aboutsummaryrefslogtreecommitdiffstats
path: root/mm/shmem.c
diff options
context:
space:
mode:
Diffstat (limited to 'mm/shmem.c')
-rw-r--r--mm/shmem.c1493
1 files changed, 490 insertions, 1003 deletions
diff --git a/mm/shmem.c b/mm/shmem.c
index 5cc21f8b4cd3..32f6763f16fb 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -6,7 +6,8 @@
* 2000-2001 Christoph Rohland
* 2000-2001 SAP AG
* 2002 Red Hat Inc.
- * Copyright (C) 2002-2005 Hugh Dickins.
+ * Copyright (C) 2002-2011 Hugh Dickins.
+ * Copyright (C) 2011 Google Inc.
* Copyright (C) 2002-2005 VERITAS Software Corporation.
* Copyright (C) 2004 Andi Kleen, SuSE Labs
*
@@ -28,7 +29,6 @@
#include <linux/file.h>
#include <linux/mm.h>
#include <linux/module.h>
-#include <linux/percpu_counter.h>
#include <linux/swap.h>
static struct vfsmount *shm_mnt;
@@ -51,6 +51,8 @@ static struct vfsmount *shm_mnt;
#include <linux/shmem_fs.h>
#include <linux/writeback.h>
#include <linux/blkdev.h>
+#include <linux/pagevec.h>
+#include <linux/percpu_counter.h>
#include <linux/splice.h>
#include <linux/security.h>
#include <linux/swapops.h>
@@ -63,43 +65,17 @@ static struct vfsmount *shm_mnt;
#include <linux/magic.h>
#include <asm/uaccess.h>
-#include <asm/div64.h>
#include <asm/pgtable.h>
-/*
- * The maximum size of a shmem/tmpfs file is limited by the maximum size of
- * its triple-indirect swap vector - see illustration at shmem_swp_entry().
- *
- * With 4kB page size, maximum file size is just over 2TB on a 32-bit kernel,
- * but one eighth of that on a 64-bit kernel. With 8kB page size, maximum
- * file size is just over 4TB on a 64-bit kernel, but 16TB on a 32-bit kernel,
- * MAX_LFS_FILESIZE being then more restrictive than swap vector layout.
- *
- * We use / and * instead of shifts in the definitions below, so that the swap
- * vector can be tested with small even values (e.g. 20) for ENTRIES_PER_PAGE.
- */
-#define ENTRIES_PER_PAGE (PAGE_CACHE_SIZE/sizeof(unsigned long))
-#define ENTRIES_PER_PAGEPAGE ((unsigned long long)ENTRIES_PER_PAGE*ENTRIES_PER_PAGE)
-
-#define SHMSWP_MAX_INDEX (SHMEM_NR_DIRECT + (ENTRIES_PER_PAGEPAGE/2) * (ENTRIES_PER_PAGE+1))
-#define SHMSWP_MAX_BYTES (SHMSWP_MAX_INDEX << PAGE_CACHE_SHIFT)
-
-#define SHMEM_MAX_BYTES min_t(unsigned long long, SHMSWP_MAX_BYTES, MAX_LFS_FILESIZE)
-#define SHMEM_MAX_INDEX ((unsigned long)((SHMEM_MAX_BYTES+1) >> PAGE_CACHE_SHIFT))
-
#define BLOCKS_PER_PAGE (PAGE_CACHE_SIZE/512)
#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
+/* Symlink up to this size is kmalloc'ed instead of using a swappable page */
+#define SHORT_SYMLINK_LEN 128
+
struct shmem_xattr {
struct list_head list; /* anchored by shmem_inode_info->xattr_list */
char *name; /* xattr name */
@@ -107,7 +83,7 @@ struct shmem_xattr {
char value[0];
};
-/* Flag allocation requirements to shmem_getpage and shmem_swp_alloc */
+/* Flag allocation requirements to shmem_getpage */
enum sgp_type {
SGP_READ, /* don't exceed i_size, don't allocate page */
SGP_CACHE, /* don't exceed i_size, may allocate page */
@@ -137,56 +113,6 @@ static inline int shmem_getpage(struct inode *inode, pgoff_t index,
mapping_gfp_mask(inode->i_mapping), fault_type);
}
-static inline struct page *shmem_dir_alloc(gfp_t gfp_mask)
-{
- /*
- * The above definition of ENTRIES_PER_PAGE, and the use of
- * BLOCKS_PER_PAGE on indirect pages, assume PAGE_CACHE_SIZE:
- * might be reconsidered if it ever diverges from PAGE_SIZE.
- *
- * Mobility flags are masked out as swap vectors cannot move
- */
- return alloc_pages((gfp_mask & ~GFP_MOVABLE_MASK) | __GFP_ZERO,
- 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;
@@ -244,15 +170,6 @@ static struct backing_dev_info shmem_backing_dev_info __read_mostly = {
static LIST_HEAD(shmem_swaplist);
static DEFINE_MUTEX(shmem_swaplist_mutex);
-static void shmem_free_blocks(struct inode *inode, long pages)
-{
- struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
- if (sbinfo->max_blocks) {
- percpu_counter_add(&sbinfo->used_blocks, -pages);
- inode->i_blocks -= pages*BLOCKS_PER_PAGE;
- }
-}
-
static int shmem_reserve_inode(struct super_block *sb)
{
struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
@@ -279,7 +196,7 @@ static void shmem_free_inode(struct super_block *sb)
}
/**
- * shmem_recalc_inode - recalculate the size of an inode
+ * shmem_recalc_inode - recalculate the block usage of an inode
* @inode: inode to recalc
*
* We have to calculate the free blocks since the mm can drop
@@ -297,474 +214,297 @@ static void shmem_recalc_inode(struct inode *inode)
freed = info->alloced - info->swapped - inode->i_mapping->nrpages;
if (freed > 0) {
+ struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
+ if (sbinfo->max_blocks)
+ percpu_counter_add(&sbinfo->used_blocks, -freed);
info->alloced -= freed;
+ inode->i_blocks -= freed * BLOCKS_PER_PAGE;
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
+/*
+ * Replace item expected in radix tree by a new item, while holding tree lock.
*/
-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);
- }
+static int shmem_radix_tree_replace(struct address_space *mapping,
+ pgoff_t index, void *expected, void *replacement)
+{
+ void **pslot;
+ void *item = NULL;
+
+ VM_BUG_ON(!expected);
+ pslot = radix_tree_lookup_slot(&mapping->page_tree, index);
+ if (pslot)
+ item = radix_tree_deref_slot_protected(pslot,
+ &mapping->tree_lock);
+ if (item != expected)
+ return -ENOENT;
+ if (replacement)
+ radix_tree_replace_slot(pslot, replacement);
+ else
+ radix_tree_delete(&mapping->page_tree, index);
+ return 0;
+}
- dir += index;
- subdir = *dir;
- if (!subdir) {
- if (!page || !(subdir = *page)) {
- shmem_dir_unmap(dir);
- return NULL; /* need a page */
+/*
+ * Like add_to_page_cache_locked, but error if expected item has gone.
+ */
+static int shmem_add_to_page_cache(struct page *page,
+ struct address_space *mapping,
+ pgoff_t index, gfp_t gfp, void *expected)
+{
+ int error = 0;
+
+ VM_BUG_ON(!PageLocked(page));
+ VM_BUG_ON(!PageSwapBacked(page));
+
+ if (!expected)
+ error = radix_tree_preload(gfp & GFP_RECLAIM_MASK);
+ if (!error) {
+ page_cache_get(page);
+ page->mapping = mapping;
+ page->index = index;
+
+ spin_lock_irq(&mapping->tree_lock);
+ if (!expected)
+ error = radix_tree_insert(&mapping->page_tree,
+ index, page);
+ else
+ error = shmem_radix_tree_replace(mapping, index,
+ expected, page);
+ if (!error) {
+ mapping->nrpages++;
+ __inc_zone_page_state(page, NR_FILE_PAGES);
+ __inc_zone_page_state(page, NR_SHMEM);
+ spin_unlock_irq(&mapping->tree_lock);
+ } else {
+ page->mapping = NULL;
+ spin_unlock_irq(&mapping->tree_lock);
+ page_cache_release(page);
}
- *dir = subdir;
- *page = NULL;
+ if (!expected)
+ radix_tree_preload_end();
}
- shmem_dir_unmap(dir);
- return shmem_swp_map(subdir) + offset;
+ if (error)
+ mem_cgroup_uncharge_cache_page(page);
+ return error;
}
-static void shmem_swp_set(struct shmem_inode_info *info, swp_entry_t *entry, unsigned long value)
+/*
+ * Like delete_from_page_cache, but substitutes swap for page.
+ */
+static void shmem_delete_from_page_cache(struct page *page, void *radswap)
{
- long incdec = value? 1: -1;
+ struct address_space *mapping = page->mapping;
+ int error;
- entry->val = value;
- info->swapped += incdec;
- if ((unsigned long)(entry - info->i_direct) >= SHMEM_NR_DIRECT) {
- struct page *page = kmap_atomic_to_page(entry);
- set_page_private(page, page_private(page) + incdec);
- }
+ spin_lock_irq(&mapping->tree_lock);
+ error = shmem_radix_tree_replace(mapping, page->index, page, radswap);
+ page->mapping = NULL;
+ mapping->nrpages--;
+ __dec_zone_page_state(page, NR_FILE_PAGES);
+ __dec_zone_page_state(page, NR_SHMEM);
+ spin_unlock_irq(&mapping->tree_lock);
+ page_cache_release(page);
+ BUG_ON(error);
}
-/**
- * shmem_swp_alloc - get the position of the swap entry for the page.
- * @info: info structure for the inode
- * @index: index of the page to find
- * @sgp: check and recheck i_size? skip allocation?
- * @gfp: gfp mask to use for any page allocation
- *
- * If the entry does not exist, allocate it.
+/*
+ * Like find_get_pages, but collecting swap entries as well as pages.
*/
-static swp_entry_t *shmem_swp_alloc(struct shmem_inode_info *info,
- unsigned long index, enum sgp_type sgp, gfp_t gfp)
-{
- 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 used_blocks against 1 less max_blocks, since we have 1 data
- * page (and perhaps indirect index pages) yet to allocate:
- * a waste to allocate index if we cannot allocate data.
- */
- if (sbinfo->max_blocks) {
- if (percpu_counter_compare(&sbinfo->used_blocks,
- sbinfo->max_blocks - 1) >= 0)
- return ERR_PTR(-ENOSPC);
- percpu_counter_inc(&sbinfo->used_blocks);
- inode->i_blocks += BLOCKS_PER_PAGE;
+static unsigned shmem_find_get_pages_and_swap(struct address_space *mapping,
+ pgoff_t start, unsigned int nr_pages,
+ struct page **pages, pgoff_t *indices)
+{
+ unsigned int i;
+ unsigned int ret;
+ unsigned int nr_found;
+
+ rcu_read_lock();
+restart:
+ nr_found = radix_tree_gang_lookup_slot(&mapping->page_tree,
+ (void ***)pages, indices, start, nr_pages);
+ ret = 0;
+ for (i = 0; i < nr_found; i++) {
+ struct page *page;
+repeat:
+ page = radix_tree_deref_slot((void **)pages[i]);
+ if (unlikely(!page))
+ continue;
+ if (radix_tree_exception(page)) {
+ if (radix_tree_deref_retry(page))
+ goto restart;
+ /*
+ * Otherwise, we must be storing a swap entry
+ * here as an exceptional entry: so return it
+ * without attempting to raise page count.
+ */
+ goto export;
}
+ if (!page_cache_get_speculative(page))
+ goto repeat;
- spin_unlock(&info->lock);
- page = shmem_dir_alloc(gfp);
- 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;
+ /* Has the page moved? */
+ if (unlikely(page != *((void **)pages[i]))) {
+ page_cache_release(page);
+ goto repeat;
}
- 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;
+export:
+ indices[ret] = indices[i];
+ pages[ret] = page;
+ ret++;
+ }
+ if (unlikely(!ret && nr_found))
+ goto restart;
+ rcu_read_unlock();
+ return ret;
}
-/**
- * shmem_free_swp - free some swap entries in a directory
- * @dir: pointer to the directory
- * @edir: pointer after last entry of the directory
- * @punch_lock: pointer to spinlock when needed for the holepunch case
+/*
+ * Remove swap entry from radix tree, free the swap and its page cache.
*/
-static int shmem_free_swp(swp_entry_t *dir, swp_entry_t *edir,
- spinlock_t *punch_lock)
-{
- spinlock_t *punch_unlock = NULL;
- swp_entry_t *ptr;
- int freed = 0;
-
- for (ptr = dir; ptr < edir; ptr++) {
- if (ptr->val) {
- if (unlikely(punch_lock)) {
- punch_unlock = punch_lock;
- punch_lock = NULL;
- spin_lock(punch_unlock);
- if (!ptr->val)
- continue;
- }
- free_swap_and_cache(*ptr);
- *ptr = (swp_entry_t){0};
- freed++;
- }
- }
- if (punch_unlock)
- spin_unlock(punch_unlock);
- return freed;
-}
-
-static int shmem_map_and_free_swp(struct page *subdir, int offset,
- int limit, struct page ***dir, spinlock_t *punch_lock)
-{
- swp_entry_t *ptr;
- int freed = 0;
-
- ptr = shmem_swp_map(subdir);
- for (; offset < limit; offset += LATENCY_LIMIT) {
- int size = limit - offset;
- if (size > LATENCY_LIMIT)
- size = LATENCY_LIMIT;
- freed += shmem_free_swp(ptr+offset, ptr+offset+size,
- punch_lock);
- if (need_resched()) {
- shmem_swp_unmap(ptr);
- if (*dir) {
- shmem_dir_unmap(*dir);
- *dir = NULL;
- }
- cond_resched();
- ptr = shmem_swp_map(subdir);
- }
- }
- shmem_swp_unmap(ptr);
- return freed;
+static int shmem_free_swap(struct address_space *mapping,
+ pgoff_t index, void *radswap)
+{
+ int error;
+
+ spin_lock_irq(&mapping->tree_lock);
+ error = shmem_radix_tree_replace(mapping, index, radswap, NULL);
+ spin_unlock_irq(&mapping->tree_lock);
+ if (!error)
+ free_swap_and_cache(radix_to_swp_entry(radswap));
+ return error;
}
-static void shmem_free_pages(struct list_head *next)
+/*
+ * Pagevec may contain swap entries, so shuffle up pages before releasing.
+ */
+static void shmem_pagevec_release(struct pagevec *pvec)
{
- 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);
+ int i, j;
+
+ for (i = 0, j = 0; i < pagevec_count(pvec); i++) {
+ struct page *page = pvec->pages[i];
+ if (!radix_tree_exceptional_entry(page))
+ pvec->pages[j++] = page;
+ }
+ pvec->nr = j;
+ pagevec_release(pvec);
}
-void shmem_truncate_range(struct inode *inode, loff_t start, loff_t end)
+/*
+ * Remove range of pages and swap entries from radix tree, and free them.
+ */
+void shmem_truncate_range(struct inode *inode, loff_t lstart, loff_t lend)
{
+ struct address_space *mapping = inode->i_mapping;
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;
+ pgoff_t start = (lstart + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
+ unsigned partial = lstart & (PAGE_CACHE_SIZE - 1);
+ pgoff_t end = (lend >> PAGE_CACHE_SHIFT);
+ struct pagevec pvec;
+ pgoff_t indices[PAGEVEC_SIZE];
long nr_swaps_freed = 0;
- int offset;
- int freed;
- int punch_hole;
- spinlock_t *needs_lock;
- spinlock_t *punch_lock;
- unsigned long upper_limit;
+ pgoff_t index;
+ int i;
- truncate_inode_pages_range(inode->i_mapping, start, end);
+ BUG_ON((lend & (PAGE_CACHE_SIZE - 1)) != (PAGE_CACHE_SIZE - 1));
- inode->i_ctime = inode->i_mtime = CURRENT_TIME;
- idx = (start + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
- if (idx >= info->next_index)
- return;
+ pagevec_init(&pvec, 0);
+ index = start;
+ while (index <= end) {
+ pvec.nr = shmem_find_get_pages_and_swap(mapping, index,
+ min(end - index, (pgoff_t)PAGEVEC_SIZE - 1) + 1,
+ pvec.pages, indices);
+ if (!pvec.nr)
+ break;
+ mem_cgroup_uncharge_start();
+ for (i = 0; i < pagevec_count(&pvec); i++) {
+ struct page *page = pvec.pages[i];
- spin_lock(&info->lock);
- info->flags |= SHMEM_TRUNCATE;
- if (likely(end == (loff_t) -1)) {
- limit = info->next_index;
- upper_limit = SHMEM_MAX_INDEX;
- info->next_index = idx;
- needs_lock = NULL;
- punch_hole = 0;
- } else {
- if (end + 1 >= inode->i_size) { /* we may free a little more */
- limit = (inode->i_size + PAGE_CACHE_SIZE - 1) >>
- PAGE_CACHE_SHIFT;
- upper_limit = SHMEM_MAX_INDEX;
- } else {
- limit = (end + 1) >> PAGE_CACHE_SHIFT;
- upper_limit = limit;
- }
- needs_lock = &info->lock;
- punch_hole = 1;
- }
+ index = indices[i];
+ if (index > end)
+ break;
+
+ if (radix_tree_exceptional_entry(page)) {
+ nr_swaps_freed += !shmem_free_swap(mapping,
+ index, page);
+ continue;
+ }
- topdir = info->i_indirect;
- if (topdir && idx <= SHMEM_NR_DIRECT && !punch_hole) {
- info->i_indirect = NULL;
- nr_pages_to_free++;
- list_add(&topdir->lru, &pages_to_free);
+ if (!trylock_page(page))
+ continue;
+ if (page->mapping == mapping) {
+ VM_BUG_ON(PageWriteback(page));
+ truncate_inode_page(mapping, page);
+ }
+ unlock_page(page);
+ }
+ shmem_pagevec_release(&pvec);
+ mem_cgroup_uncharge_end();
+ cond_resched();
+ index++;
}
- spin_unlock(&info->lock);
- if (info->swapped && idx < SHMEM_NR_DIRECT) {
- ptr = info->i_direct;
- size = limit;
- if (size > SHMEM_NR_DIRECT)
- size = SHMEM_NR_DIRECT;
- nr_swaps_freed = shmem_free_swp(ptr+idx, ptr+size, needs_lock);
+ if (partial) {
+ struct page *page = NULL;
+ shmem_getpage(inode, start - 1, &page, SGP_READ, NULL);
+ if (page) {
+ zero_user_segment(page, partial, PAGE_CACHE_SIZE);
+ set_page_dirty(page);
+ unlock_page(page);
+ page_cache_release(page);
+ }
}
- /*
- * If there are no indirect blocks or we are punching a hole
- * below indirect blocks, nothing to be done.
- */
- if (!topdir || limit <= SHMEM_NR_DIRECT)
- goto done2;
+ index = start;
+ for ( ; ; ) {
+ cond_resched();
+ pvec.nr = shmem_find_get_pages_and_swap(mapping, index,
+ min(end - index, (pgoff_t)PAGEVEC_SIZE - 1) + 1,
+ pvec.pages, indices);
+ if (!pvec.nr) {
+ if (index == start)
+ break;
+ index = start;
+ continue;
+ }
+ if (index == start && indices[0] > end) {
+ shmem_pagevec_release(&pvec);
+ break;
+ }
+ mem_cgroup_uncharge_start();
+ for (i = 0; i < pagevec_count(&pvec); i++) {
+ struct page *page = pvec.pages[i];
- /*
- * 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.
- */
+ index = indices[i];
+ if (index > end)
+ break;
- upper_limit -= SHMEM_NR_DIRECT;
- limit -= SHMEM_NR_DIRECT;
- idx = (idx > SHMEM_NR_DIRECT)? (idx - SHMEM_NR_DIRECT): 0;
- offset = idx % ENTRIES_PER_PAGE;
- idx -= offset;
-
- dir = shmem_dir_map(topdir);
- stage = ENTRIES_PER_PAGEPAGE/2;
- if (idx < ENTRIES_PER_PAGEPAGE/2) {
- middir = topdir;
- diroff = idx/ENTRIES_PER_PAGE;
- } else {
- dir += ENTRIES_PER_PAGE/2;
- dir += (idx - ENTRIES_PER_PAGEPAGE/2)/ENTRIES_PER_PAGEPAGE;
- while (stage <= idx)
- stage += ENTRIES_PER_PAGEPAGE;
- middir = *dir;
- if (*dir) {
- diroff = ((idx - ENTRIES_PER_PAGEPAGE/2) %
- ENTRIES_PER_PAGEPAGE) / ENTRIES_PER_PAGE;
- if (!diroff && !offset && upper_limit >= stage) {
- if (needs_lock) {
- spin_lock(needs_lock);
- *dir = NULL;
- spin_unlock(needs_lock);
- needs_lock = NULL;
- } else
- *dir = NULL;
- nr_pages_to_free++;
- list_add(&middir->lru, &pages_to_free);
+ if (radix_tree_exceptional_entry(page)) {
+ nr_swaps_freed += !shmem_free_swap(mapping,
+ index, page);
+ continue;
}
- 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;
- if (punch_hole)
- needs_lock = &info->lock;
- if (upper_limit >= stage) {
- if (needs_lock) {
- spin_lock(needs_lock);
- *dir = NULL;
- spin_unlock(needs_lock);
- needs_lock = NULL;
- } else
- *dir = NULL;
- nr_pages_to_free++;
- list_add(&middir->lru, &pages_to_free);
+ lock_page(page);
+ if (page->mapping == mapping) {
+ VM_BUG_ON(PageWriteback(page));
+ truncate_inode_page(mapping, page);
}
- shmem_dir_unmap(dir);
- cond_resched();
- dir = shmem_dir_map(middir);
- diroff = 0;
- }
- punch_lock = needs_lock;
- subdir = dir[diroff];
- if (subdir && !offset && upper_limit-idx >= ENTRIES_PER_PAGE) {
- if (needs_lock) {
- spin_lock(needs_lock);
- dir[diroff] = NULL;
- spin_unlock(needs_lock);
- punch_lock = NULL;
- } else
- dir[diroff] = NULL;
- nr_pages_to_free++;
- list_add(&subdir->lru, &pages_to_free);
- }
- if (subdir && page_private(subdir) /* has swap entries */) {
- size = limit - idx;
- if (size > ENTRIES_PER_PAGE)
- size = ENTRIES_PER_PAGE;
- freed = shmem_map_and_free_swp(subdir,
- offset, size, &dir, punch_lock);
- if (!dir)
- dir = shmem_dir_map(middir);
- nr_swaps_freed += freed;
- if (offset || punch_lock) {
- spin_lock(&info->lock);
- set_page_private(subdir,
- page_private(subdir) - freed);
- spin_unlock(&info->lock);
- } else
- BUG_ON(page_private(subdir) != freed);
+ unlock_page(page);
}
- offset = 0;
- }
-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
- * truncate_pagecache or generic_delete_inode did it, before we
- * lowered next_index. Also, though shmem_getpage checks
- * i_size before adding to cache, no recheck after: so fix the
- * narrow window there too.
- */
- truncate_inode_pages_range(inode->i_mapping, start, end);
+ shmem_pagevec_release(&pvec);
+ mem_cgroup_uncharge_end();
+ index++;
}
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);
- }
+ inode->i_ctime = inode->i_mtime = CURRENT_TIME;
}
EXPORT_SYMBOL_GPL(shmem_truncate_range);
@@ -780,37 +520,7 @@ static int shmem_setattr(struct dentry *dentry, struct iattr *attr)
if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) {
loff_t oldsize = inode->i_size;
loff_t newsize = attr->ia_size;
- struct page *page = NULL;
- if (newsize < oldsize) {
- /*
- * 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 cannot miss it were
- * it assigned to swap.
- */
- if (newsize & (PAGE_CACHE_SIZE-1)) {
- (void) shmem_getpage(inode,
- newsize >> PAGE_CACHE_SHIFT,
- &page, SGP_READ, NULL);
- if (page)
- unlock_page(page);
- }
- /*
- * 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 (newsize) {
- struct shmem_inode_info *info = SHMEM_I(inode);
- spin_lock(&info->lock);
- info->flags &= ~SHMEM_PAGEIN;
- spin_unlock(&info->lock);
- }
- }
if (newsize != oldsize) {
i_size_write(inode, newsize);
inode->i_ctime = inode->i_mtime = CURRENT_TIME;
@@ -822,8 +532,6 @@ static int shmem_setattr(struct dentry *dentry, struct iattr *attr)
/* unmap again to remove racily COWed private pages */
unmap_mapping_range(inode->i_mapping, holebegin, 0, 1);
}
- if (page)
- page_cache_release(page);
}
setattr_copy(inode, attr);
@@ -848,7 +556,8 @@ static void shmem_evict_inode(struct inode *inode)
list_del_init(&info->swaplist);
mutex_unlock(&shmem_swaplist_mutex);
}
- }
+ } else
+ kfree(info->symlink);
list_for_each_entry_safe(xattr, nxattr, &info->xattr_list, list) {
kfree(xattr->name);
@@ -859,106 +568,27 @@ static void shmem_evict_inode(struct inode *inode)
end_writeback(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)
+/*
+ * If swap found in inode, free it and move page from swapcache to filecache.
+ */
+static int shmem_unuse_inode(struct shmem_inode_info *info,
+ swp_entry_t swap, struct page *page)
{
- struct address_space *mapping;
- unsigned long idx;
- unsigned long size;
- unsigned long limit;
- unsigned long stage;
- struct page **dir;
- struct page *subdir;
- swp_entry_t *ptr;
- int offset;
+ struct address_space *mapping = info->vfs_inode.i_mapping;
+ void *radswap;
+ pgoff_t index;
int error;
- idx = 0;
- ptr = info->i_direct;
- spin_lock(&info->lock);
- if (!info->swapped) {
- list_del_init(&info->swaplist);
- goto lost2;
- }
- 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);
- if (cond_resched_lock(&info->lock)) {
- /* check it has not been truncated */
- if (limit > info->next_index) {
- limit = info->next_index;
- if (idx >= limit)
- goto lost2;
- }
- }
- dir = shmem_dir_map(info->i_indirect) +
- ENTRIES_PER_PAGE/2 + idx/ENTRIES_PER_PAGEPAGE;
- while (!*dir) {
- dir++;
- idx += ENTRIES_PER_PAGEPAGE;
- if (idx >= limit)
- goto lost1;
- }
- stage = idx + ENTRIES_PER_PAGEPAGE;
- subdir = *dir;
- shmem_dir_unmap(dir);
- dir = shmem_dir_map(subdir);
- }
- subdir = *dir;
- if (subdir && page_private(subdir)) {
- 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);
- shmem_swp_unmap(ptr);
- if (offset >= 0) {
- shmem_dir_unmap(dir);
- ptr = shmem_swp_map(subdir);
- goto found;
- }
- }
- }
-lost1:
- shmem_dir_unmap(dir-1);
-lost2:
- spin_unlock(&info->lock);
- return 0;
-found:
- idx += offset;
- ptr += offset;
+ radswap = swp_to_radix_entry(swap);
+ index = radix_tree_locate_item(&mapping->page_tree, radswap);
+ if (index == -1)
+ return 0;
/*
* Move _head_ to start search for next from here.
* But be careful: shmem_evict_inode checks list_empty without taking
* mutex, and there's an instant in list_move_tail when info->swaplist
- * would appear empty, if it were the only one on shmem_swaplist. We
- * could avoid doing it if inode NULL; or use this minor optimization.
+ * would appear empty, if it were the only one on shmem_swaplist.
*/
if (shmem_swaplist.next != &info->swaplist)
list_move_tail(&shmem_swaplist, &info->swaplist);
@@ -968,29 +598,34 @@ found:
* but also to hold up shmem_evict_inode(): so inode cannot be freed
* beneath us (pagelock doesn't help until the page is in pagecache).
*/
- mapping = info->vfs_inode.i_mapping;
- error = add_to_page_cache_locked(page, mapping, idx, GFP_NOWAIT);
+ error = shmem_add_to_page_cache(page, mapping, index,
+ GFP_NOWAIT, radswap);
/* which does mem_cgroup_uncharge_cache_page on error */
if (error != -ENOMEM) {
+ /*
+ * Truncation and eviction use free_swap_and_cache(), which
+ * only does trylock page: if we raced, best clean up here.
+ */
delete_from_swap_cache(page);
set_page_dirty(page);
- info->flags |= SHMEM_PAGEIN;
- shmem_swp_set(info, ptr, 0);
- swap_free(entry);
+ if (!error) {
+ spin_lock(&info->lock);
+ info->swapped--;
+ spin_unlock(&info->lock);
+ swap_free(swap);
+ }
error = 1; /* not an error, but entry was found */
}
- shmem_swp_unmap(ptr);
- spin_unlock(&info->lock);
return error;
}
/*
- * shmem_unuse() search for an eventually swapped out shmem page.
+ * Search through swapped inodes to find and replace swap by page.
*/
-int shmem_unuse(swp_entry_t entry, struct page *page)
+int shmem_unuse(swp_entry_t swap, struct page *page)
{
- struct list_head *p, *next;
+ struct list_head *this, *next;
struct shmem_inode_info *info;
int found = 0;
int error;
@@ -999,32 +634,25 @@ int shmem_unuse(swp_entry_t entry, struct page *page)
* Charge page using GFP_KERNEL while we can wait, before taking
* the shmem_swaplist_mutex which might hold up shmem_writepage().
* Charged back to the user (not to caller) when swap account is used.
- * add_to_page_cache() will be called with GFP_NOWAIT.
*/
error = mem_cgroup_cache_charge(page, current->mm, GFP_KERNEL);
if (error)
goto out;
- /*
- * Try to preload while we can wait, to not make a habit of
- * draining atomic reserves; but don't latch on to this cpu,
- * it's okay if sometimes we get rescheduled after this.
- */
- error = radix_tree_preload(GFP_KERNEL);
- if (error)
- goto uncharge;
- radix_tree_preload_end();
+ /* No radix_tree_preload: swap entry keeps a place for page in tree */
mutex_lock(&shmem_swaplist_mutex);
- list_for_each_safe(p, next, &shmem_swaplist) {
- info = list_entry(p, struct shmem_inode_info, swaplist);
- found = shmem_unuse_inode(info, entry, page);
+ list_for_each_safe(this, next, &shmem_swaplist) {
+ info = list_entry(this, struct shmem_inode_info, swaplist);
+ if (info->swapped)
+ found = shmem_unuse_inode(info, swap, page);
+ else
+ list_del_init(&info->swaplist);
cond_resched();
if (found)
break;
}
mutex_unlock(&shmem_swaplist_mutex);
-uncharge:
if (!found)
mem_cgroup_uncharge_cache_page(page);
if (found < 0)
@@ -1041,10 +669,10 @@ out:
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;
+ swp_entry_t swap;
+ pgoff_t index;
BUG_ON(!PageLocked(page));
mapping = page->mapping;
@@ -1073,50 +701,32 @@ static int shmem_writepage(struct page *page, struct writeback_control *wbc)
/*
* Add inode to shmem_unuse()'s list of swapped-out inodes,
- * if it's not already there. Do it now because we cannot take
- * mutex while holding spinlock, and must do so before the page
- * is moved to swap cache, when its pagelock no longer protects
+ * if it's not already there. Do it now before the page is
+ * moved to swap cache, when its pagelock no longer protects
* the inode from eviction. But don't unlock the mutex until
- * we've taken the spinlock, because shmem_unuse_inode() will
- * prune a !swapped inode from the swaplist under both locks.
+ * we've incremented swapped, because shmem_unuse_inode() will
+ * prune a !swapped inode from the swaplist under this mutex.
*/
mutex_lock(&shmem_swaplist_mutex);
if (list_empty(&info->swaplist))
list_add_tail(&info->swaplist, &shmem_swaplist);
- spin_lock(&info->lock);
- mutex_unlock(&shmem_swaplist_mutex);
-
- if (index >= info->next_index) {
- BUG_ON(!(info->flags & SHMEM_TRUNCATE));
- goto unlock;
- }
- entry = shmem_swp_entry(info, index, NULL);
- if (entry->val) {
- WARN_ON_ONCE(1); /* Still happens? Tell us about it! */
- free_swap_and_cache(*entry);
- shmem_swp_set(info, entry, 0);
- }
- shmem_recalc_inode(inode);
-
if (add_to_swap_cache(page, swap, GFP_ATOMIC) == 0) {
- delete_from_page_cache(page);
- shmem_swp_set(info, entry, swap.val);
- shmem_swp_unmap(entry);
swap_shmem_alloc(swap);
+ shmem_delete_from_page_cache(page, swp_to_radix_entry(swap));
+
+ spin_lock(&info->lock);
+ info->swapped++;
+ shmem_recalc_inode(inode);
spin_unlock(&info->lock);
+
+ mutex_unlock(&shmem_swaplist_mutex);
BUG_ON(page_mapped(page));
swap_writepage(page, wbc);
return 0;
}
- shmem_swp_unmap(entry);
-unlock:
- spin_unlock(&info->lock);
- /*
- * add_to_swap_cache() doesn't return -EEXIST, so we can safely
- * clear SWAP_HAS_CACHE flag.
- */
+ mutex_unlock(&shmem_swaplist_mutex);
swapcache_free(swap, NULL);
redirty:
set_page_dirty(page);
@@ -1153,35 +763,33 @@ static struct mempolicy *shmem_get_sbmpol(struct shmem_sb_info *sbinfo)
}
#endif /* CONFIG_TMPFS */
-static struct page *shmem_swapin(swp_entry_t entry, gfp_t gfp,
- struct shmem_inode_info *info, unsigned long idx)
+static struct page *shmem_swapin(swp_entry_t swap, gfp_t gfp,
+ struct shmem_inode_info *info, pgoff_t index)
{
struct mempolicy mpol, *spol;
struct vm_area_struct pvma;
- struct page *page;
spol = mpol_cond_copy(&mpol,
- mpol_shared_policy_lookup(&info->policy, idx));
+ mpol_shared_policy_lookup(&info->policy, index));
/* Create a pseudo vma that just contains the policy */
pvma.vm_start = 0;
- pvma.vm_pgoff = idx;
+ pvma.vm_pgoff = index;
pvma.vm_ops = NULL;
pvma.vm_policy = spol;
- page = swapin_readahead(entry, gfp, &pvma, 0);
- return page;
+ return swapin_readahead(swap, gfp, &pvma, 0);
}
static struct page *shmem_alloc_page(gfp_t gfp,
- struct shmem_inode_info *info, unsigned long idx)
+ struct shmem_inode_info *info, pgoff_t index)
{
struct vm_area_struct pvma;
/* Create a pseudo vma that just contains the policy */
pvma.vm_start = 0;
- pvma.vm_pgoff = idx;
+ pvma.vm_pgoff = index;
pvma.vm_ops = NULL;
- pvma.vm_policy = mpol_shared_policy_lookup(&info->policy, idx);
+ pvma.vm_policy = mpol_shared_policy_lookup(&info->policy, index);
/*
* alloc_page_vma() will drop the shared policy reference
@@ -1190,19 +798,19 @@ static struct page *shmem_alloc_page(gfp_t gfp,
}
#else /* !CONFIG_NUMA */
#ifdef CONFIG_TMPFS
-static inline void shmem_show_mpol(struct seq_file *seq, struct mempolicy *p)
+static inline void shmem_show_mpol(struct seq_file *seq, struct mempolicy *mpol)
{
}
#endif /* CONFIG_TMPFS */
-static inline struct page *shmem_swapin(swp_entry_t entry, gfp_t gfp,
- struct shmem_inode_info *info, unsigned long idx)
+static inline struct page *shmem_swapin(swp_entry_t swap, gfp_t gfp,
+ struct shmem_inode_info *info, pgoff_t index)
{
- return swapin_readahead(entry, gfp, NULL, 0);
+ return swapin_readahead(swap, gfp, NULL, 0);
}
static inline struct page *shmem_alloc_page(gfp_t gfp,
- struct shmem_inode_info *info, unsigned long idx)
+ struct shmem_inode_info *info, pgoff_t index)
{
return alloc_page(gfp);
}
@@ -1222,243 +830,190 @@ static inline struct mempolicy *shmem_get_sbmpol(struct shmem_sb_info *sbinfo)
* 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_gfp(struct inode *inode, pgoff_t idx,
+static int shmem_getpage_gfp(struct inode *inode, pgoff_t index,
struct page **pagep, enum sgp_type sgp, gfp_t gfp, int *fault_type)
{
struct address_space *mapping = inode->i_mapping;
- struct shmem_inode_info *info = SHMEM_I(inode);
+ struct shmem_inode_info *info;
struct shmem_sb_info *sbinfo;
struct page *page;
- struct page *prealloc_page = NULL;
- swp_entry_t *entry;
swp_entry_t swap;
int error;
- int ret;
+ int once = 0;
- if (idx >= SHMEM_MAX_INDEX)
+ if (index > (MAX_LFS_FILESIZE >> PAGE_CACHE_SHIFT))
return -EFBIG;
repeat:
- page = find_lock_page(mapping, idx);
- if (page) {
+ swap.val = 0;
+ page = find_lock_page(mapping, index);
+ if (radix_tree_exceptional_entry(page)) {
+ swap = radix_to_swp_entry(page);
+ page = NULL;
+ }
+
+ if (sgp != SGP_WRITE &&
+ ((loff_t)index << PAGE_CACHE_SHIFT) >= i_size_read(inode)) {
+ error = -EINVAL;
+ goto failed;
+ }
+
+ if (page || (sgp == SGP_READ && !swap.val)) {
/*
* Once we can get the page lock, it must be uptodate:
* if there were an error in reading back from swap,
* the page would not be inserted into the filecache.
*/
- BUG_ON(!PageUptodate(page));
- goto done;
+ BUG_ON(page && !PageUptodate(page));
+ *pagep = page;
+ return 0;
}
/*
- * Try to preload while we can wait, to not make a habit of
- * draining atomic reserves; but don't latch on to this cpu.
+ * Fast cache lookup did not find it:
+ * bring it back from swap or allocate.
*/
- error = radix_tree_preload(gfp & GFP_RECLAIM_MASK);
- if (error)
- goto out;
- radix_tree_preload_end();
-
- if (sgp != SGP_READ && !prealloc_page) {
- prealloc_page = shmem_alloc_page(gfp, info, idx);
- if (prealloc_page) {
- SetPageSwapBacked(prealloc_page);
- if (mem_cgroup_cache_charge(prealloc_page,
- current->mm, GFP_KERNEL)) {
- page_cache_release(prealloc_page);
- prealloc_page = NULL;
- }
- }
- }
-
- spin_lock(&info->lock);
- shmem_recalc_inode(inode);
- entry = shmem_swp_alloc(info, idx, sgp, gfp);
- if (IS_ERR(entry)) {
- spin_unlock(&info->lock);
- error = PTR_ERR(entry);
- goto out;
- }
- swap = *entry;
+ info = SHMEM_I(inode);
+ sbinfo = SHMEM_SB(inode->i_sb);
if (swap.val) {
/* Look it up and read it in.. */
page = lookup_swap_cache(swap);
if (!page) {
- shmem_swp_unmap(entry);
- spin_unlock(&info->lock);
/* here we actually do the io */
if (fault_type)
*fault_type |= VM_FAULT_MAJOR;
- page = shmem_swapin(swap, gfp, info, idx);
+ page = shmem_swapin(swap, gfp, info, index);
if (!page) {
- spin_lock(&info->lock);
- entry = shmem_swp_alloc(info, idx, sgp, gfp);
- 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 out;
- goto repeat;
+ error = -ENOMEM;
+ goto failed;
}
- wait_on_page_locked(page);
- page_cache_release(page);
- goto repeat;
}
/* We have to do this with page locked to prevent races */
- if (!trylock_page(page)) {
- shmem_swp_unmap(entry);
- spin_unlock(&info->lock);
- wait_on_page_locked(page);
- page_cache_release(page);
- goto repeat;
- }
- if (PageWriteback(page)) {
- shmem_swp_unmap(entry);
- spin_unlock(&info->lock);
- wait_on_page_writeback(page);
- unlock_page(page);
- page_cache_release(page);
- goto repeat;
- }
+ lock_page(page);
if (!PageUptodate(page)) {
- shmem_swp_unmap(entry);
- spin_unlock(&info->lock);
- unlock_page(page);
- page_cache_release(page);
error = -EIO;
- goto out;
+ goto failed;
}
-
- error = add_to_page_cache_locked(page, mapping,
- idx, GFP_NOWAIT);
- if (error) {
- shmem_swp_unmap(entry);
- spin_unlock(&info->lock);
- if (error == -ENOMEM) {
- /*
- * reclaim from proper memory cgroup and
- * call memcg's OOM if needed.
- */
- error = mem_cgroup_shmem_charge_fallback(
- page, current->mm, gfp);
- if (error) {
- unlock_page(page);
- page_cache_release(page);
- goto out;
- }
- }
- unlock_page(page);
- page_cache_release(page);
- goto repeat;
+ wait_on_page_writeback(page);
+
+ /* Someone may have already done it for us */
+ if (page->mapping) {
+ if (page->mapping == mapping &&
+ page->index == index)
+ goto done;
+ error = -EEXIST;
+ goto failed;
}
- info->flags |= SHMEM_PAGEIN;
- shmem_swp_set(info, entry, 0);
- shmem_swp_unmap(entry);
- delete_from_swap_cache(page);
+ error = mem_cgroup_cache_charge(page, current->mm,
+ gfp & GFP_RECLAIM_MASK);
+ if (!error)
+ error = shmem_add_to_page_cache(page, mapping, index,
+ gfp, swp_to_radix_entry(swap));
+ if (error)
+ goto failed;
+
+ spin_lock(&info->lock);
+ info->swapped--;
+ shmem_recalc_inode(inode);
spin_unlock(&info->lock);
+
+ delete_from_swap_cache(page);
set_page_dirty(page);
swap_free(swap);
- } else if (sgp == SGP_READ) {
- shmem_swp_unmap(entry);
- page = find_get_page(mapping, idx);
- if (page && !trylock_page(page)) {
- spin_unlock(&info->lock);
- wait_on_page_locked(page);
- page_cache_release(page);
- goto repeat;
+ } else {
+ if (shmem_acct_block(info->flags)) {
+ error = -ENOSPC;
+ goto failed;
}
- spin_unlock(&info->lock);
-
- } else if (prealloc_page) {
- shmem_swp_unmap(entry);
- sbinfo = SHMEM_SB(inode->i_sb);
if (sbinfo->max_blocks) {
if (percpu_counter_compare(&sbinfo->used_blocks,
- sbinfo->max_blocks) >= 0 ||
- shmem_acct_block(info->flags))
- goto nospace;
+ sbinfo->max_blocks) >= 0) {
+ error = -ENOSPC;
+ goto unacct;
+ }
percpu_counter_inc(&sbinfo->used_blocks);
- inode->i_blocks += BLOCKS_PER_PAGE;
- } else if (shmem_acct_block(info->flags))
- goto nospace;
-
- page = prealloc_page;
- prealloc_page = NULL;
-
- entry = shmem_swp_alloc(info, idx, sgp, gfp);
- if (IS_ERR(entry))
- error = PTR_ERR(entry);
- else {
- swap = *entry;
- shmem_swp_unmap(entry);
}
- ret = error || swap.val;
- if (ret)
- mem_cgroup_uncharge_cache_page(page);
- else
- ret = add_to_page_cache_lru(page, mapping,
- idx, GFP_NOWAIT);
- /*
- * At add_to_page_cache_lru() failure,
- * uncharge will be done automatically.
- */
- if (ret) {
- shmem_unacct_blocks(info->flags, 1);
- shmem_free_blocks(inode, 1);
- spin_unlock(&info->lock);
- page_cache_release(page);
- if (error)
- goto out;
- goto repeat;
+
+ page = shmem_alloc_page(gfp, info, index);
+ if (!page) {
+ error = -ENOMEM;
+ goto decused;
}
- info->flags |= SHMEM_PAGEIN;
+ SetPageSwapBacked(page);
+ __set_page_locked(page);
+ error = mem_cgroup_cache_charge(page, current->mm,
+ gfp & GFP_RECLAIM_MASK);
+ if (!error)
+ error = shmem_add_to_page_cache(page, mapping, index,
+ gfp, NULL);
+ if (error)
+ goto decused;
+ lru_cache_add_anon(page);
+
+ spin_lock(&info->lock);
info->alloced++;
+ inode->i_blocks += BLOCKS_PER_PAGE;
+ shmem_recalc_inode(inode);
spin_unlock(&info->lock);
+
clear_highpage(page);
flush_dcache_page(page);
SetPageUptodate(page);
if (sgp == SGP_DIRTY)
set_page_dirty(page);
-
- } else {
- spin_unlock(&info->lock);
- error = -ENOMEM;
- goto out;
}
done:
- *pagep = page;
- error = 0;
-out:
- if (prealloc_page) {
- mem_cgroup_uncharge_cache_page(prealloc_page);
- page_cache_release(prealloc_page);
+ /* Perhaps the file has been truncated since we checked */
+ if (sgp != SGP_WRITE &&
+ ((loff_t)index << PAGE_CACHE_SHIFT) >= i_size_read(inode)) {
+ error = -EINVAL;
+ goto trunc;
}
- return error;
+ *pagep = page;
+ return 0;
-nospace:
/*
- * Perhaps the page was brought in from swap between find_lock_page
- * and taking info->lock? We allow for that at add_to_page_cache_lru,
- * but must also avoid reporting a spurious ENOSPC while working on a
- * full tmpfs.
+ * Error recovery.
*/
- page = find_get_page(mapping, idx);
+trunc:
+ ClearPageDirty(page);
+ delete_from_page_cache(page);
+ spin_lock(&info->lock);
+ info->alloced--;
+ inode->i_blocks -= BLOCKS_PER_PAGE;
spin_unlock(&info->lock);
+decused:
+ if (sbinfo->max_blocks)
+ percpu_counter_add(&sbinfo->used_blocks, -1);
+unacct:
+ shmem_unacct_blocks(info->flags, 1);
+failed:
+ if (swap.val && error != -EINVAL) {
+ struct page *test = find_get_page(mapping, index);
+ if (test && !radix_tree_exceptional_entry(test))
+ page_cache_release(test);
+ /* Have another try if the entry has changed */
+ if (test != swp_to_radix_entry(swap))
+ error = -EEXIST;
+ }
if (page) {
+ unlock_page(page);
page_cache_release(page);
+ }
+ if (error == -ENOSPC && !once++) {
+ info = SHMEM_I(inode);
+ spin_lock(&info->lock);
+ shmem_recalc_inode(inode);
+ spin_unlock(&info->lock);
goto repeat;
}
- error = -ENOSPC;
- goto out;
+ if (error == -EEXIST)
+ goto repeat;
+ return error;
}
static int shmem_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
@@ -1467,9 +1022,6 @@ static int shmem_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
int error;
int ret = VM_FAULT_LOCKED;
- if (((loff_t)vmf->pgoff << PAGE_CACHE_SHIFT) >= i_size_read(inode))
- return VM_FAULT_SIGBUS;
-
error = shmem_getpage(inode, vmf->pgoff, &vmf->page, SGP_CACHE, &ret);
if (error)
return ((error == -ENOMEM) ? VM_FAULT_OOM : VM_FAULT_SIGBUS);
@@ -1482,20 +1034,20 @@ static int shmem_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
}
#ifdef CONFIG_NUMA
-static int shmem_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
+static int shmem_set_policy(struct vm_area_struct *vma, struct mempolicy *mpol)
{
- struct inode *i = vma->vm_file->f_path.dentry->d_inode;
- return mpol_set_shared_policy(&SHMEM_I(i)->policy, vma, new);
+ struct inode *inode = vma->vm_file->f_path.dentry->d_inode;
+ return mpol_set_shared_policy(&SHMEM_I(inode)->policy, vma, mpol);
}
static struct mempolicy *shmem_get_policy(struct vm_area_struct *vma,
unsigned long addr)
{
- struct inode *i = vma->vm_file->f_path.dentry->d_inode;
- unsigned long idx;
+ struct inode *inode = vma->vm_file->f_path.dentry->d_inode;
+ pgoff_t index;
- idx = ((addr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
- return mpol_shared_policy_lookup(&SHMEM_I(i)->policy, idx);
+ index = ((addr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
+ return mpol_shared_policy_lookup(&SHMEM_I(inode)->policy, index);
}
#endif
@@ -1593,7 +1145,7 @@ static struct inode *shmem_get_inode(struct super_block *sb, const struct inode
#ifdef CONFIG_TMPFS
static const struct inode_operations shmem_symlink_inode_operations;
-static const struct inode_operations shmem_symlink_inline_operations;
+static const struct inode_operations shmem_short_symlink_operations;
static int
shmem_write_begin(struct file *file, struct address_space *mapping,
@@ -1626,7 +1178,8 @@ static void do_shmem_file_read(struct file *filp, loff_t *ppos, read_descriptor_
{
struct inode *inode = filp->f_path.dentry->d_inode;
struct address_space *mapping = inode->i_mapping;
- unsigned long index, offset;
+ pgoff_t index;
+ unsigned long offset;
enum sgp_type sgp = SGP_READ;
/*
@@ -1642,7 +1195,8 @@ static void do_shmem_file_read(struct file *filp, loff_t *ppos, read_descriptor_
for (;;) {
struct page *page = NULL;
- unsigned long end_index, nr, ret;
+ pgoff_t end_index;
+ unsigned long nr, ret;
loff_t i_size = i_size_read(inode);
end_index = i_size >> PAGE_CACHE_SHIFT;
@@ -1880,8 +1434,9 @@ static int shmem_statfs(struct dentry *dentry, struct kstatfs *buf)
buf->f_namelen = NAME_MAX;
if (sbinfo->max_blocks) {
buf->f_blocks = sbinfo->max_blocks;
- buf->f_bavail = buf->f_bfree =
- sbinfo->max_blocks - percpu_counter_sum(&sbinfo->used_blocks);
+ buf->f_bavail =
+ buf->f_bfree = sbinfo->max_blocks -
+ percpu_counter_sum(&sbinfo->used_blocks);
}
if (sbinfo->max_inodes) {
buf->f_files = sbinfo->max_inodes;
@@ -2055,10 +1610,13 @@ static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *s
info = SHMEM_I(inode);
inode->i_size = len-1;
- if (len <= SHMEM_SYMLINK_INLINE_LEN) {
- /* do it inline */
- memcpy(info->inline_symlink, symname, len);
- inode->i_op = &shmem_symlink_inline_operations;
+ if (len <= SHORT_SYMLINK_LEN) {
+ info->symlink = kmemdup(symname, len, GFP_KERNEL);
+ if (!info->symlink) {
+ iput(inode);
+ return -ENOMEM;
+ }
+ inode->i_op = &shmem_short_symlink_operations;
} else {
error = shmem_getpage(inode, 0, &page, SGP_WRITE, NULL);
if (error) {
@@ -2081,17 +1639,17 @@ static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *s
return 0;
}
-static void *shmem_follow_link_inline(struct dentry *dentry, struct nameidata *nd)
+static void *shmem_follow_short_symlink(struct dentry *dentry, struct nameidata *nd)
{
- nd_set_link(nd, SHMEM_I(dentry->d_inode)->inline_symlink);
+ nd_set_link(nd, SHMEM_I(dentry->d_inode)->symlink);
return NULL;
}
static void *shmem_follow_link(struct dentry *dentry, struct nameidata *nd)
{
struct page *page = NULL;
- int res = shmem_getpage(dentry->d_inode, 0, &page, SGP_READ, NULL);
- nd_set_link(nd, res ? ERR_PTR(res) : kmap(page));
+ int error = shmem_getpage(dentry->d_inode, 0, &page, SGP_READ, NULL);
+ nd_set_link(nd, error ? ERR_PTR(error) : kmap(page));
if (page)
unlock_page(page);
return page;
@@ -2202,7 +1760,6 @@ out:
return err;
}
-
static const struct xattr_handler *shmem_xattr_handlers[] = {
#ifdef CONFIG_TMPFS_POSIX_ACL
&generic_acl_access_handler,
@@ -2332,9 +1889,9 @@ static ssize_t shmem_listxattr(struct dentry *dentry, char *buffer, size_t size)
}
#endif /* CONFIG_TMPFS_XATTR */
-static const struct inode_operations shmem_symlink_inline_operations = {
+static const struct inode_operations shmem_short_symlink_operations = {
.readlink = generic_readlink,
- .follow_link = shmem_follow_link_inline,
+ .follow_link = shmem_follow_short_symlink,
#ifdef CONFIG_TMPFS_XATTR
.setxattr = shmem_setxattr,
.getxattr = shmem_getxattr,
@@ -2534,8 +2091,7 @@ static int shmem_remount_fs(struct super_block *sb, int *flags, char *data)
if (config.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;
+ * Those tests disallow limited->unlimited while any are in use;
* but we must separately disallow unlimited->limited, because
* in that case we have no record of how much is already in use.
*/
@@ -2627,7 +2183,7 @@ int shmem_fill_super(struct super_block *sb, void *data, int silent)
goto failed;
sbinfo->free_inodes = sbinfo->max_inodes;
- sb->s_maxbytes = SHMEM_MAX_BYTES;
+ sb->s_maxbytes = MAX_LFS_FILESIZE;
sb->s_blocksize = PAGE_CACHE_SIZE;
sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
sb->s_magic = TMPFS_MAGIC;
@@ -2662,14 +2218,14 @@ static struct kmem_cache *shmem_inode_cachep;
static struct inode *shmem_alloc_inode(struct super_block *sb)
{
- struct shmem_inode_info *p;
- p = (struct shmem_inode_info *)kmem_cache_alloc(shmem_inode_cachep, GFP_KERNEL);
- if (!p)
+ struct shmem_inode_info *info;
+ info = kmem_cache_alloc(shmem_inode_cachep, GFP_KERNEL);
+ if (!info)
return NULL;
- return &p->vfs_inode;
+ return &info->vfs_inode;
}
-static void shmem_i_callback(struct rcu_head *head)
+static void shmem_destroy_callback(struct rcu_head *head)
{
struct inode *inode = container_of(head, struct inode, i_rcu);
INIT_LIST_HEAD(&inode->i_dentry);
@@ -2678,29 +2234,26 @@ static void shmem_i_callback(struct rcu_head *head)
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 */
+ if ((inode->i_mode & S_IFMT) == S_IFREG)
mpol_free_shared_policy(&SHMEM_I(inode)->policy);
- }
- call_rcu(&inode->i_rcu, shmem_i_callback);
+ call_rcu(&inode->i_rcu, shmem_destroy_callback);
}
-static void init_once(void *foo)
+static void shmem_init_inode(void *foo)
{
- struct shmem_inode_info *p = (struct shmem_inode_info *) foo;
-
- inode_init_once(&p->vfs_inode);
+ struct shmem_inode_info *info = foo;
+ inode_init_once(&info->vfs_inode);
}
-static int init_inodecache(void)
+static int shmem_init_inodecache(void)
{
shmem_inode_cachep = kmem_cache_create("shmem_inode_cache",
sizeof(struct shmem_inode_info),
- 0, SLAB_PANIC, init_once);
+ 0, SLAB_PANIC, shmem_init_inode);
return 0;
}
-static void destroy_inodecache(void)
+static void shmem_destroy_inodecache(void)
{
kmem_cache_destroy(shmem_inode_cachep);
}
@@ -2797,21 +2350,20 @@ static const struct vm_operations_struct shmem_vm_ops = {
#endif
};
-
static struct dentry *shmem_mount(struct file_system_type *fs_type,
int flags, const char *dev_name, void *data)
{
return mount_nodev(fs_type, flags, data, shmem_fill_super);
}
-static struct file_system_type tmpfs_fs_type = {
+static struct file_system_type shmem_fs_type = {
.owner = THIS_MODULE,
.name = "tmpfs",
.mount = shmem_mount,
.kill_sb = kill_litter_super,
};
-int __init init_tmpfs(void)
+int __init shmem_init(void)
{
int error;
@@ -2819,18 +2371,18 @@ int __init init_tmpfs(void)
if (error)
goto out4;
- error = init_inodecache();
+ error = shmem_init_inodecache();
if (error)
goto out3;
- error = register_filesystem(&tmpfs_fs_type);
+ error = register_filesystem(&shmem_fs_type);
if (error) {
printk(KERN_ERR "Could not register tmpfs\n");
goto out2;
}
- shm_mnt = vfs_kern_mount(&tmpfs_fs_type, MS_NOUSER,
- tmpfs_fs_type.name, NULL);
+ shm_mnt = vfs_kern_mount(&shmem_fs_type, MS_NOUSER,
+ shmem_fs_type.name, NULL);
if (IS_ERR(shm_mnt)) {
error = PTR_ERR(shm_mnt);
printk(KERN_ERR "Could not kern_mount tmpfs\n");
@@ -2839,9 +2391,9 @@ int __init init_tmpfs(void)
return 0;
out1:
- unregister_filesystem(&tmpfs_fs_type);
+ unregister_filesystem(&shmem_fs_type);
out2:
- destroy_inodecache();
+ shmem_destroy_inodecache();
out3:
bdi_destroy(&shmem_backing_dev_info);
out4:
@@ -2849,45 +2401,6 @@ out4:
return error;
}
-#ifdef CONFIG_CGROUP_MEM_RES_CTLR
-/**
- * mem_cgroup_get_shmem_target - find a page or entry assigned to the shmem file
- * @inode: the inode to be searched
- * @pgoff: the offset to be searched
- * @pagep: the pointer for the found page to be stored
- * @ent: the pointer for the found swap entry to be stored
- *
- * If a page is found, refcount of it is incremented. Callers should handle
- * these refcount.
- */
-void mem_cgroup_get_shmem_target(struct inode *inode, pgoff_t pgoff,
- struct page **pagep, swp_entry_t *ent)
-{
- swp_entry_t entry = { .val = 0 }, *ptr;
- struct page *page = NULL;
- struct shmem_inode_info *info = SHMEM_I(inode);
-
- if ((pgoff << PAGE_CACHE_SHIFT) >= i_size_read(inode))
- goto out;
-
- spin_lock(&info->lock);
- ptr = shmem_swp_entry(info, pgoff, NULL);
-#ifdef CONFIG_SWAP
- if (ptr && ptr->val) {
- entry.val = ptr->val;
- page = find_get_page(&swapper_space, entry.val);
- } else
-#endif
- page = find_get_page(inode->i_mapping, pgoff);
- if (ptr)
- shmem_swp_unmap(ptr);
- spin_unlock(&info->lock);
-out:
- *pagep = page;
- *ent = entry;
-}
-#endif
-
#else /* !CONFIG_SHMEM */
/*
@@ -2901,23 +2414,23 @@ out:
#include <linux/ramfs.h>
-static struct file_system_type tmpfs_fs_type = {
+static struct file_system_type shmem_fs_type = {
.name = "tmpfs",
.mount = ramfs_mount,
.kill_sb = kill_litter_super,
};
-int __init init_tmpfs(void)
+int __init shmem_init(void)
{
- BUG_ON(register_filesystem(&tmpfs_fs_type) != 0);
+ BUG_ON(register_filesystem(&shmem_fs_type) != 0);
- shm_mnt = kern_mount(&tmpfs_fs_type);
+ shm_mnt = kern_mount(&shmem_fs_type);
BUG_ON(IS_ERR(shm_mnt));
return 0;
}
-int shmem_unuse(swp_entry_t entry, struct page *page)
+int shmem_unuse(swp_entry_t swap, struct page *page)
{
return 0;
}
@@ -2927,43 +2440,17 @@ int shmem_lock(struct file *file, int lock, struct user_struct *user)
return 0;
}
-void shmem_truncate_range(struct inode *inode, loff_t start, loff_t end)
+void shmem_truncate_range(struct inode *inode, loff_t lstart, loff_t lend)
{
- truncate_inode_pages_range(inode->i_mapping, start, end);
+ truncate_inode_pages_range(inode->i_mapping, lstart, lend);
}
EXPORT_SYMBOL_GPL(shmem_truncate_range);
-#ifdef CONFIG_CGROUP_MEM_RES_CTLR
-/**
- * mem_cgroup_get_shmem_target - find a page or entry assigned to the shmem file
- * @inode: the inode to be searched
- * @pgoff: the offset to be searched
- * @pagep: the pointer for the found page to be stored
- * @ent: the pointer for the found swap entry to be stored
- *
- * If a page is found, refcount of it is incremented. Callers should handle
- * these refcount.
- */
-void mem_cgroup_get_shmem_target(struct inode *inode, pgoff_t pgoff,
- struct page **pagep, swp_entry_t *ent)
-{
- struct page *page = NULL;
-
- if ((pgoff << PAGE_CACHE_SHIFT) >= i_size_read(inode))
- goto out;
- page = find_get_page(inode->i_mapping, pgoff);
-out:
- *pagep = page;
- *ent = (swp_entry_t){ .val = 0 };
-}
-#endif
-
#define shmem_vm_ops generic_file_vm_ops
#define shmem_file_operations ramfs_file_operations
#define shmem_get_inode(sb, dir, mode, dev, flags) ramfs_get_inode(sb, dir, mode, dev)
#define shmem_acct_size(flags, size) 0
#define shmem_unacct_size(flags, size) do {} while (0)
-#define SHMEM_MAX_BYTES MAX_LFS_FILESIZE
#endif /* CONFIG_SHMEM */
@@ -2987,7 +2474,7 @@ struct file *shmem_file_setup(const char *name, loff_t size, unsigned long flags
if (IS_ERR(shm_mnt))
return (void *)shm_mnt;
- if (size < 0 || size > SHMEM_MAX_BYTES)
+ if (size < 0 || size > MAX_LFS_FILESIZE)
return ERR_PTR(-EINVAL);
if (shmem_acct_size(flags, size))
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.