diff options
Diffstat (limited to 'mm/shmem.c')
| -rw-r--r-- | mm/shmem.c | 1996 |
1 files changed, 1164 insertions, 832 deletions
@@ -6,8 +6,7 @@ * 2000-2001 Christoph Rohland * 2000-2001 SAP AG * 2002 Red Hat Inc. - * Copyright (C) 2002-2011 Hugh Dickins. - * Copyright (C) 2011 Google Inc. + * Copyright (C) 2002-2005 Hugh Dickins. * Copyright (C) 2002-2005 VERITAS Software Corporation. * Copyright (C) 2004 Andi Kleen, SuSE Labs * @@ -28,7 +27,8 @@ #include <linux/pagemap.h> #include <linux/file.h> #include <linux/mm.h> -#include <linux/export.h> +#include <linux/module.h> +#include <linux/percpu_counter.h> #include <linux/swap.h> static struct vfsmount *shm_mnt; @@ -51,9 +51,6 @@ 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> #include <linux/mempolicy.h> @@ -65,27 +62,42 @@ 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) -/* Pretend that each entry is of this size in directory's i_size */ -#define BOGO_DIRENT_SIZE 20 +/* info->flags needs VM_flags to handle pagein/truncate races efficiently */ +#define SHMEM_PAGEIN VM_READ +#define SHMEM_TRUNCATE VM_WRITE -/* Symlink up to this size is kmalloc'ed instead of using a swappable page */ -#define SHORT_SYMLINK_LEN 128 +/* Definition to limit shmem_truncate's steps between cond_rescheds */ +#define LATENCY_LIMIT 64 -/* - * vmtruncate_range() communicates with shmem_fault via - * inode->i_private (with i_mutex making sure that it has only one user at - * a time): we would prefer not to enlarge the shmem inode just for that. - */ -struct shmem_falloc { - wait_queue_head_t *waitq; /* faults into hole wait for punch to end */ - pgoff_t start; /* start of range currently being fallocated */ - pgoff_t next; /* the next page offset to be fallocated */ -}; +/* Pretend that each entry is of this size in directory's i_size */ +#define BOGO_DIRENT_SIZE 20 struct shmem_xattr { struct list_head list; /* anchored by shmem_inode_info->xattr_list */ @@ -94,7 +106,7 @@ struct shmem_xattr { char value[0]; }; -/* Flag allocation requirements to shmem_getpage */ +/* Flag allocation requirements to shmem_getpage and shmem_swp_alloc */ enum sgp_type { SGP_READ, /* don't exceed i_size, don't allocate page */ SGP_CACHE, /* don't exceed i_size, may allocate page */ @@ -114,14 +126,57 @@ static unsigned long shmem_default_max_inodes(void) } #endif -static int shmem_getpage_gfp(struct inode *inode, pgoff_t index, - struct page **pagep, enum sgp_type sgp, gfp_t gfp, int *fault_type); +static int shmem_getpage(struct inode *inode, unsigned long idx, + struct page **pagep, enum sgp_type sgp, int *type); + +static inline struct page *shmem_dir_alloc(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 int shmem_getpage(struct inode *inode, pgoff_t index, - struct page **pagep, enum sgp_type sgp, int *fault_type) +static inline void shmem_dir_free(struct page *page) { - return shmem_getpage_gfp(inode, index, pagep, sgp, - mapping_gfp_mask(inode->i_mapping), fault_type); + __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) @@ -181,6 +236,17 @@ 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); + spin_lock(&inode->i_lock); + inode->i_blocks -= pages*BLOCKS_PER_PAGE; + spin_unlock(&inode->i_lock); + } +} + static int shmem_reserve_inode(struct super_block *sb) { struct shmem_sb_info *sbinfo = SHMEM_SB(sb); @@ -207,7 +273,7 @@ static void shmem_free_inode(struct super_block *sb) } /** - * shmem_recalc_inode - recalculate the block usage of an inode + * 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 @@ -225,335 +291,474 @@ 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); } } -/* - * Replace item expected in radix tree by a new item, while holding tree lock. - */ -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; -} - -/* - * Like add_to_page_cache_locked, but error if expected item has gone. +/** + * 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 int shmem_add_to_page_cache(struct page *page, - struct address_space *mapping, - pgoff_t index, gfp_t gfp, void *expected) +static swp_entry_t *shmem_swp_entry(struct shmem_inode_info *info, unsigned long index, struct page **page) { - int error = 0; - - VM_BUG_ON(!PageLocked(page)); - VM_BUG_ON(!PageSwapBacked(page)); + unsigned long offset; + struct page **dir; + struct page *subdir; - 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); + 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; } - if (!expected) - radix_tree_preload_end(); + return NULL; /* need another page */ } - if (error) - mem_cgroup_uncharge_cache_page(page); - return error; -} - -/* - * Like delete_from_page_cache, but substitutes swap for page. - */ -static void shmem_delete_from_page_cache(struct page *page, void *radswap) -{ - struct address_space *mapping = page->mapping; - int error; - 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); -} - -/* - * Like find_get_pages, but collecting swap entries as well as pages. - */ -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; + 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 */ } - if (!page_cache_get_speculative(page)) - goto repeat; + shmem_dir_unmap(dir); + dir = shmem_dir_map(subdir); + } - /* Has the page moved? */ - if (unlikely(page != *((void **)pages[i]))) { - page_cache_release(page); - goto repeat; + dir += index; + subdir = *dir; + if (!subdir) { + if (!page || !(subdir = *page)) { + shmem_dir_unmap(dir); + return NULL; /* need a page */ } -export: - indices[ret] = indices[i]; - pages[ret] = page; - ret++; - } - if (unlikely(!ret && nr_found)) - goto restart; - rcu_read_unlock(); - return ret; + *dir = subdir; + *page = NULL; + } + shmem_dir_unmap(dir); + return shmem_swp_map(subdir) + offset; } -/* - * Remove swap entry from radix tree, free the swap and its page cache. - */ -static int shmem_free_swap(struct address_space *mapping, - pgoff_t index, void *radswap) +static void shmem_swp_set(struct shmem_inode_info *info, swp_entry_t *entry, unsigned long value) { - 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; -} + long incdec = value? 1: -1; -/* - * Pagevec may contain swap entries, so shuffle up pages before releasing. - */ -static void shmem_deswap_pagevec(struct pagevec *pvec) -{ - 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; + 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); } - pvec->nr = j; } -/* - * SysV IPC SHM_UNLOCK restore Unevictable pages to their evictable lists. +/** + * 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? + * + * If the entry does not exist, allocate it. */ -void shmem_unlock_mapping(struct address_space *mapping) +static swp_entry_t *shmem_swp_alloc(struct shmem_inode_info *info, unsigned long index, enum sgp_type sgp) { - struct pagevec pvec; - pgoff_t indices[PAGEVEC_SIZE]; - pgoff_t index = 0; + struct inode *inode = &info->vfs_inode; + struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); + struct page *page = NULL; + swp_entry_t *entry; - pagevec_init(&pvec, 0); - /* - * Minor point, but we might as well stop if someone else SHM_LOCKs it. - */ - while (!mapping_unevictable(mapping)) { + 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)); /* - * Avoid pagevec_lookup(): find_get_pages() returns 0 as if it - * has finished, if it hits a row of PAGEVEC_SIZE swap entries. + * 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. */ - pvec.nr = shmem_find_get_pages_and_swap(mapping, index, - PAGEVEC_SIZE, pvec.pages, indices); - if (!pvec.nr) + 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); + spin_lock(&inode->i_lock); + inode->i_blocks += BLOCKS_PER_PAGE; + spin_unlock(&inode->i_lock); + } + + spin_unlock(&info->lock); + page = shmem_dir_alloc(mapping_gfp_mask(inode->i_mapping)); + 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; - index = indices[pvec.nr - 1] + 1; - shmem_deswap_pagevec(&pvec); - check_move_unevictable_pages(pvec.pages, pvec.nr); - pagevec_release(&pvec); - cond_resched(); + } + 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; } -/* - * Remove range of pages and swap entries from radix tree, and free them. +/** + * 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 */ -void shmem_truncate_range(struct inode *inode, loff_t lstart, loff_t lend) +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 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); +} + +void shmem_truncate_range(struct inode *inode, loff_t start, loff_t end) { - struct address_space *mapping = inode->i_mapping; struct shmem_inode_info *info = SHMEM_I(inode); - 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]; + 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; - pgoff_t index; - int i; - - BUG_ON((lend & (PAGE_CACHE_SIZE - 1)) != (PAGE_CACHE_SIZE - 1)); - - 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]; + int offset; + int freed; + int punch_hole; + spinlock_t *needs_lock; + spinlock_t *punch_lock; + unsigned long upper_limit; - index = indices[i]; - if (index > end) - break; + truncate_inode_pages_range(inode->i_mapping, start, end); - if (radix_tree_exceptional_entry(page)) { - nr_swaps_freed += !shmem_free_swap(mapping, - index, page); - continue; - } + inode->i_ctime = inode->i_mtime = CURRENT_TIME; + idx = (start + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; + if (idx >= info->next_index) + return; - if (!trylock_page(page)) - continue; - if (page->mapping == mapping) { - VM_BUG_ON(PageWriteback(page)); - truncate_inode_page(mapping, page); - } - unlock_page(page); + 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; } - shmem_deswap_pagevec(&pvec); - pagevec_release(&pvec); - mem_cgroup_uncharge_end(); - cond_resched(); - index++; + needs_lock = &info->lock; + punch_hole = 1; } - 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); - } + topdir = info->i_indirect; + if (topdir && idx <= SHMEM_NR_DIRECT && !punch_hole) { + info->i_indirect = NULL; + nr_pages_to_free++; + list_add(&topdir->lru, &pages_to_free); } + spin_unlock(&info->lock); - index = start; - while (index <= end) { - 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 all gone or hole-punch, we're done */ - if (index == start || end != -1) - break; - /* But if truncating, restart to make sure all gone */ - index = start; - continue; - } - mem_cgroup_uncharge_start(); - for (i = 0; i < pagevec_count(&pvec); i++) { - struct page *page = pvec.pages[i]; + 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); + } - index = indices[i]; - if (index > end) - break; + /* + * 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; - if (radix_tree_exceptional_entry(page)) { - if (shmem_free_swap(mapping, index, page)) { - /* Swap was replaced by page: retry */ - index--; - break; - } - nr_swaps_freed++; - continue; + /* + * The truncation case has already dropped info->lock, and we're safe + * because i_size and next_index have already been lowered, preventing + * access beyond. But in the punch_hole case, we still need to take + * the lock when updating the swap directory, because there might be + * racing accesses by shmem_getpage(SGP_CACHE), shmem_unuse_inode or + * shmem_writepage. However, whenever we find we can remove a whole + * directory page (not at the misaligned start or end of the range), + * we first NULLify its pointer in the level above, and then have no + * need to take the lock when updating its contents: needs_lock and + * punch_lock (either pointing to info->lock or NULL) manage this. + */ + + upper_limit -= SHMEM_NR_DIRECT; + limit -= SHMEM_NR_DIRECT; + idx = (idx > SHMEM_NR_DIRECT)? (idx - SHMEM_NR_DIRECT): 0; + offset = idx % ENTRIES_PER_PAGE; + idx -= offset; + + 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); } + shmem_dir_unmap(dir); + dir = shmem_dir_map(middir); + } else { + diroff = 0; + offset = 0; + idx = stage; + } + } - lock_page(page); - if (page->mapping == mapping) { - VM_BUG_ON(PageWriteback(page)); - truncate_inode_page(mapping, page); - } else { - /* Page was replaced by swap: retry */ - unlock_page(page); - index--; - break; + 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; } - unlock_page(page); + 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); + } + shmem_dir_unmap(dir); + cond_resched(); + dir = shmem_dir_map(middir); + diroff = 0; } - shmem_deswap_pagevec(&pvec); - pagevec_release(&pvec); - mem_cgroup_uncharge_end(); - index++; + 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); + } + 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); } 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); - inode->i_ctime = inode->i_mtime = CURRENT_TIME; + /* + * 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); + } } EXPORT_SYMBOL_GPL(shmem_truncate_range); @@ -569,7 +774,37 @@ 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; @@ -581,6 +816,8 @@ 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); @@ -605,39 +842,117 @@ 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); kfree(xattr); } - WARN_ON(inode->i_blocks); + BUG_ON(inode->i_blocks); shmem_free_inode(inode->i_sb); end_writeback(inode); } -/* - * 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) +static inline int shmem_find_swp(swp_entry_t entry, swp_entry_t *dir, swp_entry_t *edir) { - struct address_space *mapping = info->vfs_inode.i_mapping; - void *radswap; - pgoff_t index; + 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 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; int error; - radswap = swp_to_radix_entry(swap); - index = radix_tree_locate_item(&mapping->page_tree, radswap); - if (index == -1) - return 0; + 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; /* * 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. + * 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. */ if (shmem_swaplist.next != &info->swaplist) list_move_tail(&shmem_swaplist, &info->swaplist); @@ -647,34 +962,42 @@ static int shmem_unuse_inode(struct shmem_inode_info *info, * 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). */ - error = shmem_add_to_page_cache(page, mapping, index, - GFP_NOWAIT, radswap); + mapping = info->vfs_inode.i_mapping; + error = add_to_page_cache_locked(page, mapping, idx, GFP_NOWAIT); /* 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. - */ + if (error == -EEXIST) { + struct page *filepage = find_get_page(mapping, idx); + error = 1; + if (filepage) { + /* + * There might be a more uptodate page coming down + * from a stacked writepage: forget our swappage if so. + */ + if (PageUptodate(filepage)) + error = 0; + page_cache_release(filepage); + } + } + if (!error) { delete_from_swap_cache(page); set_page_dirty(page); - if (!error) { - spin_lock(&info->lock); - info->swapped--; - spin_unlock(&info->lock); - swap_free(swap); - } + info->flags |= SHMEM_PAGEIN; + shmem_swp_set(info, ptr, 0); + swap_free(entry); error = 1; /* not an error, but entry was found */ } + shmem_swp_unmap(ptr); + spin_unlock(&info->lock); return error; } /* - * Search through swapped inodes to find and replace swap by page. + * shmem_unuse() search for an eventually swapped out shmem page. */ -int shmem_unuse(swp_entry_t swap, struct page *page) +int shmem_unuse(swp_entry_t entry, struct page *page) { - struct list_head *this, *next; + struct list_head *p, *next; struct shmem_inode_info *info; int found = 0; int error; @@ -683,25 +1006,32 @@ int shmem_unuse(swp_entry_t swap, 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; - /* No radix_tree_preload: swap entry keeps a place for page in tree */ + /* + * 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(); mutex_lock(&shmem_swaplist_mutex); - 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); + list_for_each_safe(p, next, &shmem_swaplist) { + info = list_entry(p, struct shmem_inode_info, swaplist); + found = shmem_unuse_inode(info, entry, page); cond_resched(); if (found) break; } mutex_unlock(&shmem_swaplist_mutex); +uncharge: if (!found) mem_cgroup_uncharge_cache_page(page); if (found < 0) @@ -718,10 +1048,10 @@ 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; @@ -730,52 +1060,84 @@ static int shmem_writepage(struct page *page, struct writeback_control *wbc) info = SHMEM_I(inode); if (info->flags & VM_LOCKED) goto redirty; +#ifdef CONFIG_ZRAM_FOR_ANDROID + /* + * Modification for compcache + * shmem_writepage can be reason of kernel panic when using swap. + * This modification prevent using swap by shmem. + */ + goto redirty; +#else if (!total_swap_pages) goto redirty; +#endif /* * shmem_backing_dev_info's capabilities prevent regular writeback or * sync from ever calling shmem_writepage; but a stacking filesystem - * might use ->writepage of its underlying filesystem, in which case + * may use the ->writepage of its underlying filesystem, in which case * tmpfs should write out to swap only in response to memory pressure, - * and not for the writeback threads or sync. + * and not for the writeback threads or sync. However, in those cases, + * we do still want to check if there's a redundant swappage to be + * discarded. */ - if (!wbc->for_reclaim) { - WARN_ON_ONCE(1); /* Still happens? Tell us about it! */ - goto redirty; - } - swap = get_swap_page(); - if (!swap.val) - goto redirty; + if (wbc->for_reclaim) + swap = get_swap_page(); + else + swap.val = 0; /* * Add inode to shmem_unuse()'s list of swapped-out inodes, - * if it's not already there. Do it now before the page is - * moved to swap cache, when its pagelock no longer protects + * 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 * the inode from eviction. But don't unlock the mutex until - * we've incremented swapped, because shmem_unuse_inode() will - * prune a !swapped inode from the swaplist under this mutex. + * we've taken the spinlock, because shmem_unuse_inode() will + * prune a !swapped inode from the swaplist under both locks. */ - mutex_lock(&shmem_swaplist_mutex); - if (list_empty(&info->swaplist)) - list_add_tail(&info->swaplist, &shmem_swaplist); + if (swap.val) { + mutex_lock(&shmem_swaplist_mutex); + if (list_empty(&info->swaplist)) + list_add_tail(&info->swaplist, &shmem_swaplist); + } - if (add_to_swap_cache(page, swap, GFP_ATOMIC) == 0) { - swap_shmem_alloc(swap); - shmem_delete_from_page_cache(page, swp_to_radix_entry(swap)); + spin_lock(&info->lock); + if (swap.val) + mutex_unlock(&shmem_swaplist_mutex); - spin_lock(&info->lock); - info->swapped++; - shmem_recalc_inode(inode); - spin_unlock(&info->lock); + if (index >= info->next_index) { + BUG_ON(!(info->flags & SHMEM_TRUNCATE)); + goto unlock; + } + entry = shmem_swp_entry(info, index, NULL); + if (entry->val) { + /* + * The more uptodate page coming down from a stacked + * writepage should replace our old swappage. + */ + free_swap_and_cache(*entry); + shmem_swp_set(info, entry, 0); + } + shmem_recalc_inode(inode); - mutex_unlock(&shmem_swaplist_mutex); + if (swap.val && 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); + spin_unlock(&info->lock); BUG_ON(page_mapped(page)); swap_writepage(page, wbc); return 0; } - mutex_unlock(&shmem_swaplist_mutex); + 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. + */ swapcache_free(swap, NULL); redirty: set_page_dirty(page); @@ -812,19 +1174,19 @@ static struct mempolicy *shmem_get_sbmpol(struct shmem_sb_info *sbinfo) } #endif /* CONFIG_TMPFS */ -static struct page *shmem_swapin(swp_entry_t swap, gfp_t gfp, - struct shmem_inode_info *info, pgoff_t index) +static struct page *shmem_swapin(swp_entry_t entry, gfp_t gfp, + struct shmem_inode_info *info, unsigned long idx) { struct vm_area_struct pvma; struct page *page; /* Create a pseudo vma that just contains the policy */ pvma.vm_start = 0; - pvma.vm_pgoff = index; + pvma.vm_pgoff = idx; pvma.vm_ops = NULL; - pvma.vm_policy = mpol_shared_policy_lookup(&info->policy, index); + pvma.vm_policy = mpol_shared_policy_lookup(&info->policy, idx); - page = swapin_readahead(swap, gfp, &pvma, 0); + page = swapin_readahead(entry, gfp, &pvma, 0); /* Drop reference taken by mpol_shared_policy_lookup() */ mpol_cond_put(pvma.vm_policy); @@ -833,16 +1195,16 @@ static struct page *shmem_swapin(swp_entry_t swap, gfp_t gfp, } static struct page *shmem_alloc_page(gfp_t gfp, - struct shmem_inode_info *info, pgoff_t index) + struct shmem_inode_info *info, unsigned long idx) { struct vm_area_struct pvma; struct page *page; /* Create a pseudo vma that just contains the policy */ pvma.vm_start = 0; - pvma.vm_pgoff = index; + pvma.vm_pgoff = idx; pvma.vm_ops = NULL; - pvma.vm_policy = mpol_shared_policy_lookup(&info->policy, index); + pvma.vm_policy = mpol_shared_policy_lookup(&info->policy, idx); page = alloc_page_vma(gfp, &pvma, 0); @@ -853,19 +1215,19 @@ 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 *mpol) +static inline void shmem_show_mpol(struct seq_file *seq, struct mempolicy *p) { } #endif /* CONFIG_TMPFS */ -static inline struct page *shmem_swapin(swp_entry_t swap, gfp_t gfp, - struct shmem_inode_info *info, pgoff_t index) +static inline struct page *shmem_swapin(swp_entry_t entry, gfp_t gfp, + struct shmem_inode_info *info, unsigned long idx) { - return swapin_readahead(swap, gfp, NULL, 0); + return swapin_readahead(entry, gfp, NULL, 0); } static inline struct page *shmem_alloc_page(gfp_t gfp, - struct shmem_inode_info *info, pgoff_t index) + struct shmem_inode_info *info, unsigned long idx) { return alloc_page(gfp); } @@ -879,195 +1241,311 @@ static inline struct mempolicy *shmem_get_sbmpol(struct shmem_sb_info *sbinfo) #endif /* - * shmem_getpage_gfp - find page in cache, or get from swap, or allocate + * 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_gfp(struct inode *inode, pgoff_t index, - struct page **pagep, enum sgp_type sgp, gfp_t gfp, int *fault_type) +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; + struct shmem_inode_info *info = SHMEM_I(inode); struct shmem_sb_info *sbinfo; - struct page *page; + struct page *filepage = *pagep; + struct page *swappage; + struct page *prealloc_page = NULL; + swp_entry_t *entry; swp_entry_t swap; + gfp_t gfp; int error; - int once = 0; - if (index > (MAX_LFS_FILESIZE >> PAGE_CACHE_SHIFT)) + if (idx >= SHMEM_MAX_INDEX) return -EFBIG; -repeat: - 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 (type) + *type = 0; - if (page || (sgp == SGP_READ && !swap.val)) { + /* + * 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_readpage (required for splice) 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; + gfp = mapping_gfp_mask(mapping); + if (!filepage) { /* - * 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. + * Try to preload while we can wait, to not make a habit of + * draining atomic reserves; but don't latch on to this cpu. */ - BUG_ON(page && !PageUptodate(page)); - *pagep = page; - return 0; + error = radix_tree_preload(gfp & ~__GFP_HIGHMEM); + if (error) + goto failed; + radix_tree_preload_end(); + if (sgp != SGP_READ && !prealloc_page) { + /* We don't care if this fails */ + prealloc_page = shmem_alloc_page(gfp, info, idx); + if (prealloc_page) { + if (mem_cgroup_cache_charge(prealloc_page, + current->mm, GFP_KERNEL)) { + page_cache_release(prealloc_page); + prealloc_page = NULL; + } + } + } } + error = 0; - /* - * Fast cache lookup did not find it: - * bring it back from swap or allocate. - */ - info = SHMEM_I(inode); - sbinfo = SHMEM_SB(inode->i_sb); + 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.. */ - page = lookup_swap_cache(swap); - if (!page) { + swappage = lookup_swap_cache(swap); + if (!swappage) { + 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, index); - if (!page) { - error = -ENOMEM; - goto failed; + if (type) + *type |= VM_FAULT_MAJOR; + swappage = shmem_swapin(swap, gfp, info, 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 */ - lock_page(page); - if (!PageUptodate(page)) { - error = -EIO; - goto failed; + if (!trylock_page(swappage)) { + shmem_swp_unmap(entry); + spin_unlock(&info->lock); + wait_on_page_locked(swappage); + page_cache_release(swappage); + 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; + 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; } - - 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) + if (!PageUptodate(swappage)) { + shmem_swp_unmap(entry); + spin_unlock(&info->lock); + unlock_page(swappage); + page_cache_release(swappage); + error = -EIO; goto failed; + } - spin_lock(&info->lock); - info->swapped--; - shmem_recalc_inode(inode); + 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 = add_to_page_cache_locked(swappage, mapping, + idx, GFP_NOWAIT))) { + info->flags |= SHMEM_PAGEIN; + shmem_swp_set(info, entry, 0); + shmem_swp_unmap(entry); + delete_from_swap_cache(swappage); + spin_unlock(&info->lock); + filepage = swappage; + set_page_dirty(filepage); + swap_free(swap); + } else { + 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( + swappage, + current->mm, + gfp); + if (error) { + unlock_page(swappage); + page_cache_release(swappage); + goto failed; + } + } + unlock_page(swappage); + page_cache_release(swappage); + goto repeat; + } + } else if (sgp == SGP_READ && !filepage) { + shmem_swp_unmap(entry); + filepage = find_get_page(mapping, idx); + if (filepage && + (!PageUptodate(filepage) || !trylock_page(filepage))) { + spin_unlock(&info->lock); + wait_on_page_locked(filepage); + page_cache_release(filepage); + filepage = NULL; + goto repeat; + } spin_unlock(&info->lock); - - delete_from_swap_cache(page); - set_page_dirty(page); - swap_free(swap); - } else { - if (shmem_acct_block(info->flags)) { - error = -ENOSPC; - goto failed; - } + 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) { - error = -ENOSPC; - goto unacct; - } + sbinfo->max_blocks) >= 0 || + shmem_acct_block(info->flags)) + goto nospace; percpu_counter_inc(&sbinfo->used_blocks); - } + spin_lock(&inode->i_lock); + inode->i_blocks += BLOCKS_PER_PAGE; + spin_unlock(&inode->i_lock); + } else if (shmem_acct_block(info->flags)) + goto nospace; + + if (!filepage) { + int ret; + + if (!prealloc_page) { + spin_unlock(&info->lock); + filepage = shmem_alloc_page(gfp, info, idx); + if (!filepage) { + shmem_unacct_blocks(info->flags, 1); + shmem_free_blocks(inode, 1); + error = -ENOMEM; + goto failed; + } + SetPageSwapBacked(filepage); + + /* + * Precharge page while we can wait, compensate + * after + */ + error = mem_cgroup_cache_charge(filepage, + current->mm, GFP_KERNEL); + if (error) { + page_cache_release(filepage); + shmem_unacct_blocks(info->flags, 1); + shmem_free_blocks(inode, 1); + filepage = NULL; + goto failed; + } - page = shmem_alloc_page(gfp, info, index); - if (!page) { - error = -ENOMEM; - goto decused; - } + spin_lock(&info->lock); + } else { + filepage = prealloc_page; + prealloc_page = NULL; + SetPageSwapBacked(filepage); + } - 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); + entry = shmem_swp_alloc(info, idx, sgp); + 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(filepage); + else + ret = add_to_page_cache_lru(filepage, mapping, + idx, GFP_NOWAIT); + /* + * At add_to_page_cache_lru() failure, uncharge will + * be done automatically. + */ + if (ret) { + 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; + } - 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); + clear_highpage(filepage); + flush_dcache_page(filepage); + SetPageUptodate(filepage); if (sgp == SGP_DIRTY) - set_page_dirty(page); + set_page_dirty(filepage); } done: - /* 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; - } - *pagep = page; - return 0; + *pagep = filepage; + error = 0; + goto out; +nospace: /* - * Error recovery. + * 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. (When filepage has been passed in to shmem_getpage, it + * is already in page cache, which prevents this race from occurring.) */ -trunc: - ClearPageDirty(page); - delete_from_page_cache(page); - spin_lock(&info->lock); - info->alloced--; - inode->i_blocks -= BLOCKS_PER_PAGE; + if (!filepage) { + struct page *page = find_get_page(mapping, idx); + if (page) { + spin_unlock(&info->lock); + page_cache_release(page); + goto repeat; + } + } spin_unlock(&info->lock); -decused: - if (sbinfo->max_blocks) - percpu_counter_add(&sbinfo->used_blocks, -1); -unacct: - shmem_unacct_blocks(info->flags, 1); + error = -ENOSPC; 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 (*pagep != filepage) { + unlock_page(filepage); + page_cache_release(filepage); } - 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; +out: + if (prealloc_page) { + mem_cgroup_uncharge_cache_page(prealloc_page); + page_cache_release(prealloc_page); } - if (error == -EEXIST) - goto repeat; return error; } @@ -1075,132 +1553,36 @@ static int shmem_fault(struct vm_area_struct *vma, struct vm_fault *vmf) { struct inode *inode = vma->vm_file->f_path.dentry->d_inode; int error; - int ret = VM_FAULT_LOCKED; - - /* - * Trinity finds that probing a hole which tmpfs is punching can - * prevent the hole-punch from ever completing: which in turn - * locks writers out with its hold on i_mutex. So refrain from - * faulting pages into the hole while it's being punched. Although - * shmem_truncate_range() does remove the additions, it may be unable to - * keep up, as each new page needs its own unmap_mapping_range() call, - * and the i_mmap tree grows ever slower to scan if new vmas are added. - * - * It does not matter if we sometimes reach this check just before the - * hole-punch begins, so that one fault then races with the punch: - * we just need to make racing faults a rare case. - * - * The implementation below would be much simpler if we just used a - * standard mutex or completion: but we cannot take i_mutex in fault, - * and bloating every shmem inode for this unlikely case would be sad. - */ - if (unlikely(inode->i_private)) { - struct shmem_falloc *shmem_falloc; - - spin_lock(&inode->i_lock); - shmem_falloc = inode->i_private; - if (shmem_falloc && - vmf->pgoff >= shmem_falloc->start && - vmf->pgoff < shmem_falloc->next) { - wait_queue_head_t *shmem_falloc_waitq; - DEFINE_WAIT(shmem_fault_wait); - - ret = VM_FAULT_NOPAGE; - if ((vmf->flags & FAULT_FLAG_ALLOW_RETRY) && - !(vmf->flags & FAULT_FLAG_RETRY_NOWAIT)) { - /* It's polite to up mmap_sem if we can */ - up_read(&vma->vm_mm->mmap_sem); - ret = VM_FAULT_RETRY; - } - - shmem_falloc_waitq = shmem_falloc->waitq; - prepare_to_wait(shmem_falloc_waitq, &shmem_fault_wait, - TASK_UNINTERRUPTIBLE); - spin_unlock(&inode->i_lock); - schedule(); + int ret; - /* - * shmem_falloc_waitq points into the vmtruncate_range() - * stack of the hole-punching task: shmem_falloc_waitq - * is usually invalid by the time we reach here, but - * finish_wait() does not dereference it in that case; - * though i_lock needed lest racing with wake_up_all(). - */ - spin_lock(&inode->i_lock); - finish_wait(shmem_falloc_waitq, &shmem_fault_wait); - spin_unlock(&inode->i_lock); - return ret; - } - spin_unlock(&inode->i_lock); - } + 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); - if (ret & VM_FAULT_MAJOR) { count_vm_event(PGMAJFAULT); mem_cgroup_count_vm_event(vma->vm_mm, PGMAJFAULT); } - return ret; -} - -int vmtruncate_range(struct inode *inode, loff_t lstart, loff_t lend) -{ - /* - * If the underlying filesystem is not going to provide - * a way to truncate a range of blocks (punch a hole) - - * we should return failure right now. - * Only CONFIG_SHMEM shmem.c ever supported i_op->truncate_range(). - */ - if (inode->i_op->truncate_range != shmem_truncate_range) - return -ENOSYS; - - mutex_lock(&inode->i_mutex); - { - struct shmem_falloc shmem_falloc; - struct address_space *mapping = inode->i_mapping; - loff_t unmap_start = round_up(lstart, PAGE_SIZE); - loff_t unmap_end = round_down(1 + lend, PAGE_SIZE) - 1; - DECLARE_WAIT_QUEUE_HEAD_ONSTACK(shmem_falloc_waitq); - - shmem_falloc.waitq = &shmem_falloc_waitq; - shmem_falloc.start = unmap_start >> PAGE_SHIFT; - shmem_falloc.next = (unmap_end + 1) >> PAGE_SHIFT; - spin_lock(&inode->i_lock); - inode->i_private = &shmem_falloc; - spin_unlock(&inode->i_lock); - - if ((u64)unmap_end > (u64)unmap_start) - unmap_mapping_range(mapping, unmap_start, - 1 + unmap_end - unmap_start, 0); - shmem_truncate_range(inode, lstart, lend); - /* No need to unmap again: hole-punching leaves COWed pages */ - - spin_lock(&inode->i_lock); - inode->i_private = NULL; - wake_up_all(&shmem_falloc_waitq); - spin_unlock(&inode->i_lock); - } - mutex_unlock(&inode->i_mutex); - return 0; + return ret | VM_FAULT_LOCKED; } #ifdef CONFIG_NUMA -static int shmem_set_policy(struct vm_area_struct *vma, struct mempolicy *mpol) +static int shmem_set_policy(struct vm_area_struct *vma, struct mempolicy *new) { - struct inode *inode = vma->vm_file->f_path.dentry->d_inode; - return mpol_set_shared_policy(&SHMEM_I(inode)->policy, vma, mpol); + struct inode *i = vma->vm_file->f_path.dentry->d_inode; + return mpol_set_shared_policy(&SHMEM_I(i)->policy, vma, new); } static struct mempolicy *shmem_get_policy(struct vm_area_struct *vma, unsigned long addr) { - struct inode *inode = vma->vm_file->f_path.dentry->d_inode; - pgoff_t index; + struct inode *i = vma->vm_file->f_path.dentry->d_inode; + unsigned long idx; - index = ((addr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff; - return mpol_shared_policy_lookup(&SHMEM_I(inode)->policy, index); + idx = ((addr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff; + return mpol_shared_policy_lookup(&SHMEM_I(i)->policy, idx); } #endif @@ -1221,6 +1603,7 @@ int shmem_lock(struct file *file, int lock, struct user_struct *user) user_shm_unlock(inode->i_size, user); info->flags &= ~VM_LOCKED; mapping_clear_unevictable(file->f_mapping); + scan_mapping_unevictable_pages(file->f_mapping); } retval = 0; @@ -1297,7 +1680,20 @@ 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_short_symlink_operations; +static const struct inode_operations shmem_symlink_inline_operations; + +/* + * Normally tmpfs avoids the use of shmem_readpage and shmem_write_begin; + * but providing them allows a tmpfs file to be used for splice, sendfile, and + * below the loop driver, in the generic fashion that many filesystems support. + */ +static int shmem_readpage(struct file *file, struct page *page) +{ + struct inode *inode = page->mapping->host; + int error = shmem_getpage(inode, page->index, &page, SGP_CACHE, NULL); + unlock_page(page); + return error; +} static int shmem_write_begin(struct file *file, struct address_space *mapping, @@ -1306,6 +1702,7 @@ shmem_write_begin(struct file *file, struct address_space *mapping, { struct inode *inode = mapping->host; pgoff_t index = pos >> PAGE_CACHE_SHIFT; + *pagep = NULL; return shmem_getpage(inode, index, pagep, SGP_WRITE, NULL); } @@ -1330,8 +1727,7 @@ 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; - pgoff_t index; - unsigned long offset; + unsigned long index, offset; enum sgp_type sgp = SGP_READ; /* @@ -1347,8 +1743,7 @@ static void do_shmem_file_read(struct file *filp, loff_t *ppos, read_descriptor_ for (;;) { struct page *page = NULL; - pgoff_t end_index; - unsigned long nr, ret; + unsigned long end_index, nr, ret; loff_t i_size = i_size_read(inode); end_index = i_size >> PAGE_CACHE_SHIFT; @@ -1464,120 +1859,6 @@ static ssize_t shmem_file_aio_read(struct kiocb *iocb, return retval; } -static ssize_t shmem_file_splice_read(struct file *in, loff_t *ppos, - struct pipe_inode_info *pipe, size_t len, - unsigned int flags) -{ - struct address_space *mapping = in->f_mapping; - struct inode *inode = mapping->host; - unsigned int loff, nr_pages, req_pages; - struct page *pages[PIPE_DEF_BUFFERS]; - struct partial_page partial[PIPE_DEF_BUFFERS]; - struct page *page; - pgoff_t index, end_index; - loff_t isize, left; - int error, page_nr; - struct splice_pipe_desc spd = { - .pages = pages, - .partial = partial, - .nr_pages_max = PIPE_DEF_BUFFERS, - .flags = flags, - .ops = &page_cache_pipe_buf_ops, - .spd_release = spd_release_page, - }; - - isize = i_size_read(inode); - if (unlikely(*ppos >= isize)) - return 0; - - left = isize - *ppos; - if (unlikely(left < len)) - len = left; - - if (splice_grow_spd(pipe, &spd)) - return -ENOMEM; - - index = *ppos >> PAGE_CACHE_SHIFT; - loff = *ppos & ~PAGE_CACHE_MASK; - req_pages = (len + loff + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; - nr_pages = min(req_pages, pipe->buffers); - - spd.nr_pages = find_get_pages_contig(mapping, index, - nr_pages, spd.pages); - index += spd.nr_pages; - error = 0; - - while (spd.nr_pages < nr_pages) { - error = shmem_getpage(inode, index, &page, SGP_CACHE, NULL); - if (error) - break; - unlock_page(page); - spd.pages[spd.nr_pages++] = page; - index++; - } - - index = *ppos >> PAGE_CACHE_SHIFT; - nr_pages = spd.nr_pages; - spd.nr_pages = 0; - - for (page_nr = 0; page_nr < nr_pages; page_nr++) { - unsigned int this_len; - - if (!len) - break; - - this_len = min_t(unsigned long, len, PAGE_CACHE_SIZE - loff); - page = spd.pages[page_nr]; - - if (!PageUptodate(page) || page->mapping != mapping) { - error = shmem_getpage(inode, index, &page, - SGP_CACHE, NULL); - if (error) - break; - unlock_page(page); - page_cache_release(spd.pages[page_nr]); - spd.pages[page_nr] = page; - } - - isize = i_size_read(inode); - end_index = (isize - 1) >> PAGE_CACHE_SHIFT; - if (unlikely(!isize || index > end_index)) - break; - - if (end_index == index) { - unsigned int plen; - - plen = ((isize - 1) & ~PAGE_CACHE_MASK) + 1; - if (plen <= loff) - break; - - this_len = min(this_len, plen - loff); - len = this_len; - } - - spd.partial[page_nr].offset = loff; - spd.partial[page_nr].len = this_len; - len -= this_len; - loff = 0; - spd.nr_pages++; - index++; - } - - while (page_nr < nr_pages) - page_cache_release(spd.pages[page_nr++]); - - if (spd.nr_pages) - error = splice_to_pipe(pipe, &spd); - - splice_shrink_spd(&spd); - - if (error > 0) { - *ppos += error; - file_accessed(in); - } - return error; -} - static int shmem_statfs(struct dentry *dentry, struct kstatfs *buf) { struct shmem_sb_info *sbinfo = SHMEM_SB(dentry->d_sb); @@ -1587,9 +1868,8 @@ 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; @@ -1611,7 +1891,7 @@ shmem_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev) inode = shmem_get_inode(dir->i_sb, dir, mode, dev, VM_NORESERVE); if (inode) { error = security_inode_init_security(inode, dir, - &dentry->d_name, + &dentry->d_name, NULL, NULL, NULL); if (error) { if (error != -EOPNOTSUPP) { @@ -1719,10 +1999,8 @@ static int shmem_rename(struct inode *old_dir, struct dentry *old_dentry, struct if (new_dentry->d_inode) { (void) shmem_unlink(new_dir, new_dentry); - if (they_are_dirs) { - drop_nlink(new_dentry->d_inode); + if (they_are_dirs) drop_nlink(old_dir); - } } else if (they_are_dirs) { drop_nlink(old_dir); inc_nlink(new_dir); @@ -1741,7 +2019,7 @@ static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *s int error; int len; struct inode *inode; - struct page *page; + struct page *page = NULL; char *kaddr; struct shmem_inode_info *info; @@ -1753,7 +2031,7 @@ static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *s if (!inode) return -ENOSPC; - error = security_inode_init_security(inode, dir, &dentry->d_name, + error = security_inode_init_security(inode, dir, &dentry->d_name, NULL, NULL, NULL); if (error) { if (error != -EOPNOTSUPP) { @@ -1765,13 +2043,10 @@ static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *s info = SHMEM_I(inode); inode->i_size = len-1; - 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; + if (len <= SHMEM_SYMLINK_INLINE_LEN) { + /* do it inline */ + memcpy(info->inline_symlink, symname, len); + inode->i_op = &shmem_symlink_inline_operations; } else { error = shmem_getpage(inode, 0, &page, SGP_WRITE, NULL); if (error) { @@ -1794,17 +2069,17 @@ static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *s return 0; } -static void *shmem_follow_short_symlink(struct dentry *dentry, struct nameidata *nd) +static void *shmem_follow_link_inline(struct dentry *dentry, struct nameidata *nd) { - nd_set_link(nd, SHMEM_I(dentry->d_inode)->symlink); + nd_set_link(nd, SHMEM_I(dentry->d_inode)->inline_symlink); return NULL; } static void *shmem_follow_link(struct dentry *dentry, struct nameidata *nd) { struct page *page = NULL; - int error = shmem_getpage(dentry->d_inode, 0, &page, SGP_READ, NULL); - nd_set_link(nd, error ? ERR_PTR(error) : kmap(page)); + int res = shmem_getpage(dentry->d_inode, 0, &page, SGP_READ, NULL); + nd_set_link(nd, res ? ERR_PTR(res) : kmap(page)); if (page) unlock_page(page); return page; @@ -1915,6 +2190,7 @@ out: return err; } + static const struct xattr_handler *shmem_xattr_handlers[] = { #ifdef CONFIG_TMPFS_POSIX_ACL &generic_acl_access_handler, @@ -2044,9 +2320,9 @@ static ssize_t shmem_listxattr(struct dentry *dentry, char *buffer, size_t size) } #endif /* CONFIG_TMPFS_XATTR */ -static const struct inode_operations shmem_short_symlink_operations = { +static const struct inode_operations shmem_symlink_inline_operations = { .readlink = generic_readlink, - .follow_link = shmem_follow_short_symlink, + .follow_link = shmem_follow_link_inline, #ifdef CONFIG_TMPFS_XATTR .setxattr = shmem_setxattr, .getxattr = shmem_getxattr, @@ -2249,7 +2525,8 @@ static int shmem_remount_fs(struct super_block *sb, int *flags, char *data) if (config.max_inodes < inodes) goto out; /* - * Those tests disallow limited->unlimited while any are in use; + * 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. */ @@ -2346,7 +2623,7 @@ int shmem_fill_super(struct super_block *sb, void *data, int silent) goto failed; sbinfo->free_inodes = sbinfo->max_inodes; - sb->s_maxbytes = MAX_LFS_FILESIZE; + sb->s_maxbytes = SHMEM_MAX_BYTES; sb->s_blocksize = PAGE_CACHE_SIZE; sb->s_blocksize_bits = PAGE_CACHE_SHIFT; sb->s_magic = TMPFS_MAGIC; @@ -2381,14 +2658,14 @@ static struct kmem_cache *shmem_inode_cachep; static struct inode *shmem_alloc_inode(struct super_block *sb) { - struct shmem_inode_info *info; - info = kmem_cache_alloc(shmem_inode_cachep, GFP_KERNEL); - if (!info) + struct shmem_inode_info *p; + p = (struct shmem_inode_info *)kmem_cache_alloc(shmem_inode_cachep, GFP_KERNEL); + if (!p) return NULL; - return &info->vfs_inode; + return &p->vfs_inode; } -static void shmem_destroy_callback(struct rcu_head *head) +static void shmem_i_callback(struct rcu_head *head) { struct inode *inode = container_of(head, struct inode, i_rcu); INIT_LIST_HEAD(&inode->i_dentry); @@ -2397,26 +2674,29 @@ static void shmem_destroy_callback(struct rcu_head *head) static void shmem_destroy_inode(struct inode *inode) { - if ((inode->i_mode & S_IFMT) == S_IFREG) + 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); - call_rcu(&inode->i_rcu, shmem_destroy_callback); + } + call_rcu(&inode->i_rcu, shmem_i_callback); } -static void shmem_init_inode(void *foo) +static void init_once(void *foo) { - struct shmem_inode_info *info = foo; - inode_init_once(&info->vfs_inode); + struct shmem_inode_info *p = (struct shmem_inode_info *) foo; + + inode_init_once(&p->vfs_inode); } -static int shmem_init_inodecache(void) +static int init_inodecache(void) { shmem_inode_cachep = kmem_cache_create("shmem_inode_cache", sizeof(struct shmem_inode_info), - 0, SLAB_PANIC, shmem_init_inode); + 0, SLAB_PANIC, init_once); return 0; } -static void shmem_destroy_inodecache(void) +static void destroy_inodecache(void) { kmem_cache_destroy(shmem_inode_cachep); } @@ -2425,6 +2705,7 @@ static const struct address_space_operations shmem_aops = { .writepage = shmem_writepage, .set_page_dirty = __set_page_dirty_no_writeback, #ifdef CONFIG_TMPFS + .readpage = shmem_readpage, .write_begin = shmem_write_begin, .write_end = shmem_write_end, #endif @@ -2441,7 +2722,7 @@ static const struct file_operations shmem_file_operations = { .aio_read = shmem_file_aio_read, .aio_write = generic_file_aio_write, .fsync = noop_fsync, - .splice_read = shmem_file_splice_read, + .splice_read = generic_file_splice_read, .splice_write = generic_file_splice_write, #endif }; @@ -2455,6 +2736,10 @@ static const struct inode_operations shmem_inode_operations = { .listxattr = shmem_listxattr, .removexattr = shmem_removexattr, #endif +#ifdef CONFIG_TMPFS_POSIX_ACL + .check_acl = generic_check_acl, +#endif + }; static const struct inode_operations shmem_dir_inode_operations = { @@ -2477,6 +2762,7 @@ static const struct inode_operations shmem_dir_inode_operations = { #endif #ifdef CONFIG_TMPFS_POSIX_ACL .setattr = shmem_setattr, + .check_acl = generic_check_acl, #endif }; @@ -2489,6 +2775,7 @@ static const struct inode_operations shmem_special_inode_operations = { #endif #ifdef CONFIG_TMPFS_POSIX_ACL .setattr = shmem_setattr, + .check_acl = generic_check_acl, #endif }; @@ -2513,20 +2800,21 @@ 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 shmem_fs_type = { +static struct file_system_type tmpfs_fs_type = { .owner = THIS_MODULE, .name = "tmpfs", .mount = shmem_mount, .kill_sb = kill_litter_super, }; -int __init shmem_init(void) +int __init init_tmpfs(void) { int error; @@ -2534,18 +2822,18 @@ int __init shmem_init(void) if (error) goto out4; - error = shmem_init_inodecache(); + error = init_inodecache(); if (error) goto out3; - error = register_filesystem(&shmem_fs_type); + error = register_filesystem(&tmpfs_fs_type); if (error) { printk(KERN_ERR "Could not register tmpfs\n"); goto out2; } - shm_mnt = vfs_kern_mount(&shmem_fs_type, MS_NOUSER, - shmem_fs_type.name, NULL); + shm_mnt = vfs_kern_mount(&tmpfs_fs_type, MS_NOUSER, + tmpfs_fs_type.name, NULL); if (IS_ERR(shm_mnt)) { error = PTR_ERR(shm_mnt); printk(KERN_ERR "Could not kern_mount tmpfs\n"); @@ -2554,9 +2842,9 @@ int __init shmem_init(void) return 0; out1: - unregister_filesystem(&shmem_fs_type); + unregister_filesystem(&tmpfs_fs_type); out2: - shmem_destroy_inodecache(); + destroy_inodecache(); out3: bdi_destroy(&shmem_backing_dev_info); out4: @@ -2564,6 +2852,45 @@ 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 */ /* @@ -2577,23 +2904,23 @@ out4: #include <linux/ramfs.h> -static struct file_system_type shmem_fs_type = { +static struct file_system_type tmpfs_fs_type = { .name = "tmpfs", .mount = ramfs_mount, .kill_sb = kill_litter_super, }; -int __init shmem_init(void) +int __init init_tmpfs(void) { - BUG_ON(register_filesystem(&shmem_fs_type) != 0); + BUG_ON(register_filesystem(&tmpfs_fs_type) != 0); - shm_mnt = kern_mount(&shmem_fs_type); + shm_mnt = kern_mount(&tmpfs_fs_type); BUG_ON(IS_ERR(shm_mnt)); return 0; } -int shmem_unuse(swp_entry_t swap, struct page *page) +int shmem_unuse(swp_entry_t entry, struct page *page) { return 0; } @@ -2603,27 +2930,43 @@ int shmem_lock(struct file *file, int lock, struct user_struct *user) return 0; } -void shmem_unlock_mapping(struct address_space *mapping) -{ -} - -void shmem_truncate_range(struct inode *inode, loff_t lstart, loff_t lend) +void shmem_truncate_range(struct inode *inode, loff_t start, loff_t end) { - truncate_inode_pages_range(inode->i_mapping, lstart, lend); + truncate_inode_pages_range(inode->i_mapping, start, end); } EXPORT_SYMBOL_GPL(shmem_truncate_range); -int vmtruncate_range(struct inode *inode, loff_t lstart, loff_t lend) +#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) { - /* Only CONFIG_SHMEM shmem.c ever supported i_op->truncate_range(). */ - return -ENOSYS; + 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 */ @@ -2647,7 +2990,7 @@ 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 > MAX_LFS_FILESIZE) + if (size < 0 || size > SHMEM_MAX_BYTES) return ERR_PTR(-EINVAL); if (shmem_acct_size(flags, size)) @@ -2670,7 +3013,7 @@ struct file *shmem_file_setup(const char *name, loff_t size, unsigned long flags d_instantiate(path.dentry, inode); inode->i_size = size; - clear_nlink(inode); /* It is unlinked */ + inode->i_nlink = 0; /* It is unlinked */ #ifndef CONFIG_MMU error = ramfs_nommu_expand_for_mapping(inode, size); if (error) @@ -2693,6 +3036,15 @@ put_memory: } EXPORT_SYMBOL_GPL(shmem_file_setup); +void shmem_set_file(struct vm_area_struct *vma, struct file *file) +{ + if (vma->vm_file) + fput(vma->vm_file); + vma->vm_file = file; + vma->vm_ops = &shmem_vm_ops; + vma->vm_flags |= VM_CAN_NONLINEAR; +} + /** * shmem_zero_setup - setup a shared anonymous mapping * @vma: the vma to be mmapped is prepared by do_mmap_pgoff @@ -2706,11 +3058,7 @@ int shmem_zero_setup(struct vm_area_struct *vma) 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; - vma->vm_flags |= VM_CAN_NONLINEAR; + shmem_set_file(vma, file); return 0; } @@ -2726,29 +3074,13 @@ int shmem_zero_setup(struct vm_area_struct *vma) * suit tmpfs, since it may have pages in swapcache, and needs to find those * for itself; although drivers/gpu/drm i915 and ttm rely upon this support. * - * i915_gem_object_get_pages_gtt() mixes __GFP_NORETRY | __GFP_NOWARN in - * with the mapping_gfp_mask(), to avoid OOMing the machine unnecessarily. + * Provide a stub for those callers to start using now, then later + * flesh it out to call shmem_getpage() with additional gfp mask, when + * shmem_file_splice_read() is added and shmem_readpage() is removed. */ struct page *shmem_read_mapping_page_gfp(struct address_space *mapping, pgoff_t index, gfp_t gfp) { -#ifdef CONFIG_SHMEM - struct inode *inode = mapping->host; - struct page *page; - int error; - - BUG_ON(mapping->a_ops != &shmem_aops); - error = shmem_getpage_gfp(inode, index, &page, SGP_CACHE, gfp, NULL); - if (error) - page = ERR_PTR(error); - else - unlock_page(page); - return page; -#else - /* - * The tiny !SHMEM case uses ramfs without swap - */ return read_cache_page_gfp(mapping, index, gfp); -#endif } EXPORT_SYMBOL_GPL(shmem_read_mapping_page_gfp); |