mirror of https://github.com/Qortal/Brooklyn
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
870 lines
26 KiB
870 lines
26 KiB
// SPDX-License-Identifier: GPL-2.0-only |
|
/* |
|
* mm/truncate.c - code for taking down pages from address_spaces |
|
* |
|
* Copyright (C) 2002, Linus Torvalds |
|
* |
|
* 10Sep2002 Andrew Morton |
|
* Initial version. |
|
*/ |
|
|
|
#include <linux/kernel.h> |
|
#include <linux/backing-dev.h> |
|
#include <linux/dax.h> |
|
#include <linux/gfp.h> |
|
#include <linux/mm.h> |
|
#include <linux/swap.h> |
|
#include <linux/export.h> |
|
#include <linux/pagemap.h> |
|
#include <linux/highmem.h> |
|
#include <linux/pagevec.h> |
|
#include <linux/task_io_accounting_ops.h> |
|
#include <linux/buffer_head.h> /* grr. try_to_release_page, |
|
do_invalidatepage */ |
|
#include <linux/shmem_fs.h> |
|
#include <linux/cleancache.h> |
|
#include <linux/rmap.h> |
|
#include "internal.h" |
|
|
|
/* |
|
* Regular page slots are stabilized by the page lock even without the tree |
|
* itself locked. These unlocked entries need verification under the tree |
|
* lock. |
|
*/ |
|
static inline void __clear_shadow_entry(struct address_space *mapping, |
|
pgoff_t index, void *entry) |
|
{ |
|
XA_STATE(xas, &mapping->i_pages, index); |
|
|
|
xas_set_update(&xas, workingset_update_node); |
|
if (xas_load(&xas) != entry) |
|
return; |
|
xas_store(&xas, NULL); |
|
mapping->nrexceptional--; |
|
} |
|
|
|
static void clear_shadow_entry(struct address_space *mapping, pgoff_t index, |
|
void *entry) |
|
{ |
|
xa_lock_irq(&mapping->i_pages); |
|
__clear_shadow_entry(mapping, index, entry); |
|
xa_unlock_irq(&mapping->i_pages); |
|
} |
|
|
|
/* |
|
* Unconditionally remove exceptional entries. Usually called from truncate |
|
* path. Note that the pagevec may be altered by this function by removing |
|
* exceptional entries similar to what pagevec_remove_exceptionals does. |
|
*/ |
|
static void truncate_exceptional_pvec_entries(struct address_space *mapping, |
|
struct pagevec *pvec, pgoff_t *indices) |
|
{ |
|
int i, j; |
|
bool dax; |
|
|
|
/* Handled by shmem itself */ |
|
if (shmem_mapping(mapping)) |
|
return; |
|
|
|
for (j = 0; j < pagevec_count(pvec); j++) |
|
if (xa_is_value(pvec->pages[j])) |
|
break; |
|
|
|
if (j == pagevec_count(pvec)) |
|
return; |
|
|
|
dax = dax_mapping(mapping); |
|
if (!dax) |
|
xa_lock_irq(&mapping->i_pages); |
|
|
|
for (i = j; i < pagevec_count(pvec); i++) { |
|
struct page *page = pvec->pages[i]; |
|
pgoff_t index = indices[i]; |
|
|
|
if (!xa_is_value(page)) { |
|
pvec->pages[j++] = page; |
|
continue; |
|
} |
|
|
|
if (unlikely(dax)) { |
|
dax_delete_mapping_entry(mapping, index); |
|
continue; |
|
} |
|
|
|
__clear_shadow_entry(mapping, index, page); |
|
} |
|
|
|
if (!dax) |
|
xa_unlock_irq(&mapping->i_pages); |
|
pvec->nr = j; |
|
} |
|
|
|
/* |
|
* Invalidate exceptional entry if easily possible. This handles exceptional |
|
* entries for invalidate_inode_pages(). |
|
*/ |
|
static int invalidate_exceptional_entry(struct address_space *mapping, |
|
pgoff_t index, void *entry) |
|
{ |
|
/* Handled by shmem itself, or for DAX we do nothing. */ |
|
if (shmem_mapping(mapping) || dax_mapping(mapping)) |
|
return 1; |
|
clear_shadow_entry(mapping, index, entry); |
|
return 1; |
|
} |
|
|
|
/* |
|
* Invalidate exceptional entry if clean. This handles exceptional entries for |
|
* invalidate_inode_pages2() so for DAX it evicts only clean entries. |
|
*/ |
|
static int invalidate_exceptional_entry2(struct address_space *mapping, |
|
pgoff_t index, void *entry) |
|
{ |
|
/* Handled by shmem itself */ |
|
if (shmem_mapping(mapping)) |
|
return 1; |
|
if (dax_mapping(mapping)) |
|
return dax_invalidate_mapping_entry_sync(mapping, index); |
|
clear_shadow_entry(mapping, index, entry); |
|
return 1; |
|
} |
|
|
|
/** |
|
* do_invalidatepage - invalidate part or all of a page |
|
* @page: the page which is affected |
|
* @offset: start of the range to invalidate |
|
* @length: length of the range to invalidate |
|
* |
|
* do_invalidatepage() is called when all or part of the page has become |
|
* invalidated by a truncate operation. |
|
* |
|
* do_invalidatepage() does not have to release all buffers, but it must |
|
* ensure that no dirty buffer is left outside @offset and that no I/O |
|
* is underway against any of the blocks which are outside the truncation |
|
* point. Because the caller is about to free (and possibly reuse) those |
|
* blocks on-disk. |
|
*/ |
|
void do_invalidatepage(struct page *page, unsigned int offset, |
|
unsigned int length) |
|
{ |
|
void (*invalidatepage)(struct page *, unsigned int, unsigned int); |
|
|
|
invalidatepage = page->mapping->a_ops->invalidatepage; |
|
#ifdef CONFIG_BLOCK |
|
if (!invalidatepage) |
|
invalidatepage = block_invalidatepage; |
|
#endif |
|
if (invalidatepage) |
|
(*invalidatepage)(page, offset, length); |
|
} |
|
|
|
/* |
|
* If truncate cannot remove the fs-private metadata from the page, the page |
|
* becomes orphaned. It will be left on the LRU and may even be mapped into |
|
* user pagetables if we're racing with filemap_fault(). |
|
* |
|
* We need to bail out if page->mapping is no longer equal to the original |
|
* mapping. This happens a) when the VM reclaimed the page while we waited on |
|
* its lock, b) when a concurrent invalidate_mapping_pages got there first and |
|
* c) when tmpfs swizzles a page between a tmpfs inode and swapper_space. |
|
*/ |
|
static void |
|
truncate_cleanup_page(struct address_space *mapping, struct page *page) |
|
{ |
|
if (page_mapped(page)) { |
|
unsigned int nr = thp_nr_pages(page); |
|
unmap_mapping_pages(mapping, page->index, nr, false); |
|
} |
|
|
|
if (page_has_private(page)) |
|
do_invalidatepage(page, 0, thp_size(page)); |
|
|
|
/* |
|
* Some filesystems seem to re-dirty the page even after |
|
* the VM has canceled the dirty bit (eg ext3 journaling). |
|
* Hence dirty accounting check is placed after invalidation. |
|
*/ |
|
cancel_dirty_page(page); |
|
ClearPageMappedToDisk(page); |
|
} |
|
|
|
/* |
|
* This is for invalidate_mapping_pages(). That function can be called at |
|
* any time, and is not supposed to throw away dirty pages. But pages can |
|
* be marked dirty at any time too, so use remove_mapping which safely |
|
* discards clean, unused pages. |
|
* |
|
* Returns non-zero if the page was successfully invalidated. |
|
*/ |
|
static int |
|
invalidate_complete_page(struct address_space *mapping, struct page *page) |
|
{ |
|
int ret; |
|
|
|
if (page->mapping != mapping) |
|
return 0; |
|
|
|
if (page_has_private(page) && !try_to_release_page(page, 0)) |
|
return 0; |
|
|
|
ret = remove_mapping(mapping, page); |
|
|
|
return ret; |
|
} |
|
|
|
int truncate_inode_page(struct address_space *mapping, struct page *page) |
|
{ |
|
VM_BUG_ON_PAGE(PageTail(page), page); |
|
|
|
if (page->mapping != mapping) |
|
return -EIO; |
|
|
|
truncate_cleanup_page(mapping, page); |
|
delete_from_page_cache(page); |
|
return 0; |
|
} |
|
|
|
/* |
|
* Used to get rid of pages on hardware memory corruption. |
|
*/ |
|
int generic_error_remove_page(struct address_space *mapping, struct page *page) |
|
{ |
|
if (!mapping) |
|
return -EINVAL; |
|
/* |
|
* Only punch for normal data pages for now. |
|
* Handling other types like directories would need more auditing. |
|
*/ |
|
if (!S_ISREG(mapping->host->i_mode)) |
|
return -EIO; |
|
return truncate_inode_page(mapping, page); |
|
} |
|
EXPORT_SYMBOL(generic_error_remove_page); |
|
|
|
/* |
|
* Safely invalidate one page from its pagecache mapping. |
|
* It only drops clean, unused pages. The page must be locked. |
|
* |
|
* Returns 1 if the page is successfully invalidated, otherwise 0. |
|
*/ |
|
int invalidate_inode_page(struct page *page) |
|
{ |
|
struct address_space *mapping = page_mapping(page); |
|
if (!mapping) |
|
return 0; |
|
if (PageDirty(page) || PageWriteback(page)) |
|
return 0; |
|
if (page_mapped(page)) |
|
return 0; |
|
return invalidate_complete_page(mapping, page); |
|
} |
|
|
|
/** |
|
* truncate_inode_pages_range - truncate range of pages specified by start & end byte offsets |
|
* @mapping: mapping to truncate |
|
* @lstart: offset from which to truncate |
|
* @lend: offset to which to truncate (inclusive) |
|
* |
|
* Truncate the page cache, removing the pages that are between |
|
* specified offsets (and zeroing out partial pages |
|
* if lstart or lend + 1 is not page aligned). |
|
* |
|
* Truncate takes two passes - the first pass is nonblocking. It will not |
|
* block on page locks and it will not block on writeback. The second pass |
|
* will wait. This is to prevent as much IO as possible in the affected region. |
|
* The first pass will remove most pages, so the search cost of the second pass |
|
* is low. |
|
* |
|
* We pass down the cache-hot hint to the page freeing code. Even if the |
|
* mapping is large, it is probably the case that the final pages are the most |
|
* recently touched, and freeing happens in ascending file offset order. |
|
* |
|
* Note that since ->invalidatepage() accepts range to invalidate |
|
* truncate_inode_pages_range is able to handle cases where lend + 1 is not |
|
* page aligned properly. |
|
*/ |
|
void truncate_inode_pages_range(struct address_space *mapping, |
|
loff_t lstart, loff_t lend) |
|
{ |
|
pgoff_t start; /* inclusive */ |
|
pgoff_t end; /* exclusive */ |
|
unsigned int partial_start; /* inclusive */ |
|
unsigned int partial_end; /* exclusive */ |
|
struct pagevec pvec; |
|
pgoff_t indices[PAGEVEC_SIZE]; |
|
pgoff_t index; |
|
int i; |
|
|
|
if (mapping->nrpages == 0 && mapping->nrexceptional == 0) |
|
goto out; |
|
|
|
/* Offsets within partial pages */ |
|
partial_start = lstart & (PAGE_SIZE - 1); |
|
partial_end = (lend + 1) & (PAGE_SIZE - 1); |
|
|
|
/* |
|
* 'start' and 'end' always covers the range of pages to be fully |
|
* truncated. Partial pages are covered with 'partial_start' at the |
|
* start of the range and 'partial_end' at the end of the range. |
|
* Note that 'end' is exclusive while 'lend' is inclusive. |
|
*/ |
|
start = (lstart + PAGE_SIZE - 1) >> PAGE_SHIFT; |
|
if (lend == -1) |
|
/* |
|
* lend == -1 indicates end-of-file so we have to set 'end' |
|
* to the highest possible pgoff_t and since the type is |
|
* unsigned we're using -1. |
|
*/ |
|
end = -1; |
|
else |
|
end = (lend + 1) >> PAGE_SHIFT; |
|
|
|
pagevec_init(&pvec); |
|
index = start; |
|
while (index < end && find_lock_entries(mapping, index, end - 1, |
|
&pvec, indices)) { |
|
index = indices[pagevec_count(&pvec) - 1] + 1; |
|
truncate_exceptional_pvec_entries(mapping, &pvec, indices); |
|
for (i = 0; i < pagevec_count(&pvec); i++) |
|
truncate_cleanup_page(mapping, pvec.pages[i]); |
|
delete_from_page_cache_batch(mapping, &pvec); |
|
for (i = 0; i < pagevec_count(&pvec); i++) |
|
unlock_page(pvec.pages[i]); |
|
pagevec_release(&pvec); |
|
cond_resched(); |
|
} |
|
|
|
if (partial_start) { |
|
struct page *page = find_lock_page(mapping, start - 1); |
|
if (page) { |
|
unsigned int top = PAGE_SIZE; |
|
if (start > end) { |
|
/* Truncation within a single page */ |
|
top = partial_end; |
|
partial_end = 0; |
|
} |
|
wait_on_page_writeback(page); |
|
zero_user_segment(page, partial_start, top); |
|
cleancache_invalidate_page(mapping, page); |
|
if (page_has_private(page)) |
|
do_invalidatepage(page, partial_start, |
|
top - partial_start); |
|
unlock_page(page); |
|
put_page(page); |
|
} |
|
} |
|
if (partial_end) { |
|
struct page *page = find_lock_page(mapping, end); |
|
if (page) { |
|
wait_on_page_writeback(page); |
|
zero_user_segment(page, 0, partial_end); |
|
cleancache_invalidate_page(mapping, page); |
|
if (page_has_private(page)) |
|
do_invalidatepage(page, 0, |
|
partial_end); |
|
unlock_page(page); |
|
put_page(page); |
|
} |
|
} |
|
/* |
|
* If the truncation happened within a single page no pages |
|
* will be released, just zeroed, so we can bail out now. |
|
*/ |
|
if (start >= end) |
|
goto out; |
|
|
|
index = start; |
|
for ( ; ; ) { |
|
cond_resched(); |
|
if (!find_get_entries(mapping, index, end - 1, &pvec, |
|
indices)) { |
|
/* If all gone from start onwards, we're done */ |
|
if (index == start) |
|
break; |
|
/* Otherwise restart to make sure all gone */ |
|
index = start; |
|
continue; |
|
} |
|
|
|
for (i = 0; i < pagevec_count(&pvec); i++) { |
|
struct page *page = pvec.pages[i]; |
|
|
|
/* We rely upon deletion not changing page->index */ |
|
index = indices[i]; |
|
|
|
if (xa_is_value(page)) |
|
continue; |
|
|
|
lock_page(page); |
|
WARN_ON(page_to_index(page) != index); |
|
wait_on_page_writeback(page); |
|
truncate_inode_page(mapping, page); |
|
unlock_page(page); |
|
} |
|
truncate_exceptional_pvec_entries(mapping, &pvec, indices); |
|
pagevec_release(&pvec); |
|
index++; |
|
} |
|
|
|
out: |
|
cleancache_invalidate_inode(mapping); |
|
} |
|
EXPORT_SYMBOL(truncate_inode_pages_range); |
|
|
|
/** |
|
* truncate_inode_pages - truncate *all* the pages from an offset |
|
* @mapping: mapping to truncate |
|
* @lstart: offset from which to truncate |
|
* |
|
* Called under (and serialised by) inode->i_mutex. |
|
* |
|
* Note: When this function returns, there can be a page in the process of |
|
* deletion (inside __delete_from_page_cache()) in the specified range. Thus |
|
* mapping->nrpages can be non-zero when this function returns even after |
|
* truncation of the whole mapping. |
|
*/ |
|
void truncate_inode_pages(struct address_space *mapping, loff_t lstart) |
|
{ |
|
truncate_inode_pages_range(mapping, lstart, (loff_t)-1); |
|
} |
|
EXPORT_SYMBOL(truncate_inode_pages); |
|
|
|
/** |
|
* truncate_inode_pages_final - truncate *all* pages before inode dies |
|
* @mapping: mapping to truncate |
|
* |
|
* Called under (and serialized by) inode->i_mutex. |
|
* |
|
* Filesystems have to use this in the .evict_inode path to inform the |
|
* VM that this is the final truncate and the inode is going away. |
|
*/ |
|
void truncate_inode_pages_final(struct address_space *mapping) |
|
{ |
|
unsigned long nrexceptional; |
|
unsigned long nrpages; |
|
|
|
/* |
|
* Page reclaim can not participate in regular inode lifetime |
|
* management (can't call iput()) and thus can race with the |
|
* inode teardown. Tell it when the address space is exiting, |
|
* so that it does not install eviction information after the |
|
* final truncate has begun. |
|
*/ |
|
mapping_set_exiting(mapping); |
|
|
|
/* |
|
* When reclaim installs eviction entries, it increases |
|
* nrexceptional first, then decreases nrpages. Make sure we see |
|
* this in the right order or we might miss an entry. |
|
*/ |
|
nrpages = mapping->nrpages; |
|
smp_rmb(); |
|
nrexceptional = mapping->nrexceptional; |
|
|
|
if (nrpages || nrexceptional) { |
|
/* |
|
* As truncation uses a lockless tree lookup, cycle |
|
* the tree lock to make sure any ongoing tree |
|
* modification that does not see AS_EXITING is |
|
* completed before starting the final truncate. |
|
*/ |
|
xa_lock_irq(&mapping->i_pages); |
|
xa_unlock_irq(&mapping->i_pages); |
|
} |
|
|
|
/* |
|
* Cleancache needs notification even if there are no pages or shadow |
|
* entries. |
|
*/ |
|
truncate_inode_pages(mapping, 0); |
|
} |
|
EXPORT_SYMBOL(truncate_inode_pages_final); |
|
|
|
static unsigned long __invalidate_mapping_pages(struct address_space *mapping, |
|
pgoff_t start, pgoff_t end, unsigned long *nr_pagevec) |
|
{ |
|
pgoff_t indices[PAGEVEC_SIZE]; |
|
struct pagevec pvec; |
|
pgoff_t index = start; |
|
unsigned long ret; |
|
unsigned long count = 0; |
|
int i; |
|
|
|
pagevec_init(&pvec); |
|
while (find_lock_entries(mapping, index, end, &pvec, indices)) { |
|
for (i = 0; i < pagevec_count(&pvec); i++) { |
|
struct page *page = pvec.pages[i]; |
|
|
|
/* We rely upon deletion not changing page->index */ |
|
index = indices[i]; |
|
|
|
if (xa_is_value(page)) { |
|
invalidate_exceptional_entry(mapping, index, |
|
page); |
|
continue; |
|
} |
|
index += thp_nr_pages(page) - 1; |
|
|
|
ret = invalidate_inode_page(page); |
|
unlock_page(page); |
|
/* |
|
* Invalidation is a hint that the page is no longer |
|
* of interest and try to speed up its reclaim. |
|
*/ |
|
if (!ret) { |
|
deactivate_file_page(page); |
|
/* It is likely on the pagevec of a remote CPU */ |
|
if (nr_pagevec) |
|
(*nr_pagevec)++; |
|
} |
|
count += ret; |
|
} |
|
pagevec_remove_exceptionals(&pvec); |
|
pagevec_release(&pvec); |
|
cond_resched(); |
|
index++; |
|
} |
|
return count; |
|
} |
|
|
|
/** |
|
* invalidate_mapping_pages - Invalidate all the unlocked pages of one inode |
|
* @mapping: the address_space which holds the pages to invalidate |
|
* @start: the offset 'from' which to invalidate |
|
* @end: the offset 'to' which to invalidate (inclusive) |
|
* |
|
* This function only removes the unlocked pages, if you want to |
|
* remove all the pages of one inode, you must call truncate_inode_pages. |
|
* |
|
* invalidate_mapping_pages() will not block on IO activity. It will not |
|
* invalidate pages which are dirty, locked, under writeback or mapped into |
|
* pagetables. |
|
* |
|
* Return: the number of the pages that were invalidated |
|
*/ |
|
unsigned long invalidate_mapping_pages(struct address_space *mapping, |
|
pgoff_t start, pgoff_t end) |
|
{ |
|
return __invalidate_mapping_pages(mapping, start, end, NULL); |
|
} |
|
EXPORT_SYMBOL(invalidate_mapping_pages); |
|
|
|
/** |
|
* invalidate_mapping_pagevec - Invalidate all the unlocked pages of one inode |
|
* @mapping: the address_space which holds the pages to invalidate |
|
* @start: the offset 'from' which to invalidate |
|
* @end: the offset 'to' which to invalidate (inclusive) |
|
* @nr_pagevec: invalidate failed page number for caller |
|
* |
|
* This helper is similar to invalidate_mapping_pages(), except that it accounts |
|
* for pages that are likely on a pagevec and counts them in @nr_pagevec, which |
|
* will be used by the caller. |
|
*/ |
|
void invalidate_mapping_pagevec(struct address_space *mapping, |
|
pgoff_t start, pgoff_t end, unsigned long *nr_pagevec) |
|
{ |
|
__invalidate_mapping_pages(mapping, start, end, nr_pagevec); |
|
} |
|
|
|
/* |
|
* This is like invalidate_complete_page(), except it ignores the page's |
|
* refcount. We do this because invalidate_inode_pages2() needs stronger |
|
* invalidation guarantees, and cannot afford to leave pages behind because |
|
* shrink_page_list() has a temp ref on them, or because they're transiently |
|
* sitting in the lru_cache_add() pagevecs. |
|
*/ |
|
static int |
|
invalidate_complete_page2(struct address_space *mapping, struct page *page) |
|
{ |
|
unsigned long flags; |
|
|
|
if (page->mapping != mapping) |
|
return 0; |
|
|
|
if (page_has_private(page) && !try_to_release_page(page, GFP_KERNEL)) |
|
return 0; |
|
|
|
xa_lock_irqsave(&mapping->i_pages, flags); |
|
if (PageDirty(page)) |
|
goto failed; |
|
|
|
BUG_ON(page_has_private(page)); |
|
__delete_from_page_cache(page, NULL); |
|
xa_unlock_irqrestore(&mapping->i_pages, flags); |
|
|
|
if (mapping->a_ops->freepage) |
|
mapping->a_ops->freepage(page); |
|
|
|
put_page(page); /* pagecache ref */ |
|
return 1; |
|
failed: |
|
xa_unlock_irqrestore(&mapping->i_pages, flags); |
|
return 0; |
|
} |
|
|
|
static int do_launder_page(struct address_space *mapping, struct page *page) |
|
{ |
|
if (!PageDirty(page)) |
|
return 0; |
|
if (page->mapping != mapping || mapping->a_ops->launder_page == NULL) |
|
return 0; |
|
return mapping->a_ops->launder_page(page); |
|
} |
|
|
|
/** |
|
* invalidate_inode_pages2_range - remove range of pages from an address_space |
|
* @mapping: the address_space |
|
* @start: the page offset 'from' which to invalidate |
|
* @end: the page offset 'to' which to invalidate (inclusive) |
|
* |
|
* Any pages which are found to be mapped into pagetables are unmapped prior to |
|
* invalidation. |
|
* |
|
* Return: -EBUSY if any pages could not be invalidated. |
|
*/ |
|
int invalidate_inode_pages2_range(struct address_space *mapping, |
|
pgoff_t start, pgoff_t end) |
|
{ |
|
pgoff_t indices[PAGEVEC_SIZE]; |
|
struct pagevec pvec; |
|
pgoff_t index; |
|
int i; |
|
int ret = 0; |
|
int ret2 = 0; |
|
int did_range_unmap = 0; |
|
|
|
if (mapping->nrpages == 0 && mapping->nrexceptional == 0) |
|
goto out; |
|
|
|
pagevec_init(&pvec); |
|
index = start; |
|
while (find_get_entries(mapping, index, end, &pvec, indices)) { |
|
for (i = 0; i < pagevec_count(&pvec); i++) { |
|
struct page *page = pvec.pages[i]; |
|
|
|
/* We rely upon deletion not changing page->index */ |
|
index = indices[i]; |
|
|
|
if (xa_is_value(page)) { |
|
if (!invalidate_exceptional_entry2(mapping, |
|
index, page)) |
|
ret = -EBUSY; |
|
continue; |
|
} |
|
|
|
lock_page(page); |
|
WARN_ON(page_to_index(page) != index); |
|
if (page->mapping != mapping) { |
|
unlock_page(page); |
|
continue; |
|
} |
|
wait_on_page_writeback(page); |
|
if (page_mapped(page)) { |
|
if (!did_range_unmap) { |
|
/* |
|
* Zap the rest of the file in one hit. |
|
*/ |
|
unmap_mapping_pages(mapping, index, |
|
(1 + end - index), false); |
|
did_range_unmap = 1; |
|
} else { |
|
/* |
|
* Just zap this page |
|
*/ |
|
unmap_mapping_pages(mapping, index, |
|
1, false); |
|
} |
|
} |
|
BUG_ON(page_mapped(page)); |
|
ret2 = do_launder_page(mapping, page); |
|
if (ret2 == 0) { |
|
if (!invalidate_complete_page2(mapping, page)) |
|
ret2 = -EBUSY; |
|
} |
|
if (ret2 < 0) |
|
ret = ret2; |
|
unlock_page(page); |
|
} |
|
pagevec_remove_exceptionals(&pvec); |
|
pagevec_release(&pvec); |
|
cond_resched(); |
|
index++; |
|
} |
|
/* |
|
* For DAX we invalidate page tables after invalidating page cache. We |
|
* could invalidate page tables while invalidating each entry however |
|
* that would be expensive. And doing range unmapping before doesn't |
|
* work as we have no cheap way to find whether page cache entry didn't |
|
* get remapped later. |
|
*/ |
|
if (dax_mapping(mapping)) { |
|
unmap_mapping_pages(mapping, start, end - start + 1, false); |
|
} |
|
out: |
|
cleancache_invalidate_inode(mapping); |
|
return ret; |
|
} |
|
EXPORT_SYMBOL_GPL(invalidate_inode_pages2_range); |
|
|
|
/** |
|
* invalidate_inode_pages2 - remove all pages from an address_space |
|
* @mapping: the address_space |
|
* |
|
* Any pages which are found to be mapped into pagetables are unmapped prior to |
|
* invalidation. |
|
* |
|
* Return: -EBUSY if any pages could not be invalidated. |
|
*/ |
|
int invalidate_inode_pages2(struct address_space *mapping) |
|
{ |
|
return invalidate_inode_pages2_range(mapping, 0, -1); |
|
} |
|
EXPORT_SYMBOL_GPL(invalidate_inode_pages2); |
|
|
|
/** |
|
* truncate_pagecache - unmap and remove pagecache that has been truncated |
|
* @inode: inode |
|
* @newsize: new file size |
|
* |
|
* inode's new i_size must already be written before truncate_pagecache |
|
* is called. |
|
* |
|
* This function should typically be called before the filesystem |
|
* releases resources associated with the freed range (eg. deallocates |
|
* blocks). This way, pagecache will always stay logically coherent |
|
* with on-disk format, and the filesystem would not have to deal with |
|
* situations such as writepage being called for a page that has already |
|
* had its underlying blocks deallocated. |
|
*/ |
|
void truncate_pagecache(struct inode *inode, loff_t newsize) |
|
{ |
|
struct address_space *mapping = inode->i_mapping; |
|
loff_t holebegin = round_up(newsize, PAGE_SIZE); |
|
|
|
/* |
|
* unmap_mapping_range is called twice, first simply for |
|
* efficiency so that truncate_inode_pages does fewer |
|
* single-page unmaps. However after this first call, and |
|
* before truncate_inode_pages finishes, it is possible for |
|
* private pages to be COWed, which remain after |
|
* truncate_inode_pages finishes, hence the second |
|
* unmap_mapping_range call must be made for correctness. |
|
*/ |
|
unmap_mapping_range(mapping, holebegin, 0, 1); |
|
truncate_inode_pages(mapping, newsize); |
|
unmap_mapping_range(mapping, holebegin, 0, 1); |
|
} |
|
EXPORT_SYMBOL(truncate_pagecache); |
|
|
|
/** |
|
* truncate_setsize - update inode and pagecache for a new file size |
|
* @inode: inode |
|
* @newsize: new file size |
|
* |
|
* truncate_setsize updates i_size and performs pagecache truncation (if |
|
* necessary) to @newsize. It will be typically be called from the filesystem's |
|
* setattr function when ATTR_SIZE is passed in. |
|
* |
|
* Must be called with a lock serializing truncates and writes (generally |
|
* i_mutex but e.g. xfs uses a different lock) and before all filesystem |
|
* specific block truncation has been performed. |
|
*/ |
|
void truncate_setsize(struct inode *inode, loff_t newsize) |
|
{ |
|
loff_t oldsize = inode->i_size; |
|
|
|
i_size_write(inode, newsize); |
|
if (newsize > oldsize) |
|
pagecache_isize_extended(inode, oldsize, newsize); |
|
truncate_pagecache(inode, newsize); |
|
} |
|
EXPORT_SYMBOL(truncate_setsize); |
|
|
|
/** |
|
* pagecache_isize_extended - update pagecache after extension of i_size |
|
* @inode: inode for which i_size was extended |
|
* @from: original inode size |
|
* @to: new inode size |
|
* |
|
* Handle extension of inode size either caused by extending truncate or by |
|
* write starting after current i_size. We mark the page straddling current |
|
* i_size RO so that page_mkwrite() is called on the nearest write access to |
|
* the page. This way filesystem can be sure that page_mkwrite() is called on |
|
* the page before user writes to the page via mmap after the i_size has been |
|
* changed. |
|
* |
|
* The function must be called after i_size is updated so that page fault |
|
* coming after we unlock the page will already see the new i_size. |
|
* The function must be called while we still hold i_mutex - this not only |
|
* makes sure i_size is stable but also that userspace cannot observe new |
|
* i_size value before we are prepared to store mmap writes at new inode size. |
|
*/ |
|
void pagecache_isize_extended(struct inode *inode, loff_t from, loff_t to) |
|
{ |
|
int bsize = i_blocksize(inode); |
|
loff_t rounded_from; |
|
struct page *page; |
|
pgoff_t index; |
|
|
|
WARN_ON(to > inode->i_size); |
|
|
|
if (from >= to || bsize == PAGE_SIZE) |
|
return; |
|
/* Page straddling @from will not have any hole block created? */ |
|
rounded_from = round_up(from, bsize); |
|
if (to <= rounded_from || !(rounded_from & (PAGE_SIZE - 1))) |
|
return; |
|
|
|
index = from >> PAGE_SHIFT; |
|
page = find_lock_page(inode->i_mapping, index); |
|
/* Page not cached? Nothing to do */ |
|
if (!page) |
|
return; |
|
/* |
|
* See clear_page_dirty_for_io() for details why set_page_dirty() |
|
* is needed. |
|
*/ |
|
if (page_mkclean(page)) |
|
set_page_dirty(page); |
|
unlock_page(page); |
|
put_page(page); |
|
} |
|
EXPORT_SYMBOL(pagecache_isize_extended); |
|
|
|
/** |
|
* truncate_pagecache_range - unmap and remove pagecache that is hole-punched |
|
* @inode: inode |
|
* @lstart: offset of beginning of hole |
|
* @lend: offset of last byte of hole |
|
* |
|
* This function should typically be called before the filesystem |
|
* releases resources associated with the freed range (eg. deallocates |
|
* blocks). This way, pagecache will always stay logically coherent |
|
* with on-disk format, and the filesystem would not have to deal with |
|
* situations such as writepage being called for a page that has already |
|
* had its underlying blocks deallocated. |
|
*/ |
|
void truncate_pagecache_range(struct inode *inode, loff_t lstart, loff_t lend) |
|
{ |
|
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; |
|
/* |
|
* This rounding is currently just for example: unmap_mapping_range |
|
* expands its hole outwards, whereas we want it to contract the hole |
|
* inwards. However, existing callers of truncate_pagecache_range are |
|
* doing their own page rounding first. Note that unmap_mapping_range |
|
* allows holelen 0 for all, and we allow lend -1 for end of file. |
|
*/ |
|
|
|
/* |
|
* Unlike in truncate_pagecache, unmap_mapping_range is called only |
|
* once (before truncating pagecache), and without "even_cows" flag: |
|
* hole-punching should not remove private COWed pages from the hole. |
|
*/ |
|
if ((u64)unmap_end > (u64)unmap_start) |
|
unmap_mapping_range(mapping, unmap_start, |
|
1 + unmap_end - unmap_start, 0); |
|
truncate_inode_pages_range(mapping, lstart, lend); |
|
} |
|
EXPORT_SYMBOL(truncate_pagecache_range);
|
|
|