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mm/shmem.c 65.5 KB
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
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  /*
   * 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.
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   * Copyright (C) 2002-2005 Hugh Dickins.
   * Copyright (C) 2002-2005 VERITAS Software Corporation.
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   * 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.
   */
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  #include <linux/module.h>
  #include <linux/init.h>
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  #include <linux/fs.h>
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  #include <linux/xattr.h>
  #include <linux/generic_acl.h>
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  #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>
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  #include <linux/ctype.h>
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  #include <linux/migrate.h>
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  #include <linux/highmem.h>
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  #include <linux/backing-dev.h>
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  #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
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  /* 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);
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  static inline struct page *shmem_dir_alloc(gfp_t gfp_mask)
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  {
  	/*
  	 * 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));
  }
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  static const struct super_operations shmem_ops;
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  static const struct address_space_operations shmem_aops;
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  static const struct file_operations shmem_file_operations;
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  static const struct inode_operations shmem_inode_operations;
  static const struct inode_operations shmem_dir_inode_operations;
  static const struct inode_operations shmem_special_inode_operations;
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  static struct vm_operations_struct shmem_vm_ops;
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  static struct backing_dev_info shmem_backing_dev_info  __read_mostly = {
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  	.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);
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  	if (sbinfo->max_blocks) {
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  		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;
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  	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);
  	}
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  }
  
  /*
   * 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.
  		 */
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  		if (sbinfo->max_blocks) {
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  			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);
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  		if (page)
  			set_page_private(page, 0);
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  		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
   *
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   * @dir:        pointer to the directory
   * @edir:       pointer after last entry of the directory
   * @punch_lock: pointer to spinlock when needed for the holepunch case
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   */
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  static int shmem_free_swp(swp_entry_t *dir, swp_entry_t *edir,
  						spinlock_t *punch_lock)
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  {
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  	spinlock_t *punch_unlock = NULL;
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  	swp_entry_t *ptr;
  	int freed = 0;
  
  	for (ptr = dir; ptr < edir; ptr++) {
  		if (ptr->val) {
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  			if (unlikely(punch_lock)) {
  				punch_unlock = punch_lock;
  				punch_lock = NULL;
  				spin_lock(punch_unlock);
  				if (!ptr->val)
  					continue;
  			}
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  			free_swap_and_cache(*ptr);
  			*ptr = (swp_entry_t){0};
  			freed++;
  		}
  	}
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  	if (punch_unlock)
  		spin_unlock(punch_unlock);
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  	return freed;
  }
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  static int shmem_map_and_free_swp(struct page *subdir, int offset,
  		int limit, struct page ***dir, spinlock_t *punch_lock)
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  {
  	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;
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  		freed += shmem_free_swp(ptr+offset, ptr+offset+size,
  							punch_lock);
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  		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);
  }
f6b3ec238   Badari Pulavarty   [PATCH] madvise(M...
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  static void shmem_truncate_range(struct inode *inode, loff_t start, loff_t end)
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  {
  	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;
a2646d1e6   Hugh Dickins   [PATCH] holepunch...
490
  	int punch_hole;
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491
492
  	spinlock_t *needs_lock;
  	spinlock_t *punch_lock;
a2646d1e6   Hugh Dickins   [PATCH] holepunch...
493
  	unsigned long upper_limit;
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  	inode->i_ctime = inode->i_mtime = CURRENT_TIME;
f6b3ec238   Badari Pulavarty   [PATCH] madvise(M...
496
  	idx = (start + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
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  	if (idx >= info->next_index)
  		return;
  
  	spin_lock(&info->lock);
  	info->flags |= SHMEM_TRUNCATE;
f6b3ec238   Badari Pulavarty   [PATCH] madvise(M...
502
503
  	if (likely(end == (loff_t) -1)) {
  		limit = info->next_index;
a2646d1e6   Hugh Dickins   [PATCH] holepunch...
504
  		upper_limit = SHMEM_MAX_INDEX;
f6b3ec238   Badari Pulavarty   [PATCH] madvise(M...
505
  		info->next_index = idx;
1ae700063   Hugh Dickins   [PATCH] holepunch...
506
  		needs_lock = NULL;
a2646d1e6   Hugh Dickins   [PATCH] holepunch...
507
  		punch_hole = 0;
f6b3ec238   Badari Pulavarty   [PATCH] madvise(M...
508
  	} else {
a2646d1e6   Hugh Dickins   [PATCH] holepunch...
509
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516
  		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;
  		}
1ae700063   Hugh Dickins   [PATCH] holepunch...
517
  		needs_lock = &info->lock;
f6b3ec238   Badari Pulavarty   [PATCH] madvise(M...
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519
  		punch_hole = 1;
  	}
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
520
  	topdir = info->i_indirect;
f6b3ec238   Badari Pulavarty   [PATCH] madvise(M...
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  	if (topdir && idx <= SHMEM_NR_DIRECT && !punch_hole) {
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
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  		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;
1ae700063   Hugh Dickins   [PATCH] holepunch...
533
  		nr_swaps_freed = shmem_free_swp(ptr+idx, ptr+size, needs_lock);
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
534
  	}
92a3d03aa   Badari Pulavarty   [PATCH] Fix for s...
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  	/*
  	 * If there are no indirect blocks or we are punching a hole
  	 * below indirect blocks, nothing to be done.
  	 */
a2646d1e6   Hugh Dickins   [PATCH] holepunch...
540
  	if (!topdir || limit <= SHMEM_NR_DIRECT)
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
541
  		goto done2;
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  	/*
  	 * 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.
  	 */
a2646d1e6   Hugh Dickins   [PATCH] holepunch...
554
  	upper_limit -= SHMEM_NR_DIRECT;
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  	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;
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  			if (!diroff && !offset && upper_limit >= stage) {
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  				if (needs_lock) {
  					spin_lock(needs_lock);
  					*dir = NULL;
  					spin_unlock(needs_lock);
  					needs_lock = NULL;
  				} else
  					*dir = NULL;
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  				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;
1ae700063   Hugh Dickins   [PATCH] holepunch...
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  			if (punch_hole)
  				needs_lock = &info->lock;
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  			if (upper_limit >= stage) {
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  				if (needs_lock) {
  					spin_lock(needs_lock);
  					*dir = NULL;
  					spin_unlock(needs_lock);
  					needs_lock = NULL;
  				} else
  					*dir = NULL;
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  				nr_pages_to_free++;
  				list_add(&middir->lru, &pages_to_free);
  			}
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  			shmem_dir_unmap(dir);
  			cond_resched();
  			dir = shmem_dir_map(middir);
  			diroff = 0;
  		}
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  		punch_lock = needs_lock;
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
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  		subdir = dir[diroff];
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  		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 */) {
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
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  			size = limit - idx;
  			if (size > ENTRIES_PER_PAGE)
  				size = ENTRIES_PER_PAGE;
  			freed = shmem_map_and_free_swp(subdir,
1ae700063   Hugh Dickins   [PATCH] holepunch...
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  					offset, size, &dir, punch_lock);
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
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  			if (!dir)
  				dir = shmem_dir_map(middir);
  			nr_swaps_freed += freed;
1ae700063   Hugh Dickins   [PATCH] holepunch...
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  			if (offset || punch_lock) {
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
648
  				spin_lock(&info->lock);
1ae700063   Hugh Dickins   [PATCH] holepunch...
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  				set_page_private(subdir,
  					page_private(subdir) - freed);
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
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  				spin_unlock(&info->lock);
1ae700063   Hugh Dickins   [PATCH] holepunch...
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  			} else
  				BUG_ON(page_private(subdir) != freed);
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
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  		}
1ae700063   Hugh Dickins   [PATCH] holepunch...
655
  		offset = 0;
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
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  	}
  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.
16a100190   Hugh Dickins   [PATCH] holepunch...
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  		 *
  		 * 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.
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
672
  		 */
f6b3ec238   Badari Pulavarty   [PATCH] madvise(M...
673
  		truncate_inode_pages_range(inode->i_mapping, start, end);
16a100190   Hugh Dickins   [PATCH] holepunch...
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  		if (punch_hole)
  			unmap_mapping_range(inode->i_mapping, start,
  							end - start, 1);
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
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  	}
  
  	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);
  	}
  }
f6b3ec238   Badari Pulavarty   [PATCH] madvise(M...
695
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697
698
  static void shmem_truncate(struct inode *inode)
  {
  	shmem_truncate_range(inode, inode->i_size, (loff_t)-1);
  }
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
699
700
701
702
703
  static int shmem_notify_change(struct dentry *dentry, struct iattr *attr)
  {
  	struct inode *inode = dentry->d_inode;
  	struct page *page = NULL;
  	int error;
39f0247d3   Andreas Gruenbacher   [PATCH] Access Co...
704
  	if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) {
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
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  		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);
39f0247d3   Andreas Gruenbacher   [PATCH] Access Co...
737
738
739
740
  #ifdef CONFIG_TMPFS_POSIX_ACL
  	if (!error && (attr->ia_valid & ATTR_MODE))
  		error = generic_acl_chmod(inode, &shmem_acl_ops);
  #endif
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
741
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743
744
745
746
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751
  	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) {
fef266580   Mark Fasheh   [PATCH] update fi...
752
  		truncate_inode_pages(inode->i_mapping, 0);
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
753
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  		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);
  		}
  	}
0edd73b33   Hugh Dickins   [PATCH] shmem: re...
762
763
  	BUG_ON(inode->i_blocks);
  	if (sbinfo->max_inodes) {
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
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  		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;
4c21e2f24   Hugh Dickins   [PATCH] mm: split...
829
  		if (subdir && page_private(subdir)) {
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
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  			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);
994fc28c7   Zach Brown   [PATCH] add AOP_T...
943
  	return AOP_WRITEPAGE_ACTIVATE;	/* Return with the page locked */
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
944
945
946
  }
  
  #ifdef CONFIG_NUMA
d15c023b4   Hugh Dickins   [PATCH] shmem: in...
947
  static inline int shmem_parse_mpol(char *value, int *policy, nodemask_t *policy_nodes)
b00dc3ad7   Hugh Dickins   [PATCH] tmpfs: fi...
948
949
950
951
952
953
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955
956
957
958
959
960
961
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979
980
981
982
983
984
985
986
987
988
989
990
  {
  	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;
  }
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
991
992
993
994
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996
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1003
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1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
  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 *
6daa0e286   Al Viro   [PATCH] gfp_t: mm...
1028
  shmem_alloc_page(gfp_t gfp, struct shmem_inode_info *info,
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
  		 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
b00dc3ad7   Hugh Dickins   [PATCH] tmpfs: fi...
1043
1044
1045
1046
  static inline int shmem_parse_mpol(char *value, int *policy, nodemask_t *policy_nodes)
  {
  	return 1;
  }
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1047
1048
1049
1050
1051
1052
1053
1054
  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 *
dd0fc66fb   Al Viro   [PATCH] gfp flags...
1055
  shmem_alloc_page(gfp_t gfp,struct shmem_inode_info *info, unsigned long idx)
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
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1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
  {
  	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);
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1114
1115
  			/* here we actually do the io */
  			if (type && *type == VM_FAULT_MINOR) {
f8891e5e1   Christoph Lameter   [PATCH] Light wei...
1116
  				__count_vm_event(PGMAJFAULT);
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1117
1118
  				*type = VM_FAULT_MAJOR;
  			}
f8891e5e1   Christoph Lameter   [PATCH] Light wei...
1119
  			spin_unlock(&info->lock);
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1120
1121
1122
1123
1124
1125
1126
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1129
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1183
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1186
1187
1188
1189
1190
1191
1192
  			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 */
3fcfab16c   Andrew Morton   [PATCH] separate ...
1193
  				congestion_wait(WRITE, HZ/50);
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
  			}
  			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);
0edd73b33   Hugh Dickins   [PATCH] shmem: re...
1212
  		if (sbinfo->max_blocks) {
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1213
1214
1215
1216
1217
1218
1219
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  			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;
  }
9b83a6a85   Adrian Bunk   [PATCH] mm/{,tiny...
1283
1284
  static struct page *shmem_nopage(struct vm_area_struct *vma,
  				 unsigned long address, int *type)
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1285
  {
d3ac7f892   Josef "Jeff" Sipek   [PATCH] mm: chang...
1286
  	struct inode *inode = vma->vm_file->f_path.dentry->d_inode;
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1287
1288
1289
1290
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1300
1301
1302
1303
1304
1305
1306
1307
1308
  	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)
  {
d3ac7f892   Josef "Jeff" Sipek   [PATCH] mm: chang...
1309
  	struct inode *inode = vma->vm_file->f_path.dentry->d_inode;
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
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1324
1325
1326
  	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;
d44ed4f86   Paolo 'Blaisorblade' Giarrusso   [PATCH] shmem_pop...
1327
  		/* Page may still be null, but only if nonblock was set. */
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1328
1329
1330
1331
1332
1333
1334
  		if (page) {
  			mark_page_accessed(page);
  			err = install_page(mm, vma, addr, page, prot);
  			if (err) {
  				page_cache_release(page);
  				return err;
  			}
65500d234   Hugh Dickins   [PATCH] mm: page ...
1335
  		} else if (vma->vm_flags & VM_NONLINEAR) {
d44ed4f86   Paolo 'Blaisorblade' Giarrusso   [PATCH] shmem_pop...
1336
1337
1338
  			/* 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. */
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
      			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)
  {
d3ac7f892   Josef "Jeff" Sipek   [PATCH] mm: chang...
1354
  	struct inode *i = vma->vm_file->f_path.dentry->d_inode;
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1355
1356
1357
1358
1359
1360
  	return mpol_set_shared_policy(&SHMEM_I(i)->policy, vma, new);
  }
  
  struct mempolicy *
  shmem_get_policy(struct vm_area_struct *vma, unsigned long addr)
  {
d3ac7f892   Josef "Jeff" Sipek   [PATCH] mm: chang...
1361
  	struct inode *i = vma->vm_file->f_path.dentry->d_inode;
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1362
1363
1364
1365
1366
1367
1368
1369
1370
  	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)
  {
d3ac7f892   Josef "Jeff" Sipek   [PATCH] mm: chang...
1371
  	struct inode *inode = file->f_path.dentry->d_inode;
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
  	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;
  }
9b83a6a85   Adrian Bunk   [PATCH] mm/{,tiny...
1390
  static int shmem_mmap(struct file *file, struct vm_area_struct *vma)
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
  {
  	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);
0edd73b33   Hugh Dickins   [PATCH] shmem: re...
1403
  	if (sbinfo->max_inodes) {
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
  		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;
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1418
1419
1420
1421
  		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;
91828a405   David M. Grimes   [PATCH] knfsd: ad...
1422
  		inode->i_generation = get_seconds();
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1423
1424
1425
1426
1427
1428
1429
  		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:
39f0247d3   Andreas Gruenbacher   [PATCH] Access Co...
1430
  			inode->i_op = &shmem_special_inode_operations;
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1431
1432
1433
1434
1435
  			init_special_inode(inode, mode, dev);
  			break;
  		case S_IFREG:
  			inode->i_op = &shmem_inode_operations;
  			inode->i_fop = &shmem_file_operations;
7339ff830   Robin Holt   [PATCH] Add tmpfs...
1436
1437
  			mpol_shared_policy_init(&info->policy, sbinfo->policy,
  							&sbinfo->policy_nodes);
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1438
1439
  			break;
  		case S_IFDIR:
d8c76e6f4   Dave Hansen   [PATCH] r/o bind ...
1440
  			inc_nlink(inode);
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
  			/* 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.
  			 */
7339ff830   Robin Holt   [PATCH] Add tmpfs...
1451
1452
  			mpol_shared_policy_init(&info->policy, MPOL_DEFAULT,
  						NULL);
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1453
1454
  			break;
  		}
0edd73b33   Hugh Dickins   [PATCH] shmem: re...
1455
  	} else if (sbinfo->max_inodes) {
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1456
1457
1458
1459
1460
1461
1462
1463
  		spin_lock(&sbinfo->stat_lock);
  		sbinfo->free_inodes++;
  		spin_unlock(&sbinfo->stat_lock);
  	}
  	return inode;
  }
  
  #ifdef CONFIG_TMPFS
92e1d5be9   Arjan van de Ven   [PATCH] mark stru...
1464
1465
  static const struct inode_operations shmem_symlink_inode_operations;
  static const struct inode_operations shmem_symlink_inline_operations;
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
  
  /*
   * 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)
  {
d3ac7f892   Josef "Jeff" Sipek   [PATCH] mm: chang...
1481
  	struct inode	*inode = file->f_path.dentry->d_inode;
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1482
1483
1484
1485
1486
1487
1488
1489
1490
  	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;
1b1dcc1b5   Jes Sorensen   [PATCH] mutex sub...
1491
  	mutex_lock(&inode->i_mutex);
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1492
1493
1494
1495
1496
1497
1498
  
  	pos = *ppos;
  	written = 0;
  
  	err = generic_write_checks(file, &pos, &count, 0);
  	if (err || !count)
  		goto out;
d3ac7f892   Josef "Jeff" Sipek   [PATCH] mm: chang...
1499
  	err = remove_suid(file->f_path.dentry);
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
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1513
1514
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1523
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1534
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1536
1537
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1557
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1561
1562
1563
1564
1565
1566
1567
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1569
1570
1571
1572
1573
1574
  	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:
1b1dcc1b5   Jes Sorensen   [PATCH] mutex sub...
1575
  	mutex_unlock(&inode->i_mutex);
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1576
1577
1578
1579
1580
  	return err;
  }
  
  static void do_shmem_file_read(struct file *filp, loff_t *ppos, read_descriptor_t *desc, read_actor_t actor)
  {
d3ac7f892   Josef "Jeff" Sipek   [PATCH] mm: chang...
1581
  	struct inode *inode = filp->f_path.dentry->d_inode;
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
  	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)
1b1dcc1b5   Jes Sorensen   [PATCH] mutex sub...
1611
  		 * are called without i_mutex protection against truncate
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
  		 */
  		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);
b5810039a   Nick Piggin   [PATCH] core remo...
1639
  		} else {
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1640
  			page = ZERO_PAGE(0);
b5810039a   Nick Piggin   [PATCH] core remo...
1641
1642
  			page_cache_get(page);
  		}
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
  
  		/*
  		 * 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;
  }
726c33422   David Howells   [PATCH] VFS: Perm...
1710
  static int shmem_statfs(struct dentry *dentry, struct kstatfs *buf)
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1711
  {
726c33422   David Howells   [PATCH] VFS: Perm...
1712
  	struct shmem_sb_info *sbinfo = SHMEM_SB(dentry->d_sb);
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1713
1714
1715
1716
  
  	buf->f_type = TMPFS_MAGIC;
  	buf->f_bsize = PAGE_CACHE_SIZE;
  	buf->f_namelen = NAME_MAX;
0edd73b33   Hugh Dickins   [PATCH] shmem: re...
1717
1718
  	spin_lock(&sbinfo->stat_lock);
  	if (sbinfo->max_blocks) {
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1719
1720
  		buf->f_blocks = sbinfo->max_blocks;
  		buf->f_bavail = buf->f_bfree = sbinfo->free_blocks;
0edd73b33   Hugh Dickins   [PATCH] shmem: re...
1721
1722
  	}
  	if (sbinfo->max_inodes) {
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1723
1724
  		buf->f_files = sbinfo->max_inodes;
  		buf->f_ffree = sbinfo->free_inodes;
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1725
1726
  	}
  	/* else leave those fields 0 like simple_statfs */
0edd73b33   Hugh Dickins   [PATCH] shmem: re...
1727
  	spin_unlock(&sbinfo->stat_lock);
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
  	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) {
570bc1c2e   Stephen Smalley   [PATCH] tmpfs: En...
1741
1742
1743
1744
1745
1746
1747
  		error = security_inode_init_security(inode, dir, NULL, NULL,
  						     NULL);
  		if (error) {
  			if (error != -EOPNOTSUPP) {
  				iput(inode);
  				return error;
  			}
39f0247d3   Andreas Gruenbacher   [PATCH] Access Co...
1748
1749
1750
1751
1752
  		}
  		error = shmem_acl_init(inode, dir);
  		if (error) {
  			iput(inode);
  			return error;
570bc1c2e   Stephen Smalley   [PATCH] tmpfs: En...
1753
  		}
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1754
1755
1756
1757
1758
1759
1760
1761
1762
  		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 */
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
  	}
  	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;
d8c76e6f4   Dave Hansen   [PATCH] r/o bind ...
1773
  	inc_nlink(dir);
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
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1795
  	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.
  	 */
0edd73b33   Hugh Dickins   [PATCH] shmem: re...
1796
  	if (sbinfo->max_inodes) {
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1797
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  		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;
d8c76e6f4   Dave Hansen   [PATCH] r/o bind ...
1808
  	inc_nlink(inode);
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1809
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  	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);
0edd73b33   Hugh Dickins   [PATCH] shmem: re...
1821
  		if (sbinfo->max_inodes) {
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1822
1823
1824
1825
1826
1827
1828
1829
  			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;
9a53c3a78   Dave Hansen   [PATCH] r/o bind ...
1830
  	drop_nlink(inode);
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1831
1832
1833
1834
1835
1836
1837
1838
  	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;
9a53c3a78   Dave Hansen   [PATCH] r/o bind ...
1839
1840
  	drop_nlink(dentry->d_inode);
  	drop_nlink(dir);
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1841
1842
1843
1844
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1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
  	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)
9a53c3a78   Dave Hansen   [PATCH] r/o bind ...
1861
  			drop_nlink(old_dir);
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1862
  	} else if (they_are_dirs) {
9a53c3a78   Dave Hansen   [PATCH] r/o bind ...
1863
  		drop_nlink(old_dir);
d8c76e6f4   Dave Hansen   [PATCH] r/o bind ...
1864
  		inc_nlink(new_dir);
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
  	}
  
  	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;
570bc1c2e   Stephen Smalley   [PATCH] tmpfs: En...
1891
1892
1893
1894
1895
1896
1897
1898
1899
  	error = security_inode_init_security(inode, dir, NULL, NULL,
  					     NULL);
  	if (error) {
  		if (error != -EOPNOTSUPP) {
  			iput(inode);
  			return error;
  		}
  		error = 0;
  	}
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
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1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
  	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;
  }
cc314eef0   Linus Torvalds   Fix nasty ncpfs s...
1927
  static void *shmem_follow_link_inline(struct dentry *dentry, struct nameidata *nd)
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1928
1929
  {
  	nd_set_link(nd, (char *)SHMEM_I(dentry->d_inode));
cc314eef0   Linus Torvalds   Fix nasty ncpfs s...
1930
  	return NULL;
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1931
  }
cc314eef0   Linus Torvalds   Fix nasty ncpfs s...
1932
  static void *shmem_follow_link(struct dentry *dentry, struct nameidata *nd)
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1933
1934
1935
1936
  {
  	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));
cc314eef0   Linus Torvalds   Fix nasty ncpfs s...
1937
  	return page;
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1938
  }
cc314eef0   Linus Torvalds   Fix nasty ncpfs s...
1939
  static void shmem_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie)
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1940
1941
  {
  	if (!IS_ERR(nd_get_link(nd))) {
cc314eef0   Linus Torvalds   Fix nasty ncpfs s...
1942
  		struct page *page = cookie;
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1943
1944
1945
  		kunmap(page);
  		mark_page_accessed(page);
  		page_cache_release(page);
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1946
1947
  	}
  }
92e1d5be9   Arjan van de Ven   [PATCH] mark stru...
1948
  static const struct inode_operations shmem_symlink_inline_operations = {
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1949
1950
  	.readlink	= generic_readlink,
  	.follow_link	= shmem_follow_link_inline,
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1951
  };
92e1d5be9   Arjan van de Ven   [PATCH] mark stru...
1952
  static const struct inode_operations shmem_symlink_inode_operations = {
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1953
1954
1955
1956
  	.truncate	= shmem_truncate,
  	.readlink	= generic_readlink,
  	.follow_link	= shmem_follow_link,
  	.put_link	= shmem_put_link,
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1957
  };
39f0247d3   Andreas Gruenbacher   [PATCH] Access Co...
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
  #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);
  }
1f370a23f   Adrian Bunk   [PATCH] make mm/s...
1989
  static struct xattr_handler shmem_xattr_security_handler = {
39f0247d3   Andreas Gruenbacher   [PATCH] Access Co...
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
  	.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
91828a405   David M. Grimes   [PATCH] knfsd: ad...
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
  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,
  };
7339ff830   Robin Holt   [PATCH] Add tmpfs...
2081
2082
2083
  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)
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
2084
2085
  {
  	char *this_char, *value, *rest;
b00dc3ad7   Hugh Dickins   [PATCH] tmpfs: fi...
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
  	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;
  			}
  		}
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
  		if (!*this_char)
  			continue;
  		if ((value = strchr(this_char,'=')) != NULL) {
  			*value++ = 0;
  		} else {
  			printk(KERN_ERR
  			    "tmpfs: No value for mount option '%s'
  ",
  			    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;
7339ff830   Robin Holt   [PATCH] Add tmpfs...
2153
  		} else if (!strcmp(this_char,"mpol")) {
b00dc3ad7   Hugh Dickins   [PATCH] tmpfs: fi...
2154
  			if (shmem_parse_mpol(value,policy,policy_nodes))
7339ff830   Robin Holt   [PATCH] Add tmpfs...
2155
  				goto bad_val;
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
  		} else {
  			printk(KERN_ERR "tmpfs: Bad mount option %s
  ",
  			       this_char);
  			return 1;
  		}
  	}
  	return 0;
  
  bad_val:
  	printk(KERN_ERR "tmpfs: Bad value '%s' for mount option '%s'
  ",
  	       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);
0edd73b33   Hugh Dickins   [PATCH] shmem: re...
2176
2177
  	unsigned long max_blocks = sbinfo->max_blocks;
  	unsigned long max_inodes = sbinfo->max_inodes;
7339ff830   Robin Holt   [PATCH] Add tmpfs...
2178
2179
  	int policy = sbinfo->policy;
  	nodemask_t policy_nodes = sbinfo->policy_nodes;
0edd73b33   Hugh Dickins   [PATCH] shmem: re...
2180
2181
2182
  	unsigned long blocks;
  	unsigned long inodes;
  	int error = -EINVAL;
7339ff830   Robin Holt   [PATCH] Add tmpfs...
2183
2184
  	if (shmem_parse_options(data, NULL, NULL, NULL, &max_blocks,
  				&max_inodes, &policy, &policy_nodes))
0edd73b33   Hugh Dickins   [PATCH] shmem: re...
2185
  		return error;
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
2186

0edd73b33   Hugh Dickins   [PATCH] shmem: re...
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
  	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;
7339ff830   Robin Holt   [PATCH] Add tmpfs...
2210
2211
  	sbinfo->policy = policy;
  	sbinfo->policy_nodes = policy_nodes;
0edd73b33   Hugh Dickins   [PATCH] shmem: re...
2212
2213
2214
  out:
  	spin_unlock(&sbinfo->stat_lock);
  	return error;
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
2215
2216
2217
2218
2219
2220
2221
2222
  }
  #endif
  
  static void shmem_put_super(struct super_block *sb)
  {
  	kfree(sb->s_fs_info);
  	sb->s_fs_info = NULL;
  }
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
2223
2224
2225
2226
2227
2228
2229
2230
2231
  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;
0edd73b33   Hugh Dickins   [PATCH] shmem: re...
2232
  	struct shmem_sb_info *sbinfo;
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
2233
2234
  	unsigned long blocks = 0;
  	unsigned long inodes = 0;
7339ff830   Robin Holt   [PATCH] Add tmpfs...
2235
2236
  	int policy = MPOL_DEFAULT;
  	nodemask_t policy_nodes = node_online_map;
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
2237

0edd73b33   Hugh Dickins   [PATCH] shmem: re...
2238
  #ifdef CONFIG_TMPFS
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
  	/*
  	 * 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;
7339ff830   Robin Holt   [PATCH] Add tmpfs...
2249
2250
  		if (shmem_parse_options(data, &mode, &uid, &gid, &blocks,
  					&inodes, &policy, &policy_nodes))
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
2251
2252
  			return -EINVAL;
  	}
91828a405   David M. Grimes   [PATCH] knfsd: ad...
2253
  	sb->s_export_op = &shmem_export_ops;
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
2254
2255
2256
  #else
  	sb->s_flags |= MS_NOUSER;
  #endif
0edd73b33   Hugh Dickins   [PATCH] shmem: re...
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
  	/* 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;
7339ff830   Robin Holt   [PATCH] Add tmpfs...
2268
2269
  	sbinfo->policy = policy;
  	sbinfo->policy_nodes = policy_nodes;
0edd73b33   Hugh Dickins   [PATCH] shmem: re...
2270
2271
  
  	sb->s_fs_info = sbinfo;
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
2272
2273
2274
2275
2276
  	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;
cfd95a9cf   Robin H. Johnson   [PATCH] tmpfs: ti...
2277
  	sb->s_time_gran = 1;
39f0247d3   Andreas Gruenbacher   [PATCH] Access Co...
2278
2279
2280
2281
  #ifdef CONFIG_TMPFS_POSIX_ACL
  	sb->s_xattr = shmem_xattr_handlers;
  	sb->s_flags |= MS_POSIXACL;
  #endif
0edd73b33   Hugh Dickins   [PATCH] shmem: re...
2282

1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
2283
2284
2285
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2288
2289
2290
2291
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2294
2295
2296
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2298
2299
  	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;
  }
fcc234f88   Pekka Enberg   [PATCH] mm: kill ...
2300
  static struct kmem_cache *shmem_inode_cachep;
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
2301
2302
2303
2304
  
  static struct inode *shmem_alloc_inode(struct super_block *sb)
  {
  	struct shmem_inode_info *p;
e94b17660   Christoph Lameter   [PATCH] slab: rem...
2305
  	p = (struct shmem_inode_info *)kmem_cache_alloc(shmem_inode_cachep, GFP_KERNEL);
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
  	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);
  	}
39f0247d3   Andreas Gruenbacher   [PATCH] Access Co...
2317
  	shmem_acl_destroy_inode(inode);
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
2318
2319
  	kmem_cache_free(shmem_inode_cachep, SHMEM_I(inode));
  }
fcc234f88   Pekka Enberg   [PATCH] mm: kill ...
2320
2321
  static void init_once(void *foo, struct kmem_cache *cachep,
  		      unsigned long flags)
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
2322
2323
2324
2325
2326
2327
  {
  	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);
39f0247d3   Andreas Gruenbacher   [PATCH] Access Co...
2328
2329
2330
2331
  #ifdef CONFIG_TMPFS_POSIX_ACL
  		p->i_acl = NULL;
  		p->i_default_acl = NULL;
  #endif
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
2332
2333
2334
2335
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2337
2338
2339
2340
2341
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2343
2344
2345
2346
  	}
  }
  
  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)
  {
1a1d92c10   Alexey Dobriyan   [PATCH] Really ig...
2347
  	kmem_cache_destroy(shmem_inode_cachep);
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
2348
  }
f5e54d6e5   Christoph Hellwig   [PATCH] mark addr...
2349
  static const struct address_space_operations shmem_aops = {
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
2350
  	.writepage	= shmem_writepage,
767193253   Ken Chen   [PATCH] simplify ...
2351
  	.set_page_dirty	= __set_page_dirty_no_writeback,
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
2352
2353
2354
2355
  #ifdef CONFIG_TMPFS
  	.prepare_write	= shmem_prepare_write,
  	.commit_write	= simple_commit_write,
  #endif
304dbdb7a   Lee Schermerhorn   [PATCH] add migra...
2356
  	.migratepage	= migrate_page,
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
2357
  };
15ad7cdcf   Helge Deller   [PATCH] struct se...
2358
  static const struct file_operations shmem_file_operations = {
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
2359
2360
2361
2362
2363
2364
2365
2366
2367
  	.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
  };
92e1d5be9   Arjan van de Ven   [PATCH] mark stru...
2368
  static const struct inode_operations shmem_inode_operations = {
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
2369
2370
  	.truncate	= shmem_truncate,
  	.setattr	= shmem_notify_change,
f6b3ec238   Badari Pulavarty   [PATCH] madvise(M...
2371
  	.truncate_range	= shmem_truncate_range,
39f0247d3   Andreas Gruenbacher   [PATCH] Access Co...
2372
2373
2374
2375
2376
2377
2378
  #ifdef CONFIG_TMPFS_POSIX_ACL
  	.setxattr	= generic_setxattr,
  	.getxattr	= generic_getxattr,
  	.listxattr	= generic_listxattr,
  	.removexattr	= generic_removexattr,
  	.permission	= shmem_permission,
  #endif
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
2379
  };
92e1d5be9   Arjan van de Ven   [PATCH] mark stru...
2380
  static const struct inode_operations shmem_dir_inode_operations = {
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
  #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,
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
2391
  #endif
39f0247d3   Andreas Gruenbacher   [PATCH] Access Co...
2392
2393
2394
2395
2396
2397
2398
2399
2400
  #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
  };
92e1d5be9   Arjan van de Ven   [PATCH] mark stru...
2401
  static const struct inode_operations shmem_special_inode_operations = {
39f0247d3   Andreas Gruenbacher   [PATCH] Access Co...
2402
2403
2404
2405
2406
2407
2408
2409
  #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
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
2410
  };
759b9775c   Hugh Dickins   [PATCH] shmem and...
2411
  static const struct super_operations shmem_ops = {
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
  	.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
  };
454e2398b   David Howells   [PATCH] VFS: Perm...
2431
2432
  static int shmem_get_sb(struct file_system_type *fs_type,
  	int flags, const char *dev_name, void *data, struct vfsmount *mnt)
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
2433
  {
454e2398b   David Howells   [PATCH] VFS: Perm...
2434
  	return get_sb_nodev(fs_type, flags, data, shmem_fill_super, mnt);
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
  }
  
  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
  ");
  		goto out2;
  	}
95dc112a5   Greg Kroah-Hartman   [PATCH] devfs: Re...
2459

1f5ce9e93   Trond Myklebust   VFS: Unexport do_...
2460
  	shm_mnt = vfs_kern_mount(&tmpfs_fs_type, MS_NOUSER,
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
2461
2462
2463
2464
2465
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2468
2469
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2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
  				tmpfs_fs_type.name, NULL);
  	if (IS_ERR(shm_mnt)) {
  		error = PTR_ERR(shm_mnt);
  		printk(KERN_ERR "Could not kern_mount tmpfs
  ");
  		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 */
d3ac7f892   Josef "Jeff" Sipek   [PATCH] mm: chang...
2527
2528
  	file->f_path.mnt = mntget(shm_mnt);
  	file->f_path.dentry = dentry;
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
2529
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2562
  	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;
  }