fedora core 6 1.2949 + vserver 2.2.0
[linux-2.6.git] / mm / shmem.c
index 8951a2a..aa4d837 100644 (file)
@@ -6,10 +6,14 @@
  *              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) 2002-2005 Hugh Dickins.
+ * Copyright (C) 2002-2005 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.
  */
 
  * 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/xattr.h>
+#include <linux/generic_acl.h>
 #include <linux/mm.h>
 #include <linux/mman.h>
 #include <linux/file.h>
 #include <linux/swapops.h>
 #include <linux/mempolicy.h>
 #include <linux/namei.h>
+#include <linux/ctype.h>
+#include <linux/migrate.h>
+#include <linux/highmem.h>
+#include <linux/backing-dev.h>
+
 #include <asm/uaccess.h>
 #include <asm/div64.h>
 #include <asm/pgtable.h>
 #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 */
@@ -77,7 +86,7 @@ enum sgp_type {
 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)
+static inline struct page *shmem_dir_alloc(gfp_t gfp_mask)
 {
        /*
         * The above definition of ENTRIES_PER_PAGE, and the use of
@@ -166,28 +175,29 @@ static inline void shmem_unacct_blocks(unsigned long flags, long pages)
 }
 
 static struct super_operations shmem_ops;
-static struct address_space_operations shmem_aops;
-static struct file_operations shmem_file_operations;
+static const struct address_space_operations shmem_aops;
+static const 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 = {
+static struct backing_dev_info shmem_backing_dev_info  __read_mostly = {
        .ra_pages       = 0,    /* No readahead */
-       .memory_backed  = 1,    /* Does not contribute to dirty memory */
-       .unplug_io_fn = default_unplug_io_fn,
+       .capabilities   = BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK,
+       .unplug_io_fn   = default_unplug_io_fn,
 };
 
 static LIST_HEAD(shmem_swaplist);
-static spinlock_t shmem_swaplist_lock = SPIN_LOCK_UNLOCKED;
+static DEFINE_SPINLOCK(shmem_swaplist_lock);
 
-static void shmem_free_block(struct inode *inode)
+static void shmem_free_blocks(struct inode *inode, long pages)
 {
        struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
-       if (sbinfo) {
+       if (sbinfo->max_blocks) {
                spin_lock(&sbinfo->stat_lock);
-               sbinfo->free_blocks++;
-               inode->i_blocks -= BLOCKS_PER_PAGE;
+               sbinfo->free_blocks += pages;
+               inode->i_blocks -= pages*BLOCKS_PER_PAGE;
                spin_unlock(&sbinfo->stat_lock);
        }
 }
@@ -212,15 +222,9 @@ static void shmem_recalc_inode(struct inode *inode)
 
        freed = info->alloced - info->swapped - inode->i_mapping->nrpages;
        if (freed > 0) {
-               struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
                info->alloced -= freed;
                shmem_unacct_blocks(info->flags, freed);
-               if (sbinfo) {
-                       spin_lock(&sbinfo->stat_lock);
-                       sbinfo->free_blocks += freed;
-                       inode->i_blocks -= freed*BLOCKS_PER_PAGE;
-                       spin_unlock(&sbinfo->stat_lock);
-               }
+               shmem_free_blocks(inode, freed);
        }
 }
 
@@ -322,8 +326,10 @@ static void shmem_swp_set(struct shmem_inode_info *info, swp_entry_t *entry, uns
 
        entry->val = value;
        info->swapped += incdec;
-       if ((unsigned long)(entry - info->i_direct) >= SHMEM_NR_DIRECT)
-               kmap_atomic_to_page(entry)->nr_swapped += incdec;
+       if ((unsigned long)(entry - info->i_direct) >= SHMEM_NR_DIRECT) {
+               struct page *page = kmap_atomic_to_page(entry);
+               set_page_private(page, page_private(page) + incdec);
+       }
 }
 
 /*
@@ -353,7 +359,7 @@ static swp_entry_t *shmem_swp_alloc(struct shmem_inode_info *info, unsigned long
                 * page (and perhaps indirect index pages) yet to allocate:
                 * a waste to allocate index if we cannot allocate data.
                 */
-               if (sbinfo) {
+               if (sbinfo->max_blocks) {
                        spin_lock(&sbinfo->stat_lock);
                        if (sbinfo->free_blocks <= 1) {
                                spin_unlock(&sbinfo->stat_lock);
@@ -365,15 +371,13 @@ static swp_entry_t *shmem_swp_alloc(struct shmem_inode_info *info, unsigned long
                }
 
                spin_unlock(&info->lock);
-               page = shmem_dir_alloc(mapping_gfp_mask(inode->i_mapping));
-               if (page) {
-                       clear_highpage(page);
-                       page->nr_swapped = 0;
-               }
+               page = shmem_dir_alloc(mapping_gfp_mask(inode->i_mapping) | __GFP_ZERO);
+               if (page)
+                       set_page_private(page, 0);
                spin_lock(&info->lock);
 
                if (!page) {
-                       shmem_free_block(inode);
+                       shmem_free_blocks(inode, 1);
                        return ERR_PTR(-ENOMEM);
                }
                if (sgp != SGP_WRITE &&
@@ -386,7 +390,7 @@ static swp_entry_t *shmem_swp_alloc(struct shmem_inode_info *info, unsigned long
        }
        if (page) {
                /* another task gave its page, or truncated the file */
-               shmem_free_block(inode);
+               shmem_free_blocks(inode, 1);
                shmem_dir_free(page);
        }
        if (info->next_index <= index && !IS_ERR(entry))
@@ -397,93 +401,209 @@ static swp_entry_t *shmem_swp_alloc(struct shmem_inode_info *info, unsigned long
 /*
  * shmem_free_swp - free some swap entries in a directory
  *
- * @dir:   pointer to the directory
- * @edir:  pointer after last entry of the directory
+ * @dir:        pointer to the directory
+ * @edir:       pointer after last entry of the directory
+ * @punch_lock: pointer to spinlock when needed for the holepunch case
  */
-static int shmem_free_swp(swp_entry_t *dir, swp_entry_t *edir)
+static int shmem_free_swp(swp_entry_t *dir, swp_entry_t *edir,
+                                               spinlock_t *punch_lock)
 {
+       spinlock_t *punch_unlock = NULL;
        swp_entry_t *ptr;
        int freed = 0;
 
        for (ptr = dir; ptr < edir; ptr++) {
                if (ptr->val) {
+                       if (unlikely(punch_lock)) {
+                               punch_unlock = punch_lock;
+                               punch_lock = NULL;
+                               spin_lock(punch_unlock);
+                               if (!ptr->val)
+                                       continue;
+                       }
                        free_swap_and_cache(*ptr);
                        *ptr = (swp_entry_t){0};
                        freed++;
                }
        }
+       if (punch_unlock)
+               spin_unlock(punch_unlock);
        return freed;
 }
 
-static void shmem_truncate(struct inode *inode)
+static int shmem_map_and_free_swp(struct page *subdir, int offset,
+               int limit, struct page ***dir, spinlock_t *punch_lock)
+{
+       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,
+                                                       punch_lock);
+               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_range(struct inode *inode, loff_t start, loff_t end)
 {
        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;
-       struct page *empty;
        swp_entry_t *ptr;
+       LIST_HEAD(pages_to_free);
+       long nr_pages_to_free = 0;
+       long nr_swaps_freed = 0;
        int offset;
        int freed;
+       int punch_hole;
+       spinlock_t *needs_lock;
+       spinlock_t *punch_lock;
+       unsigned long upper_limit;
 
        inode->i_ctime = inode->i_mtime = CURRENT_TIME;
-       idx = (inode->i_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
+       idx = (start + 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;
+       if (likely(end == (loff_t) -1)) {
+               limit = info->next_index;
+               upper_limit = SHMEM_MAX_INDEX;
+               info->next_index = idx;
+               needs_lock = NULL;
+               punch_hole = 0;
+       } else {
+               if (end + 1 >= inode->i_size) { /* we may free a little more */
+                       limit = (inode->i_size + PAGE_CACHE_SIZE - 1) >>
+                                                       PAGE_CACHE_SHIFT;
+                       upper_limit = SHMEM_MAX_INDEX;
+               } else {
+                       limit = (end + 1) >> PAGE_CACHE_SHIFT;
+                       upper_limit = limit;
+               }
+               needs_lock = &info->lock;
+               punch_hole = 1;
+       }
+
+       topdir = info->i_indirect;
+       if (topdir && idx <= SHMEM_NR_DIRECT && !punch_hole) {
+               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;
-               info->swapped -= shmem_free_swp(ptr+idx, ptr+size);
+               nr_swaps_freed = shmem_free_swp(ptr+idx, ptr+size, needs_lock);
        }
-       if (!info->i_indirect)
+
+       /*
+        * If there are no indirect blocks or we are punching a hole
+        * below indirect blocks, nothing to be done.
+        */
+       if (!topdir || limit <= SHMEM_NR_DIRECT)
                goto done2;
 
-       BUG_ON(limit <= SHMEM_NR_DIRECT);
+       /*
+        * The truncation case has already dropped info->lock, and we're safe
+        * because i_size and next_index have already been lowered, preventing
+        * access beyond.  But in the punch_hole case, we still need to take
+        * the lock when updating the swap directory, because there might be
+        * racing accesses by shmem_getpage(SGP_CACHE), shmem_unuse_inode or
+        * shmem_writepage.  However, whenever we find we can remove a whole
+        * directory page (not at the misaligned start or end of the range),
+        * we first NULLify its pointer in the level above, and then have no
+        * need to take the lock when updating its contents: needs_lock and
+        * punch_lock (either pointing to info->lock or NULL) manage this.
+        */
+
+       upper_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;
 
-       empty = NULL;
-       dir = shmem_dir_map(info->i_indirect);
+       dir = shmem_dir_map(topdir);
        stage = ENTRIES_PER_PAGEPAGE/2;
-       if (idx < ENTRIES_PER_PAGEPAGE/2)
-               dir += idx/ENTRIES_PER_PAGE;
-       else {
+       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) {
-                       subdir = *dir;
-                       size = ((idx - ENTRIES_PER_PAGEPAGE/2) %
+                       diroff = ((idx - ENTRIES_PER_PAGEPAGE/2) %
                                ENTRIES_PER_PAGEPAGE) / ENTRIES_PER_PAGE;
-                       if (!size && !offset) {
-                               empty = subdir;
-                               *dir = NULL;
+                       if (!diroff && !offset && upper_limit >= stage) {
+                               if (needs_lock) {
+                                       spin_lock(needs_lock);
+                                       *dir = NULL;
+                                       spin_unlock(needs_lock);
+                                       needs_lock = NULL;
+                               } else
+                                       *dir = NULL;
+                               nr_pages_to_free++;
+                               list_add(&middir->lru, &pages_to_free);
                        }
                        shmem_dir_unmap(dir);
-                       dir = shmem_dir_map(subdir) + size;
+                       dir = shmem_dir_map(middir);
                } else {
+                       diroff = 0;
                        offset = 0;
                        idx = stage;
                }
        }
 
-       for (; idx < limit; idx += ENTRIES_PER_PAGE, dir++) {
+       for (; idx < limit; idx += ENTRIES_PER_PAGE, diroff++) {
                if (unlikely(idx == stage)) {
-                       shmem_dir_unmap(dir-1);
-                       dir = shmem_dir_map(info->i_indirect) +
+                       shmem_dir_unmap(dir);
+                       dir = shmem_dir_map(topdir) +
                            ENTRIES_PER_PAGE/2 + idx/ENTRIES_PER_PAGEPAGE;
                        while (!*dir) {
                                dir++;
@@ -492,50 +612,60 @@ static void shmem_truncate(struct inode *inode)
                                        goto done1;
                        }
                        stage = idx + ENTRIES_PER_PAGEPAGE;
-                       subdir = *dir;
-                       *dir = NULL;
-                       shmem_dir_unmap(dir);
-                       if (empty) {
-                               shmem_dir_free(empty);
-                               shmem_free_block(inode);
+                       middir = *dir;
+                       if (punch_hole)
+                               needs_lock = &info->lock;
+                       if (upper_limit >= stage) {
+                               if (needs_lock) {
+                                       spin_lock(needs_lock);
+                                       *dir = NULL;
+                                       spin_unlock(needs_lock);
+                                       needs_lock = NULL;
+                               } else
+                                       *dir = NULL;
+                               nr_pages_to_free++;
+                               list_add(&middir->lru, &pages_to_free);
                        }
-                       empty = subdir;
-                       cond_resched_lock(&info->lock);
-                       dir = shmem_dir_map(subdir);
+                       shmem_dir_unmap(dir);
+                       cond_resched();
+                       dir = shmem_dir_map(middir);
+                       diroff = 0;
                }
-               subdir = *dir;
-               if (subdir && subdir->nr_swapped) {
-                       ptr = shmem_swp_map(subdir);
+               punch_lock = needs_lock;
+               subdir = dir[diroff];
+               if (subdir && !offset && upper_limit-idx >= ENTRIES_PER_PAGE) {
+                       if (needs_lock) {
+                               spin_lock(needs_lock);
+                               dir[diroff] = NULL;
+                               spin_unlock(needs_lock);
+                               punch_lock = NULL;
+                       } else
+                               dir[diroff] = NULL;
+                       nr_pages_to_free++;
+                       list_add(&subdir->lru, &pages_to_free);
+               }
+               if (subdir && page_private(subdir) /* has swap entries */) {
                        size = limit - idx;
                        if (size > ENTRIES_PER_PAGE)
                                size = ENTRIES_PER_PAGE;
-                       freed = shmem_free_swp(ptr+offset, ptr+size);
-                       shmem_swp_unmap(ptr);
-                       info->swapped -= freed;
-                       subdir->nr_swapped -= freed;
-                       BUG_ON(subdir->nr_swapped > offset);
-               }
-               if (offset)
-                       offset = 0;
-               else if (subdir) {
-                       *dir = NULL;
-                       shmem_dir_free(subdir);
-                       shmem_free_block(inode);
+                       freed = shmem_map_and_free_swp(subdir,
+                                       offset, size, &dir, punch_lock);
+                       if (!dir)
+                               dir = shmem_dir_map(middir);
+                       nr_swaps_freed += freed;
+                       if (offset || punch_lock) {
+                               spin_lock(&info->lock);
+                               set_page_private(subdir,
+                                       page_private(subdir) - freed);
+                               spin_unlock(&info->lock);
+                       } else
+                               BUG_ON(page_private(subdir) != freed);
                }
+               offset = 0;
        }
 done1:
-       shmem_dir_unmap(dir-1);
-       if (empty) {
-               shmem_dir_free(empty);
-               shmem_free_block(inode);
-       }
-       if (info->next_index <= SHMEM_NR_DIRECT) {
-               shmem_dir_free(info->i_indirect);
-               info->i_indirect = NULL;
-               shmem_free_block(inode);
-       }
+       shmem_dir_unmap(dir);
 done2:
-       BUG_ON(info->swapped > info->next_index);
        if (inode->i_mapping->nrpages && (info->flags & SHMEM_PAGEIN)) {
                /*
                 * Call truncate_inode_pages again: racing shmem_unuse_inode
@@ -543,14 +673,38 @@ done2:
                 * 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.
+                *
+                * Recalling truncate_inode_pages_range and unmap_mapping_range
+                * every time for punch_hole (which never got a chance to clear
+                * SHMEM_PAGEIN at the start of vmtruncate_range) is expensive,
+                * yet hardly ever necessary: try to optimize them out later.
                 */
-               spin_unlock(&info->lock);
-               truncate_inode_pages(inode->i_mapping, inode->i_size);
-               spin_lock(&info->lock);
+               truncate_inode_pages_range(inode->i_mapping, start, end);
+               if (punch_hole)
+                       unmap_mapping_range(inode->i_mapping, start,
+                                                       end - start, 1);
        }
+
+       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 void shmem_truncate(struct inode *inode)
+{
+       shmem_truncate_range(inode, inode->i_size, (loff_t)-1);
 }
 
 static int shmem_notify_change(struct dentry *dentry, struct iattr *attr)
@@ -559,7 +713,7 @@ static int shmem_notify_change(struct dentry *dentry, struct iattr *attr)
        struct page *page = NULL;
        int error;
 
-       if (attr->ia_valid & ATTR_SIZE) {
+       if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) {
                if (attr->ia_size < inode->i_size) {
                        /*
                         * If truncating down to a partial page, then
@@ -592,6 +746,10 @@ static int shmem_notify_change(struct dentry *dentry, struct iattr *attr)
        error = inode_change_ok(inode, attr);
        if (!error)
                error = inode_setattr(inode, attr);
+#ifdef CONFIG_TMPFS_POSIX_ACL
+       if (!error && (attr->ia_valid & ATTR_MODE))
+               error = generic_acl_chmod(inode, &shmem_acl_ops);
+#endif
        if (page)
                page_cache_release(page);
        return error;
@@ -603,6 +761,7 @@ static void shmem_delete_inode(struct inode *inode)
        struct shmem_inode_info *info = SHMEM_I(inode);
 
        if (inode->i_op->truncate == shmem_truncate) {
+               truncate_inode_pages(inode->i_mapping, 0);
                shmem_unacct_size(info->flags, inode->i_size);
                inode->i_size = 0;
                shmem_truncate(inode);
@@ -612,8 +771,8 @@ static void shmem_delete_inode(struct inode *inode)
                        spin_unlock(&shmem_swaplist_lock);
                }
        }
-       if (sbinfo) {
-               BUG_ON(inode->i_blocks);
+       BUG_ON(inode->i_blocks);
+       if (sbinfo->max_inodes) {
                spin_lock(&sbinfo->stat_lock);
                sbinfo->free_inodes++;
                spin_unlock(&sbinfo->stat_lock);
@@ -658,9 +817,6 @@ static int shmem_unuse_inode(struct shmem_inode_info *info, swp_entry_t entry, s
        }
        if (!info->i_indirect)
                goto lost2;
-       /* we might be racing with shmem_truncate */
-       if (limit <= SHMEM_NR_DIRECT)
-               goto lost2;
 
        dir = shmem_dir_map(info->i_indirect);
        stage = SHMEM_NR_DIRECT + ENTRIES_PER_PAGEPAGE/2;
@@ -682,7 +838,7 @@ static int shmem_unuse_inode(struct shmem_inode_info *info, swp_entry_t entry, s
                        dir = shmem_dir_map(subdir);
                }
                subdir = *dir;
-               if (subdir && subdir->nr_swapped) {
+               if (subdir && page_private(subdir)) {
                        ptr = shmem_swp_map(subdir);
                        size = limit - idx;
                        if (size > ENTRIES_PER_PAGE)
@@ -796,10 +952,55 @@ unlock:
        swap_free(swap);
 redirty:
        set_page_dirty(page);
-       return WRITEPAGE_ACTIVATE;      /* Return with the page locked */
+       return AOP_WRITEPAGE_ACTIVATE;  /* Return with the page locked */
 }
 
 #ifdef CONFIG_NUMA
+static inline int shmem_parse_mpol(char *value, int *policy, nodemask_t *policy_nodes)
+{
+       char *nodelist = strchr(value, ':');
+       int err = 1;
+
+       if (nodelist) {
+               /* NUL-terminate policy string */
+               *nodelist++ = '\0';
+               if (nodelist_parse(nodelist, *policy_nodes))
+                       goto out;
+       }
+       if (!strcmp(value, "default")) {
+               *policy = MPOL_DEFAULT;
+               /* Don't allow a nodelist */
+               if (!nodelist)
+                       err = 0;
+       } else if (!strcmp(value, "prefer")) {
+               *policy = MPOL_PREFERRED;
+               /* Insist on a nodelist of one node only */
+               if (nodelist) {
+                       char *rest = nodelist;
+                       while (isdigit(*rest))
+                               rest++;
+                       if (!*rest)
+                               err = 0;
+               }
+       } else if (!strcmp(value, "bind")) {
+               *policy = MPOL_BIND;
+               /* Insist on a nodelist */
+               if (nodelist)
+                       err = 0;
+       } else if (!strcmp(value, "interleave")) {
+               *policy = MPOL_INTERLEAVE;
+               /* Default to nodes online if no nodelist */
+               if (!nodelist)
+                       *policy_nodes = node_online_map;
+               err = 0;
+       }
+out:
+       /* Restore string for error message */
+       if (nodelist)
+               *--nodelist = ':';
+       return err;
+}
+
 static struct page *shmem_swapin_async(struct shared_policy *p,
                                       swp_entry_t entry, unsigned long idx)
 {
@@ -837,7 +1038,7 @@ struct page *shmem_swapin(struct shmem_inode_info *info, swp_entry_t entry,
 }
 
 static struct page *
-shmem_alloc_page(unsigned long gfp, struct shmem_inode_info *info,
+shmem_alloc_page(gfp_t gfp, struct shmem_inode_info *info,
                 unsigned long idx)
 {
        struct vm_area_struct pvma;
@@ -847,11 +1048,16 @@ shmem_alloc_page(unsigned long gfp, struct shmem_inode_info *info,
        pvma.vm_policy = mpol_shared_policy_lookup(&info->policy, idx);
        pvma.vm_pgoff = idx;
        pvma.vm_end = PAGE_SIZE;
-       page = alloc_page_vma(gfp, &pvma, 0);
+       page = alloc_page_vma(gfp | __GFP_ZERO, &pvma, 0);
        mpol_free(pvma.vm_policy);
        return page;
 }
 #else
+static inline int shmem_parse_mpol(char *value, int *policy, nodemask_t *policy_nodes)
+{
+       return 1;
+}
+
 static inline struct page *
 shmem_swapin(struct shmem_inode_info *info,swp_entry_t entry,unsigned long idx)
 {
@@ -860,10 +1066,9 @@ shmem_swapin(struct shmem_inode_info *info,swp_entry_t entry,unsigned long idx)
 }
 
 static inline struct page *
-shmem_alloc_page(unsigned long gfp,struct shmem_inode_info *info,
-                                unsigned long idx)
+shmem_alloc_page(gfp_t gfp,struct shmem_inode_info *info, unsigned long idx)
 {
-       return alloc_page(gfp);
+       return alloc_page(gfp | __GFP_ZERO);
 }
 #endif
 
@@ -920,12 +1125,12 @@ repeat:
                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);
+                               __count_vm_event(PGMAJFAULT);
                                *type = VM_FAULT_MAJOR;
                        }
+                       spin_unlock(&info->lock);
                        swappage = shmem_swapin(info, swap, idx);
                        if (!swappage) {
                                spin_lock(&info->lock);
@@ -999,7 +1204,7 @@ repeat:
                        page_cache_release(swappage);
                        if (error == -ENOMEM) {
                                /* let kswapd refresh zone for GFP_ATOMICs */
-                               blk_congestion_wait(WRITE, HZ/50);
+                               congestion_wait(WRITE, HZ/50);
                        }
                        goto repeat;
                }
@@ -1018,7 +1223,7 @@ repeat:
        } else {
                shmem_swp_unmap(entry);
                sbinfo = SHMEM_SB(inode->i_sb);
-               if (sbinfo) {
+               if (sbinfo->max_blocks) {
                        spin_lock(&sbinfo->stat_lock);
                        if (sbinfo->free_blocks == 0 ||
                            shmem_acct_block(info->flags)) {
@@ -1043,7 +1248,7 @@ repeat:
                                                    idx);
                        if (!filepage) {
                                shmem_unacct_blocks(info->flags, 1);
-                               shmem_free_block(inode);
+                               shmem_free_blocks(inode, 1);
                                error = -ENOMEM;
                                goto failed;
                        }
@@ -1061,7 +1266,7 @@ repeat:
                                spin_unlock(&info->lock);
                                page_cache_release(filepage);
                                shmem_unacct_blocks(info->flags, 1);
-                               shmem_free_block(inode);
+                               shmem_free_blocks(inode, 1);
                                filepage = NULL;
                                if (error)
                                        goto failed;
@@ -1072,7 +1277,6 @@ repeat:
 
                info->alloced++;
                spin_unlock(&info->lock);
-               clear_highpage(filepage);
                flush_dcache_page(filepage);
                SetPageUptodate(filepage);
        }
@@ -1093,7 +1297,7 @@ failed:
 
 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 inode *inode = vma->vm_file->f_path.dentry->d_inode;
        struct page *page = NULL;
        unsigned long idx;
        int error;
@@ -1101,6 +1305,8 @@ struct page *shmem_nopage(struct vm_area_struct *vma, unsigned long address, int
        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)
@@ -1114,7 +1320,7 @@ 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 inode *inode = vma->vm_file->f_path.dentry->d_inode;
        struct mm_struct *mm = vma->vm_mm;
        enum sgp_type sgp = nonblock? SGP_QUICK: SGP_CACHE;
        unsigned long size;
@@ -1132,6 +1338,7 @@ static int shmem_populate(struct vm_area_struct *vma,
                err = shmem_getpage(inode, pgoff, &page, sgp, NULL);
                if (err)
                        return err;
+               /* Page may still be null, but only if nonblock was set. */
                if (page) {
                        mark_page_accessed(page);
                        err = install_page(mm, vma, addr, page, prot);
@@ -1139,7 +1346,10 @@ static int shmem_populate(struct vm_area_struct *vma,
                                page_cache_release(page);
                                return err;
                        }
-               } else if (nonblock) {
+               } else if (vma->vm_flags & VM_NONLINEAR) {
+                       /* No page was found just because we can't read it in
+                        * now (being here implies nonblock != 0), but the page
+                        * may exist, so set the PTE to fault it in later. */
                        err = install_file_pte(mm, vma, addr, pgoff, prot);
                        if (err)
                                return err;
@@ -1155,14 +1365,14 @@ static int shmem_populate(struct vm_area_struct *vma,
 #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;
+       struct inode *i = vma->vm_file->f_path.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;
+       struct inode *i = vma->vm_file->f_path.dentry->d_inode;
        unsigned long idx;
 
        idx = ((addr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
@@ -1172,7 +1382,7 @@ shmem_get_policy(struct vm_area_struct *vma, unsigned long addr)
 
 int shmem_lock(struct file *file, int lock, struct user_struct *user)
 {
-       struct inode *inode = file->f_dentry->d_inode;
+       struct inode *inode = file->f_path.dentry->d_inode;
        struct shmem_inode_info *info = SHMEM_I(inode);
        int retval = -ENOMEM;
 
@@ -1192,7 +1402,7 @@ out_nomem:
        return retval;
 }
 
-static int shmem_mmap(struct file *file, struct vm_area_struct *vma)
+int shmem_mmap(struct file *file, struct vm_area_struct *vma)
 {
        file_accessed(file);
        vma->vm_ops = &shmem_vm_ops;
@@ -1206,7 +1416,7 @@ shmem_get_inode(struct super_block *sb, int mode, dev_t dev)
        struct shmem_inode_info *info;
        struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
 
-       if (sbinfo) {
+       if (sbinfo->max_inodes) {
                spin_lock(&sbinfo->stat_lock);
                if (!sbinfo->free_inodes) {
                        spin_unlock(&sbinfo->stat_lock);
@@ -1221,65 +1431,52 @@ shmem_get_inode(struct super_block *sb, int mode, dev_t dev)
                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;
+               inode->i_generation = get_seconds();
                info = SHMEM_I(inode);
                memset(info, 0, (char *)inode - (char *)info);
                spin_lock_init(&info->lock);
-               mpol_shared_policy_init(&info->policy);
                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, sbinfo->policy,
+                                                       &sbinfo->policy_nodes);
                        break;
                case S_IFDIR:
-                       inode->i_nlink++;
+                       inc_nlink(inode);
                        /* 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, MPOL_DEFAULT,
+                                               NULL);
                        break;
                }
+       } else if (sbinfo->max_inodes) {
+               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;
 
@@ -1297,7 +1494,7 @@ shmem_prepare_write(struct file *file, struct page *page, unsigned offset, unsig
 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;
+       struct inode    *inode = file->f_path.dentry->d_inode;
        loff_t          pos;
        unsigned long   written;
        ssize_t         err;
@@ -1308,7 +1505,7 @@ shmem_file_write(struct file *file, const char __user *buf, size_t count, loff_t
        if (!access_ok(VERIFY_READ, buf, count))
                return -EFAULT;
 
-       down(&inode->i_sem);
+       mutex_lock(&inode->i_mutex);
 
        pos = *ppos;
        written = 0;
@@ -1317,7 +1514,7 @@ shmem_file_write(struct file *file, const char __user *buf, size_t count, loff_t
        if (err || !count)
                goto out;
 
-       err = remove_suid(file->f_dentry);
+       err = remove_suid(file->f_path.dentry);
        if (err)
                goto out;
 
@@ -1393,13 +1590,13 @@ shmem_file_write(struct file *file, const char __user *buf, size_t count, loff_t
        if (written)
                err = written;
 out:
-       up(&inode->i_sem);
+       mutex_unlock(&inode->i_mutex);
        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 inode *inode = filp->f_path.dentry->d_inode;
        struct address_space *mapping = inode->i_mapping;
        unsigned long index, offset;
 
@@ -1429,7 +1626,7 @@ static void do_shmem_file_read(struct file *filp, loff_t *ppos, read_descriptor_
 
                /*
                 * We must evaluate after, since reads (unlike writes)
-                * are called without i_sem protection against truncate
+                * are called without i_mutex protection against truncate
                 */
                nr = PAGE_CACHE_SIZE;
                i_size = i_size_read(inode);
@@ -1457,8 +1654,10 @@ static void do_shmem_file_read(struct file *filp, loff_t *ppos, read_descriptor_
                         */
                        if (!offset)
                                mark_page_accessed(page);
-               } else
+               } else {
                        page = ZERO_PAGE(0);
+                       page_cache_get(page);
+               }
 
                /*
                 * Ok, we have the page, and it's up-to-date, so
@@ -1527,22 +1726,24 @@ static ssize_t shmem_file_sendfile(struct file *in_file, loff_t *ppos,
        return desc.error;
 }
 
-static int shmem_statfs(struct super_block *sb, struct kstatfs *buf)
+static int shmem_statfs(struct dentry *dentry, struct kstatfs *buf)
 {
-       struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
+       struct shmem_sb_info *sbinfo = SHMEM_SB(dentry->d_sb);
 
        buf->f_type = TMPFS_SUPER_MAGIC;
        buf->f_bsize = PAGE_CACHE_SIZE;
        buf->f_namelen = NAME_MAX;
-       if (sbinfo) {
-               spin_lock(&sbinfo->stat_lock);
+       spin_lock(&sbinfo->stat_lock);
+       if (sbinfo->max_blocks) {
                buf->f_blocks = sbinfo->max_blocks;
                buf->f_bavail = buf->f_bfree = sbinfo->free_blocks;
+       }
+       if (sbinfo->max_inodes) {
                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 */
+       spin_unlock(&sbinfo->stat_lock);
        return 0;
 }
 
@@ -1556,6 +1757,19 @@ shmem_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
        int error = -ENOSPC;
 
        if (inode) {
+               error = security_inode_init_security(inode, dir, NULL, NULL,
+                                                    NULL);
+               if (error) {
+                       if (error != -EOPNOTSUPP) {
+                               iput(inode);
+                               return error;
+                       }
+               }
+               error = shmem_acl_init(inode, dir);
+               if (error) {
+                       iput(inode);
+                       return error;
+               }
                if (dir->i_mode & S_ISGID) {
                        inode->i_gid = dir->i_gid;
                        if (S_ISDIR(mode))
@@ -1565,7 +1779,6 @@ shmem_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
                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;
 }
@@ -1576,7 +1789,7 @@ static int shmem_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 
        if ((error = shmem_mknod(dir, dentry, mode | S_IFDIR, 0)))
                return error;
-       dir->i_nlink++;
+       inc_nlink(dir);
        return 0;
 }
 
@@ -1599,7 +1812,7 @@ static int shmem_link(struct dentry *old_dentry, struct inode *dir, struct dentr
         * but each new link needs a new dentry, pinning lowmem, and
         * tmpfs dentries cannot be pruned until they are unlinked.
         */
-       if (sbinfo) {
+       if (sbinfo->max_inodes) {
                spin_lock(&sbinfo->stat_lock);
                if (!sbinfo->free_inodes) {
                        spin_unlock(&sbinfo->stat_lock);
@@ -1611,7 +1824,7 @@ static int shmem_link(struct dentry *old_dentry, struct inode *dir, struct dentr
 
        dir->i_size += BOGO_DIRENT_SIZE;
        inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
-       inode->i_nlink++;
+       inc_nlink(inode);
        atomic_inc(&inode->i_count);    /* New dentry reference */
        dget(dentry);           /* Extra pinning count for the created dentry */
        d_instantiate(dentry, inode);
@@ -1624,7 +1837,7 @@ static int shmem_unlink(struct inode *dir, struct dentry *dentry)
 
        if (inode->i_nlink > 1 && !S_ISDIR(inode->i_mode)) {
                struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
-               if (sbinfo) {
+               if (sbinfo->max_inodes) {
                        spin_lock(&sbinfo->stat_lock);
                        sbinfo->free_inodes++;
                        spin_unlock(&sbinfo->stat_lock);
@@ -1633,7 +1846,7 @@ static int shmem_unlink(struct inode *dir, struct dentry *dentry)
 
        dir->i_size -= BOGO_DIRENT_SIZE;
        inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
-       inode->i_nlink--;
+       drop_nlink(inode);
        dput(dentry);   /* Undo the count from "create" - this does all the work */
        return 0;
 }
@@ -1643,7 +1856,8 @@ static int shmem_rmdir(struct inode *dir, struct dentry *dentry)
        if (!simple_empty(dentry))
                return -ENOTEMPTY;
 
-       dir->i_nlink--;
+       drop_nlink(dentry->d_inode);
+       drop_nlink(dir);
        return shmem_unlink(dir, dentry);
 }
 
@@ -1664,10 +1878,10 @@ static int shmem_rename(struct inode *old_dir, struct dentry *old_dentry, struct
        if (new_dentry->d_inode) {
                (void) shmem_unlink(new_dir, new_dentry);
                if (they_are_dirs)
-                       old_dir->i_nlink--;
+                       drop_nlink(old_dir);
        } else if (they_are_dirs) {
-               old_dir->i_nlink--;
-               new_dir->i_nlink++;
+               drop_nlink(old_dir);
+               inc_nlink(new_dir);
        }
 
        old_dir->i_size -= BOGO_DIRENT_SIZE;
@@ -1695,6 +1909,16 @@ static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *s
        if (!inode)
                return -ENOSPC;
 
+       error = security_inode_init_security(inode, dir, NULL, NULL,
+                                            NULL);
+       if (error) {
+               if (error != -EOPNOTSUPP) {
+                       iput(inode);
+                       return error;
+               }
+               error = 0;
+       }
+
        info = SHMEM_I(inode);
        inode->i_size = len-1;
        if (len <= (char *)inode - (char *)info) {
@@ -1723,32 +1947,27 @@ static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *s
        return 0;
 }
 
-static int shmem_follow_link_inline(struct dentry *dentry, struct nameidata *nd)
+static void *shmem_follow_link_inline(struct dentry *dentry, struct nameidata *nd)
 {
        nd_set_link(nd, (char *)SHMEM_I(dentry->d_inode));
-       return 0;
+       return NULL;
 }
 
-static int shmem_follow_link(struct dentry *dentry, struct nameidata *nd)
+static void *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;
+       return page;
 }
 
-static void shmem_put_link(struct dentry *dentry, struct nameidata *nd)
+static void shmem_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie)
 {
        if (!IS_ERR(nd_get_link(nd))) {
-               struct page *page;
-
-               page = find_get_page(dentry->d_inode->i_mapping, 0);
-               if (!page)
-                       BUG();
+               struct page *page = cookie;
                kunmap(page);
                mark_page_accessed(page);
                page_cache_release(page);
-               page_cache_release(page);
        }
 }
 
@@ -1764,11 +1983,155 @@ static struct inode_operations shmem_symlink_inode_operations = {
        .put_link       = shmem_put_link,
 };
 
-static int shmem_parse_options(char *options, int *mode, uid_t *uid, gid_t *gid, unsigned long *blocks, unsigned long *inodes)
+#ifdef CONFIG_TMPFS_POSIX_ACL
+/**
+ * Superblocks without xattr inode operations will get security.* xattr
+ * support from the VFS "for free". As soon as we have any other xattrs
+ * like ACLs, we also need to implement the security.* handlers at
+ * filesystem level, though.
+ */
+
+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,
+                                         -EOPNOTSUPP);
+}
+
+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,
+};
+
+static struct xattr_handler *shmem_xattr_handlers[] = {
+       &shmem_xattr_acl_access_handler,
+       &shmem_xattr_acl_default_handler,
+       &shmem_xattr_security_handler,
+       NULL
+};
+#endif
+
+static struct dentry *shmem_get_parent(struct dentry *child)
+{
+       return ERR_PTR(-ESTALE);
+}
+
+static int shmem_match(struct inode *ino, void *vfh)
+{
+       __u32 *fh = vfh;
+       __u64 inum = fh[2];
+       inum = (inum << 32) | fh[1];
+       return ino->i_ino == inum && fh[0] == ino->i_generation;
+}
+
+static struct dentry *shmem_get_dentry(struct super_block *sb, void *vfh)
+{
+       struct dentry *de = NULL;
+       struct inode *inode;
+       __u32 *fh = vfh;
+       __u64 inum = fh[2];
+       inum = (inum << 32) | fh[1];
+
+       inode = ilookup5(sb, (unsigned long)(inum+fh[0]), shmem_match, vfh);
+       if (inode) {
+               de = d_find_alias(inode);
+               iput(inode);
+       }
+
+       return de? de: ERR_PTR(-ESTALE);
+}
+
+static struct dentry *shmem_decode_fh(struct super_block *sb, __u32 *fh,
+               int len, int type,
+               int (*acceptable)(void *context, struct dentry *de),
+               void *context)
+{
+       if (len < 3)
+               return ERR_PTR(-ESTALE);
+
+       return sb->s_export_op->find_exported_dentry(sb, fh, NULL, acceptable,
+                                                       context);
+}
+
+static int shmem_encode_fh(struct dentry *dentry, __u32 *fh, int *len,
+                               int connectable)
+{
+       struct inode *inode = dentry->d_inode;
+
+       if (*len < 3)
+               return 255;
+
+       if (hlist_unhashed(&inode->i_hash)) {
+               /* Unfortunately insert_inode_hash is not idempotent,
+                * so as we hash inodes here rather than at creation
+                * time, we need a lock to ensure we only try
+                * to do it once
+                */
+               static DEFINE_SPINLOCK(lock);
+               spin_lock(&lock);
+               if (hlist_unhashed(&inode->i_hash))
+                       __insert_inode_hash(inode,
+                                           inode->i_ino + inode->i_generation);
+               spin_unlock(&lock);
+       }
+
+       fh[0] = inode->i_generation;
+       fh[1] = inode->i_ino;
+       fh[2] = ((__u64)inode->i_ino) >> 32;
+
+       *len = 3;
+       return 1;
+}
+
+static struct export_operations shmem_export_ops = {
+       .get_parent     = shmem_get_parent,
+       .get_dentry     = shmem_get_dentry,
+       .encode_fh      = shmem_encode_fh,
+       .decode_fh      = shmem_decode_fh,
+};
+
+static int shmem_parse_options(char *options, int *mode, uid_t *uid,
+       gid_t *gid, unsigned long *blocks, unsigned long *inodes,
+       int *policy, nodemask_t *policy_nodes)
 {
        char *this_char, *value, *rest;
 
-       while ((this_char = strsep(&options, ",")) != NULL) {
+       while (options != NULL) {
+               this_char = options;
+               for (;;) {
+                       /*
+                        * NUL-terminate this option: unfortunately,
+                        * mount options form a comma-separated list,
+                        * but mpol's nodelist may also contain commas.
+                        */
+                       options = strchr(options, ',');
+                       if (options == NULL)
+                               break;
+                       options++;
+                       if (!isdigit(*options)) {
+                               options[-1] = '\0';
+                               break;
+                       }
+               }
                if (!*this_char)
                        continue;
                if ((value = strchr(this_char,'=')) != NULL) {
@@ -1818,6 +2181,9 @@ static int shmem_parse_options(char *options, int *mode, uid_t *uid, gid_t *gid,
                        *gid = simple_strtoul(value,&rest,0);
                        if (*rest)
                                goto bad_val;
+               } else if (!strcmp(this_char,"mpol")) {
+                       if (shmem_parse_mpol(value,policy,policy_nodes))
+                               goto bad_val;
                } else {
                        printk(KERN_ERR "tmpfs: Bad mount option %s\n",
                               this_char);
@@ -1836,22 +2202,46 @@ bad_val:
 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;
+       unsigned long max_blocks = sbinfo->max_blocks;
+       unsigned long max_inodes = sbinfo->max_inodes;
+       int policy = sbinfo->policy;
+       nodemask_t policy_nodes = sbinfo->policy_nodes;
+       unsigned long blocks;
+       unsigned long inodes;
+       int error = -EINVAL;
+
+       if (shmem_parse_options(data, NULL, NULL, NULL, &max_blocks,
+                               &max_inodes, &policy, &policy_nodes))
+               return error;
 
-       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);
+       spin_lock(&sbinfo->stat_lock);
+       blocks = sbinfo->max_blocks - sbinfo->free_blocks;
+       inodes = sbinfo->max_inodes - sbinfo->free_inodes;
+       if (max_blocks < blocks)
+               goto out;
+       if (max_inodes < inodes)
+               goto out;
+       /*
+        * Those tests also disallow limited->unlimited while any are in
+        * use, so i_blocks will always be zero when max_blocks is zero;
+        * but we must separately disallow unlimited->limited, because
+        * in that case we have no record of how much is already in use.
+        */
+       if (max_blocks && !sbinfo->max_blocks)
+               goto out;
+       if (max_inodes && !sbinfo->max_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;
+       sbinfo->policy = policy;
+       sbinfo->policy_nodes = policy_nodes;
+out:
+       spin_unlock(&sbinfo->stat_lock);
+       return error;
 }
 #endif
 
@@ -1870,11 +2260,13 @@ static int shmem_fill_super(struct super_block *sb,
        uid_t uid = current->fsuid;
        gid_t gid = current->fsgid;
        int err = -ENOMEM;
-
-#ifdef CONFIG_TMPFS
+       struct shmem_sb_info *sbinfo;
        unsigned long blocks = 0;
        unsigned long inodes = 0;
+       int policy = MPOL_DEFAULT;
+       nodemask_t policy_nodes = node_online_map;
 
+#ifdef CONFIG_TMPFS
        /*
         * Per default we only allow half of the physical ram per
         * tmpfs instance, limiting inodes to one per page of lowmem;
@@ -1885,31 +2277,41 @@ static int shmem_fill_super(struct super_block *sb,
                inodes = totalram_pages - totalhigh_pages;
                if (inodes > blocks)
                        inodes = blocks;
-
-               if (shmem_parse_options(data, &mode,
-                                       &uid, &gid, &blocks, &inodes))
+               if (shmem_parse_options(data, &mode, &uid, &gid, &blocks,
+                                       &inodes, &policy, &policy_nodes))
                        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_export_op = &shmem_export_ops;
+#else
+       sb->s_flags |= MS_NOUSER;
 #endif
 
+       /* Round up to L1_CACHE_BYTES to resist false sharing */
+       sbinfo = kmalloc(max((int)sizeof(struct shmem_sb_info),
+                               L1_CACHE_BYTES), GFP_KERNEL);
+       if (!sbinfo)
+               return -ENOMEM;
+
+       spin_lock_init(&sbinfo->stat_lock);
+       sbinfo->max_blocks = blocks;
+       sbinfo->free_blocks = blocks;
+       sbinfo->max_inodes = inodes;
+       sbinfo->free_inodes = inodes;
+       sbinfo->policy = policy;
+       sbinfo->policy_nodes = policy_nodes;
+
+       sb->s_fs_info = sbinfo;
        sb->s_maxbytes = SHMEM_MAX_BYTES;
        sb->s_blocksize = PAGE_CACHE_SIZE;
        sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
        sb->s_magic = TMPFS_SUPER_MAGIC;
        sb->s_op = &shmem_ops;
+       sb->s_time_gran = 1;
+#ifdef CONFIG_TMPFS_POSIX_ACL
+       sb->s_xattr = shmem_xattr_handlers;
+       sb->s_flags |= MS_POSIXACL;
+#endif
+
        inode = shmem_get_inode(sb, S_IFDIR | mode, 0);
        if (!inode)
                goto failed;
@@ -1928,12 +2330,12 @@ failed:
        return err;
 }
 
-static kmem_cache_t *shmem_inode_cachep;
+static struct kmem_cache *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);
+       p = (struct shmem_inode_info *)kmem_cache_alloc(shmem_inode_cachep, GFP_KERNEL);
        if (!p)
                return NULL;
        return &p->vfs_inode;
@@ -1941,17 +2343,26 @@ static struct inode *shmem_alloc_inode(struct super_block *sb)
 
 static void shmem_destroy_inode(struct inode *inode)
 {
-       mpol_free_shared_policy(&SHMEM_I(inode)->policy);
+       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);
+       }
+       shmem_acl_destroy_inode(inode);
        kmem_cache_free(shmem_inode_cachep, SHMEM_I(inode));
 }
 
-static void init_once(void *foo, kmem_cache_t *cachep, unsigned long flags)
+static void init_once(void *foo, struct kmem_cache *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);
+#ifdef CONFIG_TMPFS_POSIX_ACL
+               p->i_acl = NULL;
+               p->i_default_acl = NULL;
+#endif
        }
 }
 
@@ -1967,20 +2378,20 @@ static int init_inodecache(void)
 
 static void destroy_inodecache(void)
 {
-       if (kmem_cache_destroy(shmem_inode_cachep))
-               printk(KERN_INFO "shmem_inode_cache: not all structures were freed\n");
+       kmem_cache_destroy(shmem_inode_cachep);
 }
 
-static struct address_space_operations shmem_aops = {
+static const 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
+       .migratepage    = migrate_page,
 };
 
-static struct file_operations shmem_file_operations = {
+static const struct file_operations shmem_file_operations = {
        .mmap           = shmem_mmap,
 #ifdef CONFIG_TMPFS
        .llseek         = generic_file_llseek,
@@ -1994,6 +2405,15 @@ static struct file_operations shmem_file_operations = {
 static struct inode_operations shmem_inode_operations = {
        .truncate       = shmem_truncate,
        .setattr        = shmem_notify_change,
+       .truncate_range = shmem_truncate_range,
+#ifdef CONFIG_TMPFS_POSIX_ACL
+       .setxattr       = generic_setxattr,
+       .getxattr       = generic_getxattr,
+       .listxattr      = generic_listxattr,
+       .removexattr    = generic_removexattr,
+       .permission     = shmem_permission,
+#endif
+
 };
 
 static struct inode_operations shmem_dir_inode_operations = {
@@ -2008,6 +2428,25 @@ static struct inode_operations shmem_dir_inode_operations = {
        .mknod          = shmem_mknod,
        .rename         = shmem_rename,
 #endif
+#ifdef CONFIG_TMPFS_POSIX_ACL
+       .setattr        = shmem_notify_change,
+       .setxattr       = generic_setxattr,
+       .getxattr       = generic_getxattr,
+       .listxattr      = generic_listxattr,
+       .removexattr    = generic_removexattr,
+       .permission     = shmem_permission,
+#endif
+};
+
+static struct inode_operations shmem_special_inode_operations = {
+#ifdef CONFIG_TMPFS_POSIX_ACL
+       .setattr        = shmem_notify_change,
+       .setxattr       = generic_setxattr,
+       .getxattr       = generic_getxattr,
+       .listxattr      = generic_listxattr,
+       .removexattr    = generic_removexattr,
+       .permission     = shmem_permission,
+#endif
 };
 
 static struct super_operations shmem_ops = {
@@ -2031,10 +2470,11 @@ static struct vm_operations_struct shmem_vm_ops = {
 #endif
 };
 
-static struct super_block *shmem_get_sb(struct file_system_type *fs_type,
-       int flags, const char *dev_name, void *data)
+
+static int shmem_get_sb(struct file_system_type *fs_type,
+       int flags, const char *dev_name, void *data, struct vfsmount *mnt)
 {
-       return get_sb_nodev(fs_type, flags, data, shmem_fill_super);
+       return get_sb_nodev(fs_type, flags, data, shmem_fill_super, mnt);
 }
 
 static struct file_system_type tmpfs_fs_type = {
@@ -2058,10 +2498,8 @@ static int __init init_tmpfs(void)
                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,
+
+       shm_mnt = vfs_kern_mount(&tmpfs_fs_type, MS_NOUSER,
                                tmpfs_fs_type.name, NULL);
        if (IS_ERR(shm_mnt)) {
                error = PTR_ERR(shm_mnt);
@@ -2127,8 +2565,8 @@ struct file *shmem_file_setup(char *name, loff_t size, unsigned long flags)
        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_path.mnt = mntget(shm_mnt);
+       file->f_path.dentry = dentry;
        file->f_mapping = inode->i_mapping;
        file->f_op = &shmem_file_operations;
        file->f_mode = FMODE_WRITE | FMODE_READ;
@@ -2163,5 +2601,3 @@ int shmem_zero_setup(struct vm_area_struct *vma)
        vma->vm_ops = &shmem_vm_ops;
        return 0;
 }
-
-EXPORT_SYMBOL(shmem_file_setup);