	SGP_READ,	/* don't exceed i_size, don't allocate page */
+	SGP_CACHE,	/* don't exceed i_size, may allocate page */
+	SGP_WRITE,	/* may exceed i_size, may allocate page */
+};
+
+static int shmem_getpage(struct inode *inode, unsigned long idx,
+			 struct page **pagep, enum sgp_type sgp, int *type);
+
+static inline struct page *shmem_dir_alloc(unsigned int gfp_mask)
+{
+	/*
+	 * The above definition of ENTRIES_PER_PAGE, and the use of
+	 * BLOCKS_PER_PAGE on indirect pages, assume PAGE_CACHE_SIZE:
+	 * might be reconsidered if it ever diverges from PAGE_SIZE.
+	 */
+	return alloc_pages(gfp_mask, PAGE_CACHE_SHIFT-PAGE_SHIFT);
+}
+
+static inline void shmem_dir_free(struct page *page)
+{
+	__free_pages(page, PAGE_CACHE_SHIFT-PAGE_SHIFT);
+}
+
+static struct page **shmem_dir_map(struct page *page)
+{
+	return (struct page **)kmap_atomic(page, KM_USER0);
+}
+
+static inline void shmem_dir_unmap(struct page **dir)
+{
+	kunmap_atomic(dir, KM_USER0);
+}
+
+static swp_entry_t *shmem_swp_map(struct page *page)
+{
+	return (swp_entry_t *)kmap_atomic(page, KM_USER1);
+}
+
+static inline void shmem_swp_balance_unmap(void)
+{
+	/*
+	 * When passing a pointer to an i_direct entry, to code which
+	 * also handles indirect entries and so will shmem_swp_unmap,
+	 * we must arrange for the preempt count to remain in balance.
+	 * What kmap_atomic of a lowmem page does depends on config
+	 * and architecture, so pretend to kmap_atomic some lowmem page.
+	 */
+	(void) kmap_atomic(ZERO_PAGE(0), KM_USER1);
+}
+
+static inline void shmem_swp_unmap(swp_entry_t *entry)
+{
+	kunmap_atomic(entry, KM_USER1);
+}
+
+static inline struct shmem_sb_info *SHMEM_SB(struct super_block *sb)
+{
+	return sb->s_fs_info;
+}
+
+/*
+ * shmem_file_setup pre-accounts the whole fixed size of a VM object,
+ * for shared memory and for shared anonymous (/dev/zero) mappings
+ * (unless MAP_NORESERVE and sysctl_overcommit_memory <= 1),
+ * consistent with the pre-accounting of private mappings ...
+ */
+static inline int shmem_acct_size(unsigned long flags, loff_t size)
+{
+	return (flags & VM_ACCOUNT)?
+		security_vm_enough_memory(VM_ACCT(size)): 0;
+}
+
+static inline void shmem_unacct_size(unsigned long flags, loff_t size)
+{
+	if (flags & VM_ACCOUNT)
+		vm_unacct_memory(VM_ACCT(size));
+}
+
+/*
+ * ... whereas tmpfs objects are accounted incrementally as
+ * pages are allocated, in order to allow huge sparse files.
+ * shmem_getpage reports shmem_acct_block failure as -ENOSPC not -ENOMEM,
+ * so that a failure on a sparse tmpfs mapping will give SIGBUS not OOM.
+ */
+static inline int shmem_acct_block(unsigned long flags)
+{
+	return (flags & VM_ACCOUNT)?
+		0: security_vm_enough_memory(VM_ACCT(PAGE_CACHE_SIZE));
+}
+
+static inline void shmem_unacct_blocks(unsigned long flags, long pages)
+{
+	if (!(flags & VM_ACCOUNT))
+		vm_unacct_memory(pages * VM_ACCT(PAGE_CACHE_SIZE));
+}
+
+static struct super_operations shmem_ops;
+static struct address_space_operations shmem_aops;
+static struct file_operations shmem_file_operations;
+static struct inode_operations shmem_inode_operations;
+static struct inode_operations shmem_dir_inode_operations;
+static struct inode_operations shmem_special_inode_operations;
+static struct vm_operations_struct shmem_vm_ops;
+
+static struct backing_dev_info shmem_backing_dev_info = {
+	.ra_pages	= 0,	/* No readahead */
+	.capabilities	= BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK,
+	.unplug_io_fn	= default_unplug_io_fn,
+};
+
+static LIST_HEAD(shmem_swaplist);
+static DEFINE_SPINLOCK(shmem_swaplist_lock);
+
+static void shmem_free_blocks(struct inode *inode, long pages)
+{
+	struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
+	if (sbinfo) {
+		spin_lock(&sbinfo->stat_lock);
+		sbinfo->free_blocks += pages;
+		inode->i_blocks -= pages*BLOCKS_PER_PAGE;
+		spin_unlock(&sbinfo->stat_lock);
+	}
+}
+
+/*
+ * shmem_recalc_inode - recalculate the size of an inode
+ *
+ * @inode: inode to recalc
+ *
+ * We have to calculate the free blocks since the mm can drop
+ * undirtied hole pages behind our back.
+ *
+ * But normally   info->alloced == inode->i_mapping->nrpages + info->swapped
+ * So mm freed is info->alloced - (inode->i_mapping->nrpages + info->swapped)
+ *
+ * It has to be called with the spinlock held.
+ */
+static void shmem_recalc_inode(struct inode *inode)
+{
+	struct shmem_inode_info *info = SHMEM_I(inode);
+	long freed;
+
+	freed = info->alloced - info->swapped - inode->i_mapping->nrpages;
+	if (freed > 0) {
+		info->alloced -= freed;
+		shmem_unacct_blocks(info->flags, freed);
+		shmem_free_blocks(inode, freed);
+	}
+}
+
+/*
+ * shmem_swp_entry - find the swap vector position in the info structure
+ *
+ * @info:  info structure for the inode
+ * @index: index of the page to find
+ * @page:  optional page to add to the structure. Has to be preset to
+ *         all zeros
+ *
+ * If there is no space allocated yet it will return NULL when
+ * page is NULL, else it will use the page for the needed block,
+ * setting it to NULL on return to indicate that it has been used.
+ *
+ * The swap vector is organized the following way:
+ *
+ * There are SHMEM_NR_DIRECT entries directly stored in the
+ * shmem_inode_info structure. So small files do not need an addional
+ * allocation.
+ *
+ * For pages with index > SHMEM_NR_DIRECT there is the pointer
+ * i_indirect which points to a page which holds in the first half
+ * doubly indirect blocks, in the second half triple indirect blocks:
+ *
+ * For an artificial ENTRIES_PER_PAGE = 4 this would lead to the
+ * following layout (for SHMEM_NR_DIRECT == 16):
+ *
+ * i_indirect -> dir --> 16-19
+ * 	      |	     +-> 20-23
+ * 	      |
+ * 	      +-->dir2 --> 24-27
+ * 	      |	       +-> 28-31
+ * 	      |	       +-> 32-35
+ * 	      |	       +-> 36-39
+ * 	      |
+ * 	      +-->dir3 --> 40-43
+ * 	       	       +-> 44-47
+ * 	      	       +-> 48-51
+ * 	      	       +-> 52-55
+ */
+static swp_entry_t *shmem_swp_entry(struct shmem_inode_info *info, unsigned long index, struct page **page)
+{
+	unsigned long offset;
+	struct page **dir;
+	struct page *subdir;
+
+	if (index < SHMEM_NR_DIRECT) {
+		shmem_swp_balance_unmap();
+		return info->i_direct+index;
+	}
+	if (!info->i_indirect) {
+		if (page) {
+			info->i_indirect = *page;
+			*page = NULL;
+		}
+		return NULL;			/* need another page */
+	}
+
+	index -= SHMEM_NR_DIRECT;
+	offset = index % ENTRIES_PER_PAGE;
+	index /= ENTRIES_PER_PAGE;
+	dir = shmem_dir_map(info->i_indirect);
+
+	if (index >= ENTRIES_PER_PAGE/2) {
+		index -= ENTRIES_PER_PAGE/2;
+		dir += ENTRIES_PER_PAGE/2 + index/ENTRIES_PER_PAGE;
+		index %= ENTRIES_PER_PAGE;
+		subdir = *dir;
+		if (!subdir) {
+			if (page) {
+				*dir = *page;
+				*page = NULL;
+			}
+			shmem_dir_unmap(dir);
+			return NULL;		/* need another page */
+		}
+		shmem_dir_unmap(dir);
+		dir = shmem_dir_map(subdir);
+	}
+
+	dir += index;
+	subdir = *dir;
+	if (!subdir) {
+		if (!page || !(subdir = *page)) {
+			shmem_dir_unmap(dir);
+			return NULL;		/* need a page */
+		}
+		*dir = subdir;
+		*page = NULL;
+	}
+	shmem_dir_unmap(dir);
+	return shmem_swp_map(subdir) + offset;
+}
+
+static void shmem_swp_set(struct shmem_inode_info *info, swp_entry_t *entry, unsigned long value)
+{
+	long incdec = value? 1: -1;
+
+	entry->val = value;
+	info->swapped += incdec;
+	if ((unsigned long)(entry - info->i_direct) >= SHMEM_NR_DIRECT)
+		kmap_atomic_to_page(entry)->nr_swapped += incdec;
+}
+
+/*
+ * shmem_swp_alloc - get the position of the swap entry for the page.
+ *                   If it does not exist allocate the entry.
+ *
+ * @info:	info structure for the inode
+ * @index:	index of the page to find
+ * @sgp:	check and recheck i_size? skip allocation?
+ */
+static swp_entry_t *shmem_swp_alloc(struct shmem_inode_info *info, unsigned long index, enum sgp_type sgp)
+{
+	struct inode *inode = &info->vfs_inode;
+	struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
+	struct page *page = NULL;
+	swp_entry_t *entry;
+
+	if (sgp != SGP_WRITE &&
+	    ((loff_t) index << PAGE_CACHE_SHIFT) >= i_size_read(inode))
+		return ERR_PTR(-EINVAL);
+
+	while (!(entry = shmem_swp_entry(info, index, &page))) {
+		if (sgp == SGP_READ)
+			return shmem_swp_map(ZERO_PAGE(0));
+		/*
+		 * Test free_blocks against 1 not 0, since we have 1 data
+		 * page (and perhaps indirect index pages) yet to allocate:
+		 * a waste to allocate index if we cannot allocate data.
+		 */
+		if (sbinfo) {
+			spin_lock(&sbinfo->stat_lock);
+			if (sbinfo->free_blocks <= 1) {
+				spin_unlock(&sbinfo->stat_lock);
+				return ERR_PTR(-ENOSPC);
+			}
+			sbinfo->free_blocks--;
+			inode->i_blocks += BLOCKS_PER_PAGE;
+			spin_unlock(&sbinfo->stat_lock);
+		}
+
+		spin_unlock(&info->lock);
+		page = shmem_dir_alloc(mapping_gfp_mask(inode->i_mapping) | __GFP_ZERO);
+		if (page) {
+			page->nr_swapped = 0;
+		}
+		spin_lock(&info->lock);
+
+		if (!page) {
+			shmem_free_blocks(inode, 1);
+			return ERR_PTR(-ENOMEM);
+		}
+		if (sgp != SGP_WRITE &&
+		    ((loff_t) index << PAGE_CACHE_SHIFT) >= i_size_read(inode)) {
+			entry = ERR_PTR(-EINVAL);
+			break;
+		}
+		if (info->next_index <= index)
+			info->next_index = index + 1;
+	}
+	if (page) {
+		/* another task gave its page, or truncated the file */
+		shmem_free_blocks(inode, 1);
+		shmem_dir_free(page);
+	}
+	if (info->next_index <= index && !IS_ERR(entry))
+		info->next_index = index + 1;
+	return entry;
+}
+
+/*
+ * shmem_free_swp - free some swap entries in a directory
+ *
+ * @dir:   pointer to the directory
+ * @edir:  pointer after last entry of the directory
+ */
+static int shmem_free_swp(swp_entry_t *dir, swp_entry_t *edir)
+{
+	swp_entry_t *ptr;
+	int freed = 0;
+
+	for (ptr = dir; ptr < edir; ptr++) {
+		if (ptr->val) {
+			free_swap_and_cache(*ptr);
+			*ptr = (swp_entry_t){0};
+			freed++;
+		}
+	}
+	return freed;
+}
+
+static int shmem_map_and_free_swp(struct page *subdir,
+		int offset, int limit, struct page ***dir)
+{
+	swp_entry_t *ptr;
+	int freed = 0;
+
+	ptr = shmem_swp_map(subdir);
+	for (; offset < limit; offset += LATENCY_LIMIT) {
+		int size = limit - offset;
+		if (size > LATENCY_LIMIT)
+			size = LATENCY_LIMIT;
+		freed += shmem_free_swp(ptr+offset, ptr+offset+size);
+		if (need_resched()) {
+			shmem_swp_unmap(ptr);
+			if (*dir) {
+				shmem_dir_unmap(*dir);
+				*dir = NULL;
+			}
+			cond_resched();
+			ptr = shmem_swp_map(subdir);
+		}
+	}
+	shmem_swp_unmap(ptr);
+	return freed;
+}
+
+static void shmem_free_pages(struct list_head *next)
+{
+	struct page *page;
+	int freed = 0;
+
+	do {
+		page = container_of(next, struct page, lru);
+		next = next->next;
+		shmem_dir_free(page);
+		freed++;
+		if (freed >= LATENCY_LIMIT) {
+			cond_resched();
+			freed = 0;
+		}
+	} while (next);
+}
+
+static void shmem_truncate(struct inode *inode)
+{
+	struct shmem_inode_info *info = SHMEM_I(inode);
+	unsigned long idx;
+	unsigned long size;
+	unsigned long limit;
+	unsigned long stage;
+	unsigned long diroff;
+	struct page **dir;
+	struct page *topdir;
+	struct page *middir;
+	struct page *subdir;
+	swp_entry_t *ptr;
+	LIST_HEAD(pages_to_free);
+	long nr_pages_to_free = 0;
+	long nr_swaps_freed = 0;
+	int offset;
+	int freed;
+
+	inode->i_ctime = inode->i_mtime = CURRENT_TIME;
+	idx = (inode->i_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
+	if (idx >= info->next_index)
+		return;
+
+	spin_lock(&info->lock);
+	info->flags |= SHMEM_TRUNCATE;
+	limit = info->next_index;
+	info->next_index = idx;
+	topdir = info->i_indirect;
+	if (topdir && idx <= SHMEM_NR_DIRECT) {
+		info->i_indirect = NULL;
+		nr_pages_to_free++;
+		list_add(&topdir->lru, &pages_to_free);
+	}
+	spin_unlock(&info->lock);
+
+	if (info->swapped && idx < SHMEM_NR_DIRECT) {
+		ptr = info->i_direct;
+		size = limit;
+		if (size > SHMEM_NR_DIRECT)
+			size = SHMEM_NR_DIRECT;
+		nr_swaps_freed = shmem_free_swp(ptr+idx, ptr+size);
+	}
+	if (!topdir)
+		goto done2;
+
+	BUG_ON(limit <= SHMEM_NR_DIRECT);
+	limit -= SHMEM_NR_DIRECT;
+	idx = (idx > SHMEM_NR_DIRECT)? (idx - SHMEM_NR_DIRECT): 0;
+	offset = idx % ENTRIES_PER_PAGE;
+	idx -= offset;
+
+	dir = shmem_dir_map(topdir);
+	stage = ENTRIES_PER_PAGEPAGE/2;
+	if (idx < ENTRIES_PER_PAGEPAGE/2) {
+		middir = topdir;
+		diroff = idx/ENTRIES_PER_PAGE;
+	} else {
+		dir += ENTRIES_PER_PAGE/2;
+		dir += (idx - ENTRIES_PER_PAGEPAGE/2)/ENTRIES_PER_PAGEPAGE;
+		while (stage <= idx)
+			stage += ENTRIES_PER_PAGEPAGE;
+		middir = *dir;
+		if (*dir) {
+			diroff = ((idx - ENTRIES_PER_PAGEPAGE/2) %
+				ENTRIES_PER_PAGEPAGE) / ENTRIES_PER_PAGE;
+			if (!diroff && !offset) {
+				*dir = NULL;
+				nr_pages_to_free++;
+				list_add(&middir->lru, &pages_to_free);
+			}
+			shmem_dir_unmap(dir);
+			dir = shmem_dir_map(middir);
+		} else {
+			diroff = 0;
+			offset = 0;
+			idx = stage;
+		}
+	}
+
+	for (; idx < limit; idx += ENTRIES_PER_PAGE, diroff++) {
+		if (unlikely(idx == stage)) {
+			shmem_dir_unmap(dir);
+			dir = shmem_dir_map(topdir) +
+			    ENTRIES_PER_PAGE/2 + idx/ENTRIES_PER_PAGEPAGE;
+			while (!*dir) {
+				dir++;
+				idx += ENTRIES_PER_PAGEPAGE;
+				if (idx >= limit)
+					goto done1;
+			}
+			stage = idx + ENTRIES_PER_PAGEPAGE;
+			middir = *dir;
+			*dir = NULL;
+			nr_pages_to_free++;
+			list_add(&middir->lru, &pages_to_free);
+			shmem_dir_unmap(dir);
+			cond_resched();
+			dir = shmem_dir_map(middir);
+			diroff = 0;
+		}
+		subdir = dir[diroff];
+		if (subdir && subdir->nr_swapped) {
+			size = limit - idx;
+			if (size > ENTRIES_PER_PAGE)
+				size = ENTRIES_PER_PAGE;
+			freed = shmem_map_and_free_swp(subdir,
+						offset, size, &dir);
+			if (!dir)
+				dir = shmem_dir_map(middir);
+			nr_swaps_freed += freed;
+			if (offset)
+				spin_lock(&info->lock);
+			subdir->nr_swapped -= freed;
+			if (offset)
+				spin_unlock(&info->lock);
+			BUG_ON(subdir->nr_swapped > offset);
+		}
+		if (offset)
+			offset = 0;
+		else if (subdir) {
+			dir[diroff] = NULL;
+			nr_pages_to_free++;
+			list_add(&subdir->lru, &pages_to_free);
+		}
+	}
+done1:
+	shmem_dir_unmap(dir);
+done2:
+	if (inode->i_mapping->nrpages && (info->flags & SHMEM_PAGEIN)) {
+		/*
+		 * Call truncate_inode_pages again: racing shmem_unuse_inode
+		 * may have swizzled a page in from swap since vmtruncate or
+		 * generic_delete_inode did it, before we lowered next_index.
+		 * Also, though shmem_getpage checks i_size before adding to
+		 * cache, no recheck after: so fix the narrow window there too.
+		 */
+		truncate_inode_pages(inode->i_mapping, inode->i_size);
+	}
+
+	spin_lock(&info->lock);
+	info->flags &= ~SHMEM_TRUNCATE;
+	info->swapped -= nr_swaps_freed;
+	if (nr_pages_to_free)
+		shmem_free_blocks(inode, nr_pages_to_free);
+	shmem_recalc_inode(inode);
+	spin_unlock(&info->lock);
+
+	/*
+	 * Empty swap vector directory pages to be freed?
+	 */
+	if (!list_empty(&pages_to_free)) {
+		pages_to_free.prev->next = NULL;
+		shmem_free_pages(pages_to_free.next);
+	}
+}
+
+static int shmem_notify_change(struct dentry *dentry, struct iattr *attr)
+{
+	struct inode *inode = dentry->d_inode;
+	struct page *page = NULL;
+	int error;
+
+	if (attr->ia_valid & ATTR_SIZE) {
+		if (attr->ia_size < inode->i_size) {
+			/*
+			 * If truncating down to a partial page, then
+			 * if that page is already allocated, hold it
+			 * in memory until the truncation is over, so
+			 * truncate_partial_page cannnot miss it were
+			 * it assigned to swap.
+			 */
+			if (attr->ia_size & (PAGE_CACHE_SIZE-1)) {
+				(void) shmem_getpage(inode,
+					attr->ia_size>>PAGE_CACHE_SHIFT,
+						&page, SGP_READ, NULL);
+			}
+			/*
+			 * Reset SHMEM_PAGEIN flag so that shmem_truncate can
+			 * detect if any pages might have been added to cache
+			 * after truncate_inode_pages.  But we needn't bother
+			 * if it's being fully truncated to zero-length: the
+			 * nrpages check is efficient enough in that case.
+			 */
+			if (attr->ia_size) {
+				struct shmem_inode_info *info = SHMEM_I(inode);
+				spin_lock(&info->lock);
+				info->flags &= ~SHMEM_PAGEIN;
+				spin_unlock(&info->lock);
+			}
+		}
+	}
+
+	error = inode_change_ok(inode, attr);
+	if (!error)
+		error = inode_setattr(inode, attr);
+	if (page)
+		page_cache_release(page);
+	return error;
+}
+
+static void shmem_delete_inode(struct inode *inode)
+{
+	struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
+	struct shmem_inode_info *info = SHMEM_I(inode);
+
+	if (inode->i_op->truncate == shmem_truncate) {
+		shmem_unacct_size(info->flags, inode->i_size);
+		inode->i_size = 0;
+		shmem_truncate(inode);
+		if (!list_empty(&info->swaplist)) {
+			spin_lock(&shmem_swaplist_lock);
+			list_del_init(&info->swaplist);
+			spin_unlock(&shmem_swaplist_lock);
+		}
+	}
+	if (sbinfo) {
+		BUG_ON(inode->i_blocks);
+		spin_lock(&sbinfo->stat_lock);
+		sbinfo->free_inodes++;
+		spin_unlock(&sbinfo->stat_lock);
+	}
+	clear_inode(inode);
+}
+
+static inline int shmem_find_swp(swp_entry_t entry, swp_entry_t *dir, swp_entry_t *edir)
+{
+	swp_entry_t *ptr;
+
+	for (ptr = dir; ptr < edir; ptr++) {
+		if (ptr->val == entry.val)
+			return ptr - dir;
+	}
+	return -1;
+}
+
+static int shmem_unuse_inode(struct shmem_inode_info *info, swp_entry_t entry, struct page *page)
+{
+	struct inode *inode;
+	unsigned long idx;
+	unsigned long size;
+	unsigned long limit;
+	unsigned long stage;
+	struct page **dir;
+	struct page *subdir;
+	swp_entry_t *ptr;
+	int offset;
+
+	idx = 0;
+	ptr = info->i_direct;
+	spin_lock(&info->lock);
+	limit = info->next_index;
+	size = limit;
+	if (size > SHMEM_NR_DIRECT)
+		size = SHMEM_NR_DIRECT;
+	offset = shmem_find_swp(entry, ptr, ptr+size);
+	if (offset >= 0) {
+		shmem_swp_balance_unmap();
+		goto found;
+	}
+	if (!info->i_indirect)
+		goto lost2;
+
+	dir = shmem_dir_map(info->i_indirect);
+	stage = SHMEM_NR_DIRECT + ENTRIES_PER_PAGEPAGE/2;
+
+	for (idx = SHMEM_NR_DIRECT; idx < limit; idx += ENTRIES_PER_PAGE, dir++) {
+		if (unlikely(idx == stage)) {
+			shmem_dir_unmap(dir-1);
+			dir = shmem_dir_map(info->i_indirect) +
+			    ENTRIES_PER_PAGE/2 + idx/ENTRIES_PER_PAGEPAGE;
+			while (!*dir) {
+				dir++;
+				idx += ENTRIES_PER_PAGEPAGE;
+				if (idx >= limit)
+					goto lost1;
+			}
+			stage = idx + ENTRIES_PER_PAGEPAGE;
+			subdir = *dir;
+			shmem_dir_unmap(dir);
+			dir = shmem_dir_map(subdir);
+		}
+		subdir = *dir;
+		if (subdir && subdir->nr_swapped) {
+			ptr = shmem_swp_map(subdir);
+			size = limit - idx;
+			if (size > ENTRIES_PER_PAGE)
+				size = ENTRIES_PER_PAGE;
+			offset = shmem_find_swp(entry, ptr, ptr+size);
+			if (offset >= 0) {
+				shmem_dir_unmap(dir);
+				goto found;
+			}
+			shmem_swp_unmap(ptr);
+		}
+	}
+lost1:
+	shmem_dir_unmap(dir-1);
+lost2:
+	spin_unlock(&info->lock);
+	return 0;
+found:
+	idx += offset;
+	inode = &info->vfs_inode;
+	if (move_from_swap_cache(page, idx, inode->i_mapping) == 0) {
+		info->flags |= SHMEM_PAGEIN;
+		shmem_swp_set(info, ptr + offset, 0);
+	}
+	shmem_swp_unmap(ptr);
+	spin_unlock(&info->lock);
+	/*
+	 * Decrement swap count even when the entry is left behind:
+	 * try_to_unuse will skip over mms, then reincrement count.
+	 */
+	swap_free(entry);
+	return 1;
+}
+
+/*
+ * shmem_unuse() search for an eventually swapped out shmem page.
+ */
+int shmem_unuse(swp_entry_t entry, struct page *page)
+{
+	struct list_head *p, *next;
+	struct shmem_inode_info *info;
+	int found = 0;
+
+	spin_lock(&shmem_swaplist_lock);
+	list_for_each_safe(p, next, &shmem_swaplist) {
+		info = list_entry(p, struct shmem_inode_info, swaplist);
+		if (!info->swapped)
+			list_del_init(&info->swaplist);
+		else if (shmem_unuse_inode(info, entry, page)) {
+			/* move head to start search for next from here */
+			list_move_tail(&shmem_swaplist, &info->swaplist);
+			found = 1;
+			break;
+		}
+	}
+	spin_unlock(&shmem_swaplist_lock);
+	return found;
+}
+
+/*
+ * Move the page from the page cache to the swap cache.
+ */
+static int shmem_writepage(struct page *page, struct writeback_control *wbc)
+{
+	struct shmem_inode_info *info;
+	swp_entry_t *entry, swap;
+	struct address_space *mapping;
+	unsigned long index;
+	struct inode *inode;
+
+	BUG_ON(!PageLocked(page));
+	BUG_ON(page_mapped(page));
+
+	mapping = page->mapping;
+	index = page->index;
+	inode = mapping->host;
+	info = SHMEM_I(inode);
+	if (info->flags & VM_LOCKED)
+		goto redirty;
+	swap = get_swap_page();
+	if (!swap.val)
+		goto redirty;
+
+	spin_lock(&info->lock);
+	shmem_recalc_inode(inode);
+	if (index >= info->next_index) {
+		BUG_ON(!(info->flags & SHMEM_TRUNCATE));
+		goto unlock;
+	}
+	entry = shmem_swp_entry(info, index, NULL);
+	BUG_ON(!entry);
+	BUG_ON(entry->val);
+
+	if (move_to_swap_cache(page, swap) == 0) {
+		shmem_swp_set(info, entry, swap.val);
+		shmem_swp_unmap(entry);
+		spin_unlock(&info->lock);
+		if (list_empty(&info->swaplist)) {
+			spin_lock(&shmem_swaplist_lock);
+			/* move instead of add in case we're racing */
+			list_move_tail(&info->swaplist, &shmem_swaplist);
+			spin_unlock(&shmem_swaplist_lock);
+		}
+		unlock_page(page);
+		return 0;
+	}
+
+	shmem_swp_unmap(entry);
+unlock:
+	spin_unlock(&info->lock);
+	swap_free(swap);
+redirty:
+	set_page_dirty(page);
+	return WRITEPAGE_ACTIVATE;	/* Return with the page locked */
+}
+
+#ifdef CONFIG_NUMA
+static struct page *shmem_swapin_async(struct shared_policy *p,
+				       swp_entry_t entry, unsigned long idx)
+{
+	struct page *page;
+	struct vm_area_struct pvma;
+
+	/* Create a pseudo vma that just contains the policy */
+	memset(&pvma, 0, sizeof(struct vm_area_struct));
+	pvma.vm_end = PAGE_SIZE;
+	pvma.vm_pgoff = idx;
+	pvma.vm_policy = mpol_shared_policy_lookup(p, idx);
+	page = read_swap_cache_async(entry, &pvma, 0);
+	mpol_free(pvma.vm_policy);
+	return page;
+}
+
+struct page *shmem_swapin(struct shmem_inode_info *info, swp_entry_t entry,
+			  unsigned long idx)
+{
+	struct shared_policy *p = &info->policy;
+	int i, num;
+	struct page *page;
+	unsigned long offset;
+
+	num = valid_swaphandles(entry, &offset);
+	for (i = 0; i < num; offset++, i++) {
+		page = shmem_swapin_async(p,
+				swp_entry(swp_type(entry), offset), idx);
+		if (!page)
+			break;
+		page_cache_release(page);
+	}
+	lru_add_drain();	/* Push any new pages onto the LRU now */
+	return shmem_swapin_async(p, entry, idx);
+}
+
+static struct page *
+shmem_alloc_page(unsigned long gfp, struct shmem_inode_info *info,
+		 unsigned long idx)
+{
+	struct vm_area_struct pvma;
+	struct page *page;
+
+	memset(&pvma, 0, sizeof(struct vm_area_struct));
+	pvma.vm_policy = mpol_shared_policy_lookup(&info->policy, idx);
+	pvma.vm_pgoff = idx;
+	pvma.vm_end = PAGE_SIZE;
+	page = alloc_page_vma(gfp | __GFP_ZERO, &pvma, 0);
+	mpol_free(pvma.vm_policy);
+	return page;
+}
+#else
+static inline struct page *
+shmem_swapin(struct shmem_inode_info *info,swp_entry_t entry,unsigned long idx)
+{
+	swapin_readahead(entry, 0, NULL);
+	return read_swap_cache_async(entry, NULL, 0);
+}
+
+static inline struct page *
+shmem_alloc_page(unsigned int __nocast gfp,struct shmem_inode_info *info,
+				 unsigned long idx)
+{
+	return alloc_page(gfp | __GFP_ZERO);
+}
+#endif
+
+/*
+ * shmem_getpage - either get the page from swap or allocate a new one
+ *
+ * If we allocate a new one we do not mark it dirty. That's up to the
+ * vm. If we swap it in we mark it dirty since we also free the swap
+ * entry since a page cannot live in both the swap and page cache
+ */
+static int shmem_getpage(struct inode *inode, unsigned long idx,
+			struct page **pagep, enum sgp_type sgp, int *type)
+{
+	struct address_space *mapping = inode->i_mapping;
+	struct shmem_inode_info *info = SHMEM_I(inode);
+	struct shmem_sb_info *sbinfo;
+	struct page *filepage = *pagep;
+	struct page *swappage;
+	swp_entry_t *entry;
+	swp_entry_t swap;
+	int error;
+
+	if (idx >= SHMEM_MAX_INDEX)
+		return -EFBIG;
+	/*
+	 * Normally, filepage is NULL on entry, and either found
+	 * uptodate immediately, or allocated and zeroed, or read
+	 * in under swappage, which is then assigned to filepage.
+	 * But shmem_prepare_write passes in a locked filepage,
+	 * which may be found not uptodate by other callers too,
+	 * and may need to be copied from the swappage read in.
+	 */
+repeat:
+	if (!filepage)
+		filepage = find_lock_page(mapping, idx);
+	if (filepage && PageUptodate(filepage))
+		goto done;
+	error = 0;
+	if (sgp == SGP_QUICK)
+		goto failed;
+
+	spin_lock(&info->lock);
+	shmem_recalc_inode(inode);
+	entry = shmem_swp_alloc(info, idx, sgp);
+	if (IS_ERR(entry)) {
+		spin_unlock(&info->lock);
+		error = PTR_ERR(entry);
+		goto failed;
+	}
+	swap = *entry;
+
+	if (swap.val) {
+		/* Look it up and read it in.. */
+		swappage = lookup_swap_cache(swap);
+		if (!swappage) {
+			shmem_swp_unmap(entry);
+			spin_unlock(&info->lock);
+			/* here we actually do the io */
+			if (type && *type == VM_FAULT_MINOR) {
+				inc_page_state(pgmajfault);
+				*type = VM_FAULT_MAJOR;
+			}
+			swappage = shmem_swapin(info, swap, idx);
+			if (!swappage) {
+				spin_lock(&info->lock);
+				entry = shmem_swp_alloc(info, idx, sgp);
+				if (IS_ERR(entry))
+					error = PTR_ERR(entry);
+				else {
+					if (entry->val == swap.val)
+						error = -ENOMEM;
+					shmem_swp_unmap(entry);
+				}
+				spin_unlock(&info->lock);
+				if (error)
+					goto failed;
+				goto repeat;
+			}
+			wait_on_page_locked(swappage);
+			page_cache_release(swappage);
+			goto repeat;
+		}
+
+		/* We have to do this with page locked to prevent races */
+		if (TestSetPageLocked(swappage)) {
+			shmem_swp_unmap(entry);
+			spin_unlock(&info->lock);
+			wait_on_page_locked(swappage);
+			page_cache_release(swappage);
+			goto repeat;
+		}
+		if (PageWriteback(swappage)) {
+			shmem_swp_unmap(entry);
+			spin_unlock(&info->lock);
+			wait_on_page_writeback(swappage);
+			unlock_page(swappage);
+			page_cache_release(swappage);
+			goto repeat;
+		}
+		if (!PageUptodate(swappage)) {
+			shmem_swp_unmap(entry);
+			spin_unlock(&info->lock);
+			unlock_page(swappage);
+			page_cache_release(swappage);
+			error = -EIO;
+			goto failed;
+		}
+
+		if (filepage) {
+			shmem_swp_set(info, entry, 0);
+			shmem_swp_unmap(entry);
+			delete_from_swap_cache(swappage);
+			spin_unlock(&info->lock);
+			copy_highpage(filepage, swappage);
+			unlock_page(swappage);
+			page_cache_release(swappage);
+			flush_dcache_page(filepage);
+			SetPageUptodate(filepage);
+			set_page_dirty(filepage);
+			swap_free(swap);
+		} else if (!(error = move_from_swap_cache(
+				swappage, idx, mapping))) {
+			info->flags |= SHMEM_PAGEIN;
+			shmem_swp_set(info, entry, 0);
+			shmem_swp_unmap(entry);
+			spin_unlock(&info->lock);
+			filepage = swappage;
+			swap_free(swap);
+		} else {
+			shmem_swp_unmap(entry);
+			spin_unlock(&info->lock);
+			unlock_page(swappage);
+			page_cache_release(swappage);
+			if (error == -ENOMEM) {
+				/* let kswapd refresh zone for GFP_ATOMICs */
+				blk_congestion_wait(WRITE, HZ/50);
+			}
+			goto repeat;
+		}
+	} else if (sgp == SGP_READ && !filepage) {
+		shmem_swp_unmap(entry);
+		filepage = find_get_page(mapping, idx);
+		if (filepage &&
+		    (!PageUptodate(filepage) || TestSetPageLocked(filepage))) {
+			spin_unlock(&info->lock);
+			wait_on_page_locked(filepage);
+			page_cache_release(filepage);
+			filepage = NULL;
+			goto repeat;
+		}
+		spin_unlock(&info->lock);
+	} else {
+		shmem_swp_unmap(entry);
+		sbinfo = SHMEM_SB(inode->i_sb);
+		if (sbinfo) {
+			spin_lock(&sbinfo->stat_lock);
+			if (sbinfo->free_blocks == 0 ||
+			    shmem_acct_block(info->flags)) {
+				spin_unlock(&sbinfo->stat_lock);
+				spin_unlock(&info->lock);
+				error = -ENOSPC;
+				goto failed;
+			}
+			sbinfo->free_blocks--;
+			inode->i_blocks += BLOCKS_PER_PAGE;
+			spin_unlock(&sbinfo->stat_lock);
+		} else if (shmem_acct_block(info->flags)) {
+			spin_unlock(&info->lock);
+			error = -ENOSPC;
+			goto failed;
+		}
+
+		if (!filepage) {
+			spin_unlock(&info->lock);
+			filepage = shmem_alloc_page(mapping_gfp_mask(mapping),
+						    info,
+						    idx);
+			if (!filepage) {
+				shmem_unacct_blocks(info->flags, 1);
+				shmem_free_blocks(inode, 1);
+				error = -ENOMEM;
+				goto failed;
+			}
+
+			spin_lock(&info->lock);
+			entry = shmem_swp_alloc(info, idx, sgp);
+			if (IS_ERR(entry))
+				error = PTR_ERR(entry);
+			else {
+				swap = *entry;
+				shmem_swp_unmap(entry);
+			}
+			if (error || swap.val || 0 != add_to_page_cache_lru(
+					filepage, mapping, idx, GFP_ATOMIC)) {
+				spin_unlock(&info->lock);
+				page_cache_release(filepage);
+				shmem_unacct_blocks(info->flags, 1);
+				shmem_free_blocks(inode, 1);
+				filepage = NULL;
+				if (error)
+					goto failed;
+				goto repeat;
+			}
+			info->flags |= SHMEM_PAGEIN;
+		}
+
+		info->alloced++;
+		spin_unlock(&info->lock);
+		flush_dcache_page(filepage);
+		SetPageUptodate(filepage);
+	}
+done:
+	if (*pagep != filepage) {
+		unlock_page(filepage);
+		*pagep = filepage;
+	}
+	return 0;
+
+failed:
+	if (*pagep != filepage) {
+		unlock_page(filepage);
+		page_cache_release(filepage);
+	}
+	return error;
+}
+
+struct page *shmem_nopage(struct vm_area_struct *vma, unsigned long address, int *type)
+{
+	struct inode *inode = vma->vm_file->f_dentry->d_inode;
+	struct page *page = NULL;
+	unsigned long idx;
+	int error;
+
+	idx = (address - vma->vm_start) >> PAGE_SHIFT;
+	idx += vma->vm_pgoff;
+	idx >>= PAGE_CACHE_SHIFT - PAGE_SHIFT;
+	if (((loff_t) idx << PAGE_CACHE_SHIFT) >= i_size_read(inode))
+		return NOPAGE_SIGBUS;
+
+	error = shmem_getpage(inode, idx, &page, SGP_CACHE, type);
+	if (error)
+		return (error == -ENOMEM)? NOPAGE_OOM: NOPAGE_SIGBUS;
+
+	mark_page_accessed(page);
+	return page;
+}
+
+static int shmem_populate(struct vm_area_struct *vma,
+	unsigned long addr, unsigned long len,
+	pgprot_t prot, unsigned long pgoff, int nonblock)
+{
+	struct inode *inode = vma->vm_file->f_dentry->d_inode;
+	struct mm_struct *mm = vma->vm_mm;
+	enum sgp_type sgp = nonblock? SGP_QUICK: SGP_CACHE;
+	unsigned long size;
+
+	size = (i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT;
+	if (pgoff >= size || pgoff + (len >> PAGE_SHIFT) > size)
+		return -EINVAL;
+
+	while ((long) len > 0) {
+		struct page *page = NULL;
+		int err;
+		/*
+		 * Will need changing if PAGE_CACHE_SIZE != PAGE_SIZE
+		 */
+		err = shmem_getpage(inode, pgoff, &page, sgp, NULL);
+		if (err)
+			return err;
+		if (page) {
+			mark_page_accessed(page);
+			err = install_page(mm, vma, addr, page, prot);
+			if (err) {
+				page_cache_release(page);
+				return err;
+			}
+		} else if (nonblock) {
+    			err = install_file_pte(mm, vma, addr, pgoff, prot);
+			if (err)
+	    			return err;
+		}
+
+		len -= PAGE_SIZE;
+		addr += PAGE_SIZE;
+		pgoff++;
+	}
+	return 0;
+}
+
+#ifdef CONFIG_NUMA
+int shmem_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
+{
+	struct inode *i = vma->vm_file->f_dentry->d_inode;
+	return mpol_set_shared_policy(&SHMEM_I(i)->policy, vma, new);
+}
+
+struct mempolicy *
+shmem_get_policy(struct vm_area_struct *vma, unsigned long addr)
+{
+	struct inode *i = vma->vm_file->f_dentry->d_inode;
+	unsigned long idx;
+
+	idx = ((addr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
+	return mpol_shared_policy_lookup(&SHMEM_I(i)->policy, idx);
+}
+#endif
+
+int shmem_lock(struct file *file, int lock, struct user_struct *user)
+{
+	struct inode *inode = file->f_dentry->d_inode;
+	struct shmem_inode_info *info = SHMEM_I(inode);
+	int retval = -ENOMEM;
+
+	spin_lock(&info->lock);
+	if (lock && !(info->flags & VM_LOCKED)) {
+		if (!user_shm_lock(inode->i_size, user))
+			goto out_nomem;
+		info->flags |= VM_LOCKED;
+	}
+	if (!lock && (info->flags & VM_LOCKED) && user) {
+		user_shm_unlock(inode->i_size, user);
+		info->flags &= ~VM_LOCKED;
+	}
+	retval = 0;
+out_nomem:
+	spin_unlock(&info->lock);
+	return retval;
+}
+
+static int shmem_mmap(struct file *file, struct vm_area_struct *vma)
+{
+	file_accessed(file);
+	vma->vm_ops = &shmem_vm_ops;
+	return 0;
+}
+
+static struct inode *
+shmem_get_inode(struct super_block *sb, int mode, dev_t dev)
+{
+	struct inode *inode;
+	struct shmem_inode_info *info;
+	struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
+
+	if (sbinfo) {
+		spin_lock(&sbinfo->stat_lock);
+		if (!sbinfo->free_inodes) {
+			spin_unlock(&sbinfo->stat_lock);
+			return NULL;
+		}
+		sbinfo->free_inodes--;
+		spin_unlock(&sbinfo->stat_lock);
+	}
+
+	inode = new_inode(sb);
+	if (inode) {
+		inode->i_mode = mode;
+		inode->i_uid = current->fsuid;
+		inode->i_gid = current->fsgid;
+		inode->i_blksize = PAGE_CACHE_SIZE;
+		inode->i_blocks = 0;
+		inode->i_mapping->a_ops = &shmem_aops;
+		inode->i_mapping->backing_dev_info = &shmem_backing_dev_info;
+		inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
+		info = SHMEM_I(inode);
+		memset(info, 0, (char *)inode - (char *)info);
+		spin_lock_init(&info->lock);
+		INIT_LIST_HEAD(&info->swaplist);
+
+		switch (mode & S_IFMT) {
+		default:
+			inode->i_op = &shmem_special_inode_operations;
+			init_special_inode(inode, mode, dev);
+			break;
+		case S_IFREG:
+			inode->i_op = &shmem_inode_operations;
+			inode->i_fop = &shmem_file_operations;
+			mpol_shared_policy_init(&info->policy);
+			break;
+		case S_IFDIR:
+			inode->i_nlink++;
+			/* Some things misbehave if size == 0 on a directory */
+			inode->i_size = 2 * BOGO_DIRENT_SIZE;
+			inode->i_op = &shmem_dir_inode_operations;
+			inode->i_fop = &simple_dir_operations;
+			break;
+		case S_IFLNK:
+			/*
+			 * Must not load anything in the rbtree,
+			 * mpol_free_shared_policy will not be called.
+			 */
+			mpol_shared_policy_init(&info->policy);
+			break;
+		}
+	} else if (sbinfo) {
+		spin_lock(&sbinfo->stat_lock);
+		sbinfo->free_inodes++;
+		spin_unlock(&sbinfo->stat_lock);
+	}
+	return inode;
+}
+
+#ifdef CONFIG_TMPFS
+
+static int shmem_set_size(struct shmem_sb_info *sbinfo,
+			  unsigned long max_blocks, unsigned long max_inodes)
+{
+	int error;
+	unsigned long blocks, inodes;
+
+	spin_lock(&sbinfo->stat_lock);
+	blocks = sbinfo->max_blocks - sbinfo->free_blocks;
+	inodes = sbinfo->max_inodes - sbinfo->free_inodes;
+	error = -EINVAL;
+	if (max_blocks < blocks)
+		goto out;
+	if (max_inodes < inodes)
+		goto out;
+	error = 0;
+	sbinfo->max_blocks  = max_blocks;
+	sbinfo->free_blocks = max_blocks - blocks;
+	sbinfo->max_inodes  = max_inodes;
+	sbinfo->free_inodes = max_inodes - inodes;
+out:
+	spin_unlock(&sbinfo->stat_lock);
+	return error;
+}
+
+static struct inode_operations shmem_symlink_inode_operations;
+static struct inode_operations shmem_symlink_inline_operations;
+
+/*
+ * Normally tmpfs makes no use of shmem_prepare_write, but it
+ * lets a tmpfs file be used read-write below the loop driver.
+ */
+static int
+shmem_prepare_write(struct file *file, struct page *page, unsigned offset, unsigned to)
+{
+	struct inode *inode = page->mapping->host;
+	return shmem_getpage(inode, page->index, &page, SGP_WRITE, NULL);
+}
+
+static ssize_t
+shmem_file_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
+{
+	struct inode	*inode = file->f_dentry->d_inode;
+	loff_t		pos;
+	unsigned long	written;
+	ssize_t		err;
+
+	if ((ssize_t) count < 0)
+		return -EINVAL;
+
+	if (!access_ok(VERIFY_READ, buf, count))
+		return -EFAULT;
+
+	down(&inode->i_sem);
+
+	pos = *ppos;
+	written = 0;
+
+	err = generic_write_checks(file, &pos, &count, 0);
+	if (err || !count)
+		goto out;
+
+	err = remove_suid(file->f_dentry);
+	if (err)
+		goto out;
+
+	inode->i_ctime = inode->i_mtime = CURRENT_TIME;
+
+	do {
+		struct page *page = NULL;
+		unsigned long bytes, index, offset;
+		char *kaddr;
+		int left;
+
+		offset = (pos & (PAGE_CACHE_SIZE -1)); /* Within page */
+		index = pos >> PAGE_CACHE_SHIFT;
+		bytes = PAGE_CACHE_SIZE - offset;
+		if (bytes > count)
+			bytes = count;
+
+		/*
+		 * We don't hold page lock across copy from user -
+		 * what would it guard against? - so no deadlock here.
+		 * But it still may be a good idea to prefault below.
+		 */
+
+		err = shmem_getpage(inode, index, &page, SGP_WRITE, NULL);
+		if (err)
+			break;
+
+		left = bytes;
+		if (PageHighMem(page)) {
+			volatile unsigned char dummy;
+			__get_user(dummy, buf);
+			__get_user(dummy, buf + bytes - 1);
+
+			kaddr = kmap_atomic(page, KM_USER0);
+			left = __copy_from_user_inatomic(kaddr + offset,
+							buf, bytes);
+			kunmap_atomic(kaddr, KM_USER0);
+		}
+		if (left) {
+			kaddr = kmap(page);
+			left = __copy_from_user(kaddr + offset, buf, bytes);
+			kunmap(page);
+		}
+
+		written += bytes;
+		count -= bytes;
+		pos += bytes;
+		buf += bytes;
+		if (pos > inode->i_size)
+			i_size_write(inode, pos);
+
+		flush_dcache_page(page);
+		set_page_dirty(page);
+		mark_page_accessed(page);
+		page_cache_release(page);
+
+		if (left) {
+			pos -= left;
+			written -= left;
+			err = -EFAULT;
+			break;
+		}
+
+		/*
+		 * Our dirty pages are not counted in nr_dirty,
+		 * and we do not attempt to balance dirty pages.
+		 */
+
+		cond_resched();
+	} while (count);
+
+	*ppos = pos;
+	if (written)
+		err = written;
+out:
+	up(&inode->i_sem);
+	return err;
+}
+
+static void do_shmem_file_read(struct file *filp, loff_t *ppos, read_descriptor_t *desc, read_actor_t actor)
+{
+	struct inode *inode = filp->f_dentry->d_inode;
+	struct address_space *mapping = inode->i_mapping;
+	unsigned long index, offset;
+
+	index = *ppos >> PAGE_CACHE_SHIFT;
+	offset = *ppos & ~PAGE_CACHE_MASK;
+
+	for (;;) {
+		struct page *page = NULL;
+		unsigned long end_index, nr, ret;
+		loff_t i_size = i_size_read(inode);
+
+		end_index = i_size >> PAGE_CACHE_SHIFT;
+		if (index > end_index)
+			break;
+		if (index == end_index) {
+			nr = i_size & ~PAGE_CACHE_MASK;
+			if (nr <= offset)
+				break;
+		}
+
+		desc->error = shmem_getpage(inode, index, &page, SGP_READ, NULL);
+		if (desc->error) {
+			if (desc->error == -EINVAL)
+				desc->error = 0;
+			break;
+		}
+
+		/*
+		 * We must evaluate after, since reads (unlike writes)
+		 * are called without i_sem protection against truncate
+		 */
+		nr = PAGE_CACHE_SIZE;
+		i_size = i_size_read(inode);
+		end_index = i_size >> PAGE_CACHE_SHIFT;
+		if (index == end_index) {
+			nr = i_size & ~PAGE_CACHE_MASK;
+			if (nr <= offset) {
+				if (page)
+					page_cache_release(page);
+				break;
+			}
+		}
+		nr -= offset;
+
+		if (page) {
+			/*
+			 * If users can be writing to this page using arbitrary
+			 * virtual addresses, take care about potential aliasing
+			 * before reading the page on the kernel side.
+			 */
+			if (mapping_writably_mapped(mapping))
+				flush_dcache_page(page);
+			/*
+			 * Mark the page accessed if we read the beginning.
+			 */
+			if (!offset)
+				mark_page_accessed(page);
+		} else
+			page = ZERO_PAGE(0);
+
+		/*
+		 * Ok, we have the page, and it's up-to-date, so
+		 * now we can copy it to user space...
+		 *
+		 * The actor routine returns how many bytes were actually used..
+		 * NOTE! This may not be the same as how much of a user buffer
+		 * we filled up (we may be padding etc), so we can only update
+		 * "pos" here (the actor routine has to update the user buffer
+		 * pointers and the remaining count).
+		 */
+		ret = actor(desc, page, offset, nr);
+		offset += ret;
+		index += offset >> PAGE_CACHE_SHIFT;
+		offset &= ~PAGE_CACHE_MASK;
+
+		page_cache_release(page);
+		if (ret != nr || !desc->count)
+			break;
+
+		cond_resched();
+	}
+
+	*ppos = ((loff_t) index << PAGE_CACHE_SHIFT) + offset;
+	file_accessed(filp);
+}
+
+static ssize_t shmem_file_read(struct file *filp, char __user *buf, size_t count, loff_t *ppos)
+{
+	read_descriptor_t desc;
+
+	if ((ssize_t) count < 0)
+		return -EINVAL;
+	if (!access_ok(VERIFY_WRITE, buf, count))
+		return -EFAULT;
+	if (!count)
+		return 0;
+
+	desc.written = 0;
+	desc.count = count;
+	desc.arg.buf = buf;
+	desc.error = 0;
+
+	do_shmem_file_read(filp, ppos, &desc, file_read_actor);
+	if (desc.written)
+		return desc.written;
+	return desc.error;
+}
+
+static ssize_t shmem_file_sendfile(struct file *in_file, loff_t *ppos,
+			 size_t count, read_actor_t actor, void *target)
+{
+	read_descriptor_t desc;
+
+	if (!count)
+		return 0;
+
+	desc.written = 0;
+	desc.count = count;
+	desc.arg.data = target;
+	desc.error = 0;
+
+	do_shmem_file_read(in_file, ppos, &desc, actor);
+	if (desc.written)
+		return desc.written;
+	return desc.error;
+}
+
+static int shmem_statfs(struct super_block *sb, struct kstatfs *buf)
+{
+	struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
+
+	buf->f_type = TMPFS_MAGIC;
+	buf->f_bsize = PAGE_CACHE_SIZE;
+	buf->f_namelen = NAME_MAX;
+	if (sbinfo) {
+		spin_lock(&sbinfo->stat_lock);
+		buf->f_blocks = sbinfo->max_blocks;
+		buf->f_bavail = buf->f_bfree = sbinfo->free_blocks;
+		buf->f_files = sbinfo->max_inodes;
+		buf->f_ffree = sbinfo->free_inodes;
+		spin_unlock(&sbinfo->stat_lock);
+	}
+	/* else leave those fields 0 like simple_statfs */
+	return 0;
+}
+
+/*
+ * File creation. Allocate an inode, and we're done..
+ */
+static int
+shmem_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
+{
+	struct inode *inode = shmem_get_inode(dir->i_sb, mode, dev);
+	int error = -ENOSPC;
+
+	if (inode) {
+		if (dir->i_mode & S_ISGID) {
+			inode->i_gid = dir->i_gid;
+			if (S_ISDIR(mode))
+				inode->i_mode |= S_ISGID;
+		}
+		dir->i_size += BOGO_DIRENT_SIZE;
+		dir->i_ctime = dir->i_mtime = CURRENT_TIME;
+		d_instantiate(dentry, inode);
+		dget(dentry); /* Extra count - pin the dentry in core */
+		error = 0;
+	}
+	return error;
+}
+
+static int shmem_mkdir(struct inode *dir, struct dentry *dentry, int mode)
+{
+	int error;
+
+	if ((error = shmem_mknod(dir, dentry, mode | S_IFDIR, 0)))
+		return error;
+	dir->i_nlink++;
+	return 0;
+}
+
+static int shmem_create(struct inode *dir, struct dentry *dentry, int mode,
+		struct nameidata *nd)
+{
+	return shmem_mknod(dir, dentry, mode | S_IFREG, 0);
+}
+
+/*
+ * Link a file..
+ */
+static int shmem_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry)
+{
+	struct inode *inode = old_dentry->d_inode;
+	struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
+
+	/*
+	 * No ordinary (disk based) filesystem counts links as inodes;
+	 * but each new link needs a new dentry, pinning lowmem, and
+	 * tmpfs dentries cannot be pruned until they are unlinked.
+	 */
+	if (sbinfo) {
+		spin_lock(&sbinfo->stat_lock);
+		if (!sbinfo->free_inodes) {
+			spin_unlock(&sbinfo->stat_lock);
+			return -ENOSPC;
+		}
+		sbinfo->free_inodes--;
+		spin_unlock(&sbinfo->stat_lock);
+	}
+
+	dir->i_size += BOGO_DIRENT_SIZE;
+	inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
+	inode->i_nlink++;
+	atomic_inc(&inode->i_count);	/* New dentry reference */
+	dget(dentry);		/* Extra pinning count for the created dentry */
+	d_instantiate(dentry, inode);
+	return 0;
+}
+
+static int shmem_unlink(struct inode *dir, struct dentry *dentry)
+{
+	struct inode *inode = dentry->d_inode;
+
+	if (inode->i_nlink > 1 && !S_ISDIR(inode->i_mode)) {
+		struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
+		if (sbinfo) {
+			spin_lock(&sbinfo->stat_lock);
+			sbinfo->free_inodes++;
+			spin_unlock(&sbinfo->stat_lock);
+		}
+	}
+
+	dir->i_size -= BOGO_DIRENT_SIZE;
+	inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
+	inode->i_nlink--;
+	dput(dentry);	/* Undo the count from "create" - this does all the work */
+	return 0;
+}
+
+static int shmem_rmdir(struct inode *dir, struct dentry *dentry)
+{
+	if (!simple_empty(dentry))
+		return -ENOTEMPTY;
+
+	dir->i_nlink--;
+	return shmem_unlink(dir, dentry);
+}
+
+/*
+ * The VFS layer already does all the dentry stuff for rename,
+ * we just have to decrement the usage count for the target if
+ * it exists so that the VFS layer correctly free's it when it
+ * gets overwritten.
+ */
+static int shmem_rename(struct inode *old_dir, struct dentry *old_dentry, struct inode *new_dir, struct dentry *new_dentry)
+{
+	struct inode *inode = old_dentry->d_inode;
+	int they_are_dirs = S_ISDIR(inode->i_mode);
+
+	if (!simple_empty(new_dentry))
+		return -ENOTEMPTY;
+
+	if (new_dentry->d_inode) {
+		(void) shmem_unlink(new_dir, new_dentry);
+		if (they_are_dirs)
+			old_dir->i_nlink--;
+	} else if (they_are_dirs) {
+		old_dir->i_nlink--;
+		new_dir->i_nlink++;
+	}
+
+	old_dir->i_size -= BOGO_DIRENT_SIZE;
+	new_dir->i_size += BOGO_DIRENT_SIZE;
+	old_dir->i_ctime = old_dir->i_mtime =
+	new_dir->i_ctime = new_dir->i_mtime =
+	inode->i_ctime = CURRENT_TIME;
+	return 0;
+}
+
+static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
+{
+	int error;
+	int len;
+	struct inode *inode;
+	struct page *page = NULL;
+	char *kaddr;
+	struct shmem_inode_info *info;
+
+	len = strlen(symname) + 1;
+	if (len > PAGE_CACHE_SIZE)
+		return -ENAMETOOLONG;
+
+	inode = shmem_get_inode(dir->i_sb, S_IFLNK|S_IRWXUGO, 0);
+	if (!inode)
+		return -ENOSPC;
+
+	info = SHMEM_I(inode);
+	inode->i_size = len-1;
+	if (len <= (char *)inode - (char *)info) {
+		/* do it inline */
+		memcpy(info, symname, len);
+		inode->i_op = &shmem_symlink_inline_operations;
+	} else {
+		error = shmem_getpage(inode, 0, &page, SGP_WRITE, NULL);
+		if (error) {
+			iput(inode);
+			return error;
+		}
+		inode->i_op = &shmem_symlink_inode_operations;
+		kaddr = kmap_atomic(page, KM_USER0);
+		memcpy(kaddr, symname, len);
+		kunmap_atomic(kaddr, KM_USER0);
+		set_page_dirty(page);
+		page_cache_release(page);
+	}
+	if (dir->i_mode & S_ISGID)
+		inode->i_gid = dir->i_gid;
+	dir->i_size += BOGO_DIRENT_SIZE;
+	dir->i_ctime = dir->i_mtime = CURRENT_TIME;
+	d_instantiate(dentry, inode);
+	dget(dentry);
+	return 0;
+}
+
+static int shmem_follow_link_inline(struct dentry *dentry, struct nameidata *nd)
+{
+	nd_set_link(nd, (char *)SHMEM_I(dentry->d_inode));
+	return 0;
+}
+
+static int shmem_follow_link(struct dentry *dentry, struct nameidata *nd)
+{
+	struct page *page = NULL;
+	int res = shmem_getpage(dentry->d_inode, 0, &page, SGP_READ, NULL);
+	nd_set_link(nd, res ? ERR_PTR(res) : kmap(page));
+	return 0;
+}
+
+static void shmem_put_link(struct dentry *dentry, struct nameidata *nd)
+{
+	if (!IS_ERR(nd_get_link(nd))) {
+		struct page *page;
+
+		page = find_get_page(dentry->d_inode->i_mapping, 0);
+		if (!page)
+			BUG();
+		kunmap(page);
+		mark_page_accessed(page);
+		page_cache_release(page);
+		page_cache_release(page);
+	}
+}
+
+static struct inode_operations shmem_symlink_inline_operations = {
+	.readlink	= generic_readlink,
+	.follow_link	= shmem_follow_link_inline,
+#ifdef CONFIG_TMPFS_XATTR
+	.setxattr       = generic_setxattr,
+	.getxattr       = generic_getxattr,
+	.listxattr      = generic_listxattr,
+	.removexattr    = generic_removexattr,
+#endif
+};
+
+static struct inode_operations shmem_symlink_inode_operations = {
+	.truncate	= shmem_truncate,
+	.readlink	= generic_readlink,
+	.follow_link	= shmem_follow_link,
+	.put_link	= shmem_put_link,
+#ifdef CONFIG_TMPFS_XATTR
+	.setxattr       = generic_setxattr,
+	.getxattr       = generic_getxattr,
+	.listxattr      = generic_listxattr,
+	.removexattr    = generic_removexattr,
+#endif
+};
+
+static int shmem_parse_options(char *options, int *mode, uid_t *uid, gid_t *gid, unsigned long *blocks, unsigned long *inodes)
+{
+	char *this_char, *value, *rest;
+
+	while ((this_char = strsep(&options, ",")) != NULL) {
+		if (!*this_char)
+			continue;
+		if ((value = strchr(this_char,'=')) != NULL) {
+			*value++ = 0;
+		} else {
+			printk(KERN_ERR
+			    "tmpfs: No value for mount option '%s'\n",
+			    this_char);
+			return 1;
+		}
+
+		if (!strcmp(this_char,"size")) {
+			unsigned long long size;
+			size = memparse(value,&rest);
+			if (*rest == '%') {
+				size <<= PAGE_SHIFT;
+				size *= totalram_pages;
+				do_div(size, 100);
+				rest++;
+			}
+			if (*rest)
+				goto bad_val;
+			*blocks = size >> PAGE_CACHE_SHIFT;
+		} else if (!strcmp(this_char,"nr_blocks")) {
+			*blocks = memparse(value,&rest);
+			if (*rest)
+				goto bad_val;
+		} else if (!strcmp(this_char,"nr_inodes")) {
+			*inodes = memparse(value,&rest);
+			if (*rest)
+				goto bad_val;
+		} else if (!strcmp(this_char,"mode")) {
+			if (!mode)
+				continue;
+			*mode = simple_strtoul(value,&rest,8);
+			if (*rest)
+				goto bad_val;
+		} else if (!strcmp(this_char,"uid")) {
+			if (!uid)
+				continue;
+			*uid = simple_strtoul(value,&rest,0);
+			if (*rest)
+				goto bad_val;
+		} else if (!strcmp(this_char,"gid")) {
+			if (!gid)
+				continue;
+			*gid = simple_strtoul(value,&rest,0);
+			if (*rest)
+				goto bad_val;
+		} else {
+			printk(KERN_ERR "tmpfs: Bad mount option %s\n",
+			       this_char);
+			return 1;
+		}
+	}
+	return 0;
+
+bad_val:
+	printk(KERN_ERR "tmpfs: Bad value '%s' for mount option '%s'\n",
+	       value, this_char);
+	return 1;
+
+}
+
+static int shmem_remount_fs(struct super_block *sb, int *flags, char *data)
+{
+	struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
+	unsigned long max_blocks = 0;
+	unsigned long max_inodes = 0;
+
+	if (sbinfo) {
+		max_blocks = sbinfo->max_blocks;
+		max_inodes = sbinfo->max_inodes;
+	}
+	if (shmem_parse_options(data, NULL, NULL, NULL, &max_blocks, &max_inodes))
+		return -EINVAL;
+	/* Keep it simple: disallow limited <-> unlimited remount */
+	if ((max_blocks || max_inodes) == !sbinfo)
+		return -EINVAL;
+	/* But allow the pointless unlimited -> unlimited remount */
+	if (!sbinfo)
+		return 0;
+	return shmem_set_size(sbinfo, max_blocks, max_inodes);
+}
+#endif
+
+static void shmem_put_super(struct super_block *sb)
+{
+	kfree(sb->s_fs_info);
+	sb->s_fs_info = NULL;
+}
+
+#ifdef CONFIG_TMPFS_XATTR
+static struct xattr_handler *shmem_xattr_handlers[];
+#else
+#define shmem_xattr_handlers NULL
+#endif
+
+static int shmem_fill_super(struct super_block *sb,
+			    void *data, int silent)
+{
+	struct inode *inode;
+	struct dentry *root;
+	int mode   = S_IRWXUGO | S_ISVTX;
+	uid_t uid = current->fsuid;
+	gid_t gid = current->fsgid;
+	int err = -ENOMEM;
+
+#ifdef CONFIG_TMPFS
+	unsigned long blocks = 0;
+	unsigned long inodes = 0;
+
+	/*
+	 * Per default we only allow half of the physical ram per
+	 * tmpfs instance, limiting inodes to one per page of lowmem;
+	 * but the internal instance is left unlimited.
+	 */
+	if (!(sb->s_flags & MS_NOUSER)) {
+		blocks = totalram_pages / 2;
+		inodes = totalram_pages - totalhigh_pages;
+		if (inodes > blocks)
+			inodes = blocks;
+
+		if (shmem_parse_options(data, &mode,
+					&uid, &gid, &blocks, &inodes))
+			return -EINVAL;
+	}
+
+	if (blocks || inodes) {
+		struct shmem_sb_info *sbinfo;
+		sbinfo = kmalloc(sizeof(struct shmem_sb_info), GFP_KERNEL);
+		if (!sbinfo)
+			return -ENOMEM;
+		sb->s_fs_info = sbinfo;
+		spin_lock_init(&sbinfo->stat_lock);
+		sbinfo->max_blocks = blocks;
+		sbinfo->free_blocks = blocks;
+		sbinfo->max_inodes = inodes;
+		sbinfo->free_inodes = inodes;
+	}
+	sb->s_xattr = shmem_xattr_handlers;
+#else
+	sb->s_flags |= MS_NOUSER;
+#endif
+
+	sb->s_maxbytes = SHMEM_MAX_BYTES;
+	sb->s_blocksize = PAGE_CACHE_SIZE;
+	sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
+	sb->s_magic = TMPFS_MAGIC;
+	sb->s_op = &shmem_ops;
+	inode = shmem_get_inode(sb, S_IFDIR | mode, 0);
+	if (!inode)
+		goto failed;
+	inode->i_uid = uid;
+	inode->i_gid = gid;
+	root = d_alloc_root(inode);
+	if (!root)
+		goto failed_iput;
+	sb->s_root = root;
+	return 0;
+
+failed_iput:
+	iput(inode);
+failed:
+	shmem_put_super(sb);
+	return err;
+}
+
+static kmem_cache_t *shmem_inode_cachep;
+
+static struct inode *shmem_alloc_inode(struct super_block *sb)
+{
+	struct shmem_inode_info *p;
+	p = (struct shmem_inode_info *)kmem_cache_alloc(shmem_inode_cachep, SLAB_KERNEL);
+	if (!p)
+		return NULL;
+	return &p->vfs_inode;
+}
+
+static void shmem_destroy_inode(struct inode *inode)
+{
+	if ((inode->i_mode & S_IFMT) == S_IFREG) {
+		/* only struct inode is valid if it's an inline symlink */
+		mpol_free_shared_policy(&SHMEM_I(inode)->policy);
+	}
+	kmem_cache_free(shmem_inode_cachep, SHMEM_I(inode));
+}
+
+static void init_once(void *foo, kmem_cache_t *cachep, unsigned long flags)
+{
+	struct shmem_inode_info *p = (struct shmem_inode_info *) foo;
+
+	if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
+	    SLAB_CTOR_CONSTRUCTOR) {
+		inode_init_once(&p->vfs_inode);
+	}
+}
+
+static int init_inodecache(void)
+{
+	shmem_inode_cachep = kmem_cache_create("shmem_inode_cache",
+				sizeof(struct shmem_inode_info),
+				0, 0, init_once, NULL);
+	if (shmem_inode_cachep == NULL)
+		return -ENOMEM;
+	return 0;
+}
+
+static void destroy_inodecache(void)
+{
+	if (kmem_cache_destroy(shmem_inode_cachep))
+		printk(KERN_INFO "shmem_inode_cache: not all structures were freed\n");
+}
+
+static struct address_space_operations shmem_aops = {
+	.writepage	= shmem_writepage,
+	.set_page_dirty	= __set_page_dirty_nobuffers,
+#ifdef CONFIG_TMPFS
+	.prepare_write	= shmem_prepare_write,
+	.commit_write	= simple_commit_write,
+#endif
+};
+
+static struct file_operations shmem_file_operations = {
+	.mmap		= shmem_mmap,
+#ifdef CONFIG_TMPFS
+	.llseek		= generic_file_llseek,
+	.read		= shmem_file_read,
+	.write		= shmem_file_write,
+	.fsync		= simple_sync_file,
+	.sendfile	= shmem_file_sendfile,
+#endif
+};
+
+static struct inode_operations shmem_inode_operations = {
+	.truncate	= shmem_truncate,
+	.setattr	= shmem_notify_change,
+#ifdef CONFIG_TMPFS_XATTR
+	.setxattr       = generic_setxattr,
+	.getxattr       = generic_getxattr,
+	.listxattr      = generic_listxattr,
+	.removexattr    = generic_removexattr,
+#endif
+};
+
+static struct inode_operations shmem_dir_inode_operations = {
+#ifdef CONFIG_TMPFS
+	.create		= shmem_create,
+	.lookup		= simple_lookup,
+	.link		= shmem_link,
+	.unlink		= shmem_unlink,
+	.symlink	= shmem_symlink,
+	.mkdir		= shmem_mkdir,
+	.rmdir		= shmem_rmdir,
+	.mknod		= shmem_mknod,
+	.rename		= shmem_rename,
+#ifdef CONFIG_TMPFS_XATTR
+	.setxattr       = generic_setxattr,
+	.getxattr       = generic_getxattr,
+	.listxattr      = generic_listxattr,
+	.removexattr    = generic_removexattr,
+#endif
+#endif
+};
+
+static struct inode_operations shmem_special_inode_operations = {
+#ifdef CONFIG_TMPFS_XATTR
+	.setxattr	= generic_setxattr,
+	.getxattr	= generic_getxattr,
+	.listxattr	= generic_listxattr,
+	.removexattr	= generic_removexattr,
+#endif
+};
+
+static struct super_operations shmem_ops = {
+	.alloc_inode	= shmem_alloc_inode,
+	.destroy_inode	= shmem_destroy_inode,
+#ifdef CONFIG_TMPFS
+	.statfs		= shmem_statfs,
+	.remount_fs	= shmem_remount_fs,
+#endif
+	.delete_inode	= shmem_delete_inode,
+	.drop_inode	= generic_delete_inode,
+	.put_super	= shmem_put_super,
+};
+
+static struct vm_operations_struct shmem_vm_ops = {
+	.nopage		= shmem_nopage,
+	.populate	= shmem_populate,
+#ifdef CONFIG_NUMA
+	.set_policy     = shmem_set_policy,
+	.get_policy     = shmem_get_policy,
+#endif
+};
+
+
+#ifdef CONFIG_TMPFS_SECURITY
+
+static size_t shmem_xattr_security_list(struct inode *inode, char *list, size_t list_len,
+					const char *name, size_t name_len)
+{
+	return security_inode_listsecurity(inode, list, list_len);
+}
+
+static int shmem_xattr_security_get(struct inode *inode, const char *name, void *buffer, size_t size)
+{
+	if (strcmp(name, "") == 0)
+		return -EINVAL;
+	return security_inode_getsecurity(inode, name, buffer, size);
+}
+
+static int shmem_xattr_security_set(struct inode *inode, const char *name, const void *value, size_t size, int flags)
+{
+	if (strcmp(name, "") == 0)
+		return -EINVAL;
+	return security_inode_setsecurity(inode, name, value, size, flags);
+}
+
+static struct xattr_handler shmem_xattr_security_handler = {
+	.prefix	= XATTR_SECURITY_PREFIX,
+	.list	= shmem_xattr_security_list,
+	.get	= shmem_xattr_security_get,
+	.set	= shmem_xattr_security_set,
+};
+
+#endif	/* CONFIG_TMPFS_SECURITY */
+
+#ifdef CONFIG_TMPFS_XATTR
+
+static struct xattr_handler *shmem_xattr_handlers[] = {
+#ifdef CONFIG_TMPFS_SECURITY
+	&shmem_xattr_security_handler,
+#endif
+	NULL
+};
+
+#endif	/* CONFIG_TMPFS_XATTR */
+
+static struct super_block *shmem_get_sb(struct file_system_type *fs_type,
+	int flags, const char *dev_name, void *data)
+{
+	return get_sb_nodev(fs_type, flags, data, shmem_fill_super);
+}
+
+static struct file_system_type tmpfs_fs_type = {
+	.owner		= THIS_MODULE,
+	.name		= "tmpfs",
+	.get_sb		= shmem_get_sb,
+	.kill_sb	= kill_litter_super,
+};
+static struct vfsmount *shm_mnt;
+
+static int __init init_tmpfs(void)
+{
+	int error;
+
+	error = init_inodecache();
+	if (error)
+		goto out3;
+
+	error = register_filesystem(&tmpfs_fs_type);
+	if (error) {
+		printk(KERN_ERR "Could not register tmpfs\n");
+		goto out2;
+	}
+#ifdef CONFIG_TMPFS
+	devfs_mk_dir("shm");
+#endif
+	shm_mnt = do_kern_mount(tmpfs_fs_type.name, MS_NOUSER,
+				tmpfs_fs_type.name, NULL);
+	if (IS_ERR(shm_mnt)) {
+		error = PTR_ERR(shm_mnt);
+		printk(KERN_ERR "Could not kern_mount tmpfs\n");
+		goto out1;
+	}
+	return 0;
+
+out1:
+	unregister_filesystem(&tmpfs_fs_type);
+out2:
+	destroy_inodecache();
+out3:
+	shm_mnt = ERR_PTR(error);
+	return error;
+}
+module_init(init_tmpfs)
+
+/*
+ * shmem_file_setup - get an unlinked file living in tmpfs
+ *
+ * @name: name for dentry (to be seen in /proc/<pid>/maps
+ * @size: size to be set for the file
+ *
+ */
+struct file *shmem_file_setup(char *name, loff_t size, unsigned long flags)
+{
+	int error;
+	struct file *file;
+	struct inode *inode;
+	struct dentry *dentry, *root;
+	struct qstr this;
+
+	if (IS_ERR(shm_mnt))
+		return (void *)shm_mnt;
+
+	if (size < 0 || size > SHMEM_MAX_BYTES)
+		return ERR_PTR(-EINVAL);
+
+	if (shmem_acct_size(flags, size))
+		return ERR_PTR(-ENOMEM);
+
+	error = -ENOMEM;
+	this.name = name;
+	this.len = strlen(name);
+	this.hash = 0; /* will go */
+	root = shm_mnt->mnt_root;
+	dentry = d_alloc(root, &this);
+	if (!dentry)
+		goto put_memory;
+
+	error = -ENFILE;
+	file = get_empty_filp();
+	if (!file)
+		goto put_dentry;
+
+	error = -ENOSPC;
+	inode = shmem_get_inode(root->d_sb, S_IFREG | S_IRWXUGO, 0);
+	if (!inode)
+		goto close_file;
+
+	SHMEM_I(inode)->flags = flags & VM_ACCOUNT;
+	d_instantiate(dentry, inode);
+	inode->i_size = size;
+	inode->i_nlink = 0;	/* It is unlinked */
+	file->f_vfsmnt = mntget(shm_mnt);
+	file->f_dentry = dentry;
+	file->f_mapping = inode->i_mapping;
+	file->f_op = &shmem_file_operations;
+	file->f_mode = FMODE_WRITE | FMODE_READ;
+	return file;
+
+close_file:
+	put_filp(file);
+put_dentry:
+	dput(dentry);
+put_memory:
+	shmem_unacct_size(flags, size);
+	return ERR_PTR(error);
+}
+
+/*
+ * shmem_zero_setup - setup a shared anonymous mapping
+ *
+ * @vma: the vma to be mmapped is prepared by do_mmap_pgoff
+ */
+int shmem_zero_setup(struct vm_area_struct *vma)
+{
+	struct file *file;
+	loff_t size = vma->vm_end - vma->vm_start;
+
+	file = shmem_file_setup("dev/zero", size, vma->vm_flags);
+	if (IS_ERR(file))
+		return PTR_ERR(file);
+
+	if (vma->vm_file)
+		fput(vma->vm_file);
+	vma->vm_file = file;
+	vma->vm_ops = &shmem_vm_ops;
+	return 0;
+}