X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=mm%2Ffilemap.c;h=126d3973b3d1f3be7a3f5e4f42630725c796f31f;hb=e2f17d9459aeccf4e013e31cbd741d6b1858eec4;hp=2ed8b0389c51a91d7dbc24fa210310d3986ca5fe;hpb=19fd6231279be3c3bdd02ed99f9b0eb195978064;p=safe%2Fjmp%2Flinux-2.6 diff --git a/mm/filemap.c b/mm/filemap.c index 2ed8b03..126d397 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -33,6 +33,7 @@ #include #include /* for BUG_ON(!in_atomic()) only */ #include +#include /* for page_is_file_cache() */ #include "internal.h" /* @@ -115,12 +116,12 @@ void __remove_from_page_cache(struct page *page) { struct address_space *mapping = page->mapping; - mem_cgroup_uncharge_cache_page(page); radix_tree_delete(&mapping->page_tree, page->index); page->mapping = NULL; mapping->nrpages--; __dec_zone_page_state(page, NR_FILE_PAGES); BUG_ON(page_mapped(page)); + mem_cgroup_uncharge_cache_page(page); /* * Some filesystems seem to re-dirty the page even after @@ -209,7 +210,7 @@ int __filemap_fdatawrite_range(struct address_space *mapping, loff_t start, int ret; struct writeback_control wbc = { .sync_mode = sync_mode, - .nr_to_write = mapping->nrpages * 2, + .nr_to_write = LONG_MAX, .range_start = start, .range_end = end, }; @@ -459,7 +460,7 @@ int add_to_page_cache_locked(struct page *page, struct address_space *mapping, VM_BUG_ON(!PageLocked(page)); error = mem_cgroup_cache_charge(page, current->mm, - gfp_mask & ~__GFP_HIGHMEM); + gfp_mask & GFP_RECLAIM_MASK); if (error) goto out; @@ -492,9 +493,24 @@ EXPORT_SYMBOL(add_to_page_cache_locked); int add_to_page_cache_lru(struct page *page, struct address_space *mapping, pgoff_t offset, gfp_t gfp_mask) { - int ret = add_to_page_cache(page, mapping, offset, gfp_mask); - if (ret == 0) - lru_cache_add(page); + int ret; + + /* + * Splice_read and readahead add shmem/tmpfs pages into the page cache + * before shmem_readpage has a chance to mark them as SwapBacked: they + * need to go on the active_anon lru below, and mem_cgroup_cache_charge + * (called in add_to_page_cache) needs to know where they're going too. + */ + if (mapping_cap_swap_backed(mapping)) + SetPageSwapBacked(page); + + ret = add_to_page_cache(page, mapping, offset, gfp_mask); + if (ret == 0) { + if (page_is_file_cache(page)) + lru_cache_add_file(page); + else + lru_cache_add_active_anon(page); + } return ret; } @@ -557,17 +573,14 @@ EXPORT_SYMBOL(wait_on_page_bit); * mechananism between PageLocked pages and PageWriteback pages is shared. * But that's OK - sleepers in wait_on_page_writeback() just go back to sleep. * - * The first mb is necessary to safely close the critical section opened by the - * TestSetPageLocked(), the second mb is necessary to enforce ordering between - * the clear_bit and the read of the waitqueue (to avoid SMP races with a - * parallel wait_on_page_locked()). + * The mb is necessary to enforce ordering between the clear_bit and the read + * of the waitqueue (to avoid SMP races with a parallel wait_on_page_locked()). */ void unlock_page(struct page *page) { - smp_mb__before_clear_bit(); - if (!TestClearPageLocked(page)) - BUG(); - smp_mb__after_clear_bit(); + VM_BUG_ON(!PageLocked(page)); + clear_bit_unlock(PG_locked, &page->flags); + smp_mb__after_clear_bit(); wake_up_page(page, PG_locked); } EXPORT_SYMBOL(unlock_page); @@ -728,7 +741,14 @@ repeat: page = __page_cache_alloc(gfp_mask); if (!page) return NULL; - err = add_to_page_cache_lru(page, mapping, index, gfp_mask); + /* + * We want a regular kernel memory (not highmem or DMA etc) + * allocation for the radix tree nodes, but we need to honour + * the context-specific requirements the caller has asked for. + * GFP_RECLAIM_MASK collects those requirements. + */ + err = add_to_page_cache_lru(page, mapping, index, + (gfp_mask & GFP_RECLAIM_MASK)); if (unlikely(err)) { page_cache_release(page); page = NULL; @@ -931,13 +951,13 @@ grab_cache_page_nowait(struct address_space *mapping, pgoff_t index) struct page *page = find_get_page(mapping, index); if (page) { - if (!TestSetPageLocked(page)) + if (trylock_page(page)) return page; page_cache_release(page); return NULL; } page = __page_cache_alloc(mapping_gfp_mask(mapping) & ~__GFP_FS); - if (page && add_to_page_cache_lru(page, mapping, index, GFP_KERNEL)) { + if (page && add_to_page_cache_lru(page, mapping, index, GFP_NOFS)) { page_cache_release(page); page = NULL; } @@ -1023,8 +1043,17 @@ find_page: ra, filp, page, index, last_index - index); } - if (!PageUptodate(page)) - goto page_not_up_to_date; + if (!PageUptodate(page)) { + if (inode->i_blkbits == PAGE_CACHE_SHIFT || + !mapping->a_ops->is_partially_uptodate) + goto page_not_up_to_date; + if (!trylock_page(page)) + goto page_not_up_to_date; + if (!mapping->a_ops->is_partially_uptodate(page, + desc, offset)) + goto page_not_up_to_date_locked; + unlock_page(page); + } page_ok: /* * i_size must be checked after we know the page is Uptodate. @@ -1091,9 +1120,11 @@ page_ok: page_not_up_to_date: /* Get exclusive access to the page ... */ - if (lock_page_killable(page)) - goto readpage_eio; + error = lock_page_killable(page); + if (unlikely(error)) + goto readpage_error; +page_not_up_to_date_locked: /* Did it get truncated before we got the lock? */ if (!page->mapping) { unlock_page(page); @@ -1120,8 +1151,9 @@ readpage: } if (!PageUptodate(page)) { - if (lock_page_killable(page)) - goto readpage_eio; + error = lock_page_killable(page); + if (unlikely(error)) + goto readpage_error; if (!PageUptodate(page)) { if (page->mapping == NULL) { /* @@ -1133,15 +1165,14 @@ readpage: } unlock_page(page); shrink_readahead_size_eio(filp, ra); - goto readpage_eio; + error = -EIO; + goto readpage_error; } unlock_page(page); } goto page_ok; -readpage_eio: - error = -EIO; readpage_error: /* UHHUH! A synchronous read error occurred. Report it */ desc->error = error; @@ -1176,8 +1207,7 @@ out: ra->prev_pos |= prev_offset; *ppos = ((loff_t)index << PAGE_CACHE_SHIFT) + offset; - if (filp) - file_accessed(filp); + file_accessed(filp); } int file_read_actor(read_descriptor_t *desc, struct page *page, @@ -1294,7 +1324,8 @@ generic_file_aio_read(struct kiocb *iocb, const struct iovec *iov, goto out; /* skip atime */ size = i_size_read(inode); if (pos < size) { - retval = filemap_write_and_wait(mapping); + retval = filemap_write_and_wait_range(mapping, pos, + pos + iov_length(iov, nr_segs) - 1); if (!retval) { retval = mapping->a_ops->direct_IO(READ, iocb, iov, pos, nr_segs); @@ -1343,7 +1374,7 @@ do_readahead(struct address_space *mapping, struct file *filp, return 0; } -asmlinkage ssize_t sys_readahead(int fd, loff_t offset, size_t count) +SYSCALL_DEFINE(readahead)(int fd, loff_t offset, size_t count) { ssize_t ret; struct file *file; @@ -1362,6 +1393,13 @@ asmlinkage ssize_t sys_readahead(int fd, loff_t offset, size_t count) } return ret; } +#ifdef CONFIG_HAVE_SYSCALL_WRAPPERS +asmlinkage long SyS_readahead(long fd, loff_t offset, long count) +{ + return SYSC_readahead((int) fd, offset, (size_t) count); +} +SYSCALL_ALIAS(sys_readahead, SyS_readahead); +#endif #ifdef CONFIG_MMU /** @@ -1507,7 +1545,6 @@ retry_find: /* * Found the page and have a reference on it. */ - mark_page_accessed(page); ra->prev_pos = (loff_t)page->index << PAGE_CACHE_SHIFT; vmf->page = page; return ret | VM_FAULT_LOCKED; @@ -1743,7 +1780,7 @@ int should_remove_suid(struct dentry *dentry) if (unlikely((mode & S_ISGID) && (mode & S_IXGRP))) kill |= ATTR_KILL_SGID; - if (unlikely(kill && !capable(CAP_FSETID))) + if (unlikely(kill && !capable(CAP_FSETID) && S_ISREG(mode))) return kill; return 0; @@ -1758,8 +1795,9 @@ static int __remove_suid(struct dentry *dentry, int kill) return notify_change(dentry, &newattrs); } -int remove_suid(struct dentry *dentry) +int file_remove_suid(struct file *file) { + struct dentry *dentry = file->f_path.dentry; int killsuid = should_remove_suid(dentry); int killpriv = security_inode_need_killpriv(dentry); int error = 0; @@ -1773,7 +1811,7 @@ int remove_suid(struct dentry *dentry) return error; } -EXPORT_SYMBOL(remove_suid); +EXPORT_SYMBOL(file_remove_suid); static size_t __iovec_copy_from_user_inatomic(char *vaddr, const struct iovec *iov, size_t base, size_t bytes) @@ -1785,7 +1823,7 @@ static size_t __iovec_copy_from_user_inatomic(char *vaddr, int copy = min(bytes, iov->iov_len - base); base = 0; - left = __copy_from_user_inatomic_nocache(vaddr, buf, copy); + left = __copy_from_user_inatomic(vaddr, buf, copy); copied += copy; bytes -= copy; vaddr += copy; @@ -1813,8 +1851,7 @@ size_t iov_iter_copy_from_user_atomic(struct page *page, if (likely(i->nr_segs == 1)) { int left; char __user *buf = i->iov->iov_base + i->iov_offset; - left = __copy_from_user_inatomic_nocache(kaddr + offset, - buf, bytes); + left = __copy_from_user_inatomic(kaddr + offset, buf, bytes); copied = bytes - left; } else { copied = __iovec_copy_from_user_inatomic(kaddr + offset, @@ -1842,7 +1879,7 @@ size_t iov_iter_copy_from_user(struct page *page, if (likely(i->nr_segs == 1)) { int left; char __user *buf = i->iov->iov_base + i->iov_offset; - left = __copy_from_user_nocache(kaddr + offset, buf, bytes); + left = __copy_from_user(kaddr + offset, buf, bytes); copied = bytes - left; } else { copied = __iovec_copy_from_user_inatomic(kaddr + offset, @@ -1868,7 +1905,7 @@ void iov_iter_advance(struct iov_iter *i, size_t bytes) * The !iov->iov_len check ensures we skip over unlikely * zero-length segments (without overruning the iovec). */ - while (bytes || unlikely(!iov->iov_len && i->count)) { + while (bytes || unlikely(i->count && !iov->iov_len)) { int copy; copy = min(bytes, iov->iov_len - base); @@ -2005,48 +2042,8 @@ int pagecache_write_begin(struct file *file, struct address_space *mapping, { const struct address_space_operations *aops = mapping->a_ops; - if (aops->write_begin) { - return aops->write_begin(file, mapping, pos, len, flags, + return aops->write_begin(file, mapping, pos, len, flags, pagep, fsdata); - } else { - int ret; - pgoff_t index = pos >> PAGE_CACHE_SHIFT; - unsigned offset = pos & (PAGE_CACHE_SIZE - 1); - struct inode *inode = mapping->host; - struct page *page; -again: - page = __grab_cache_page(mapping, index); - *pagep = page; - if (!page) - return -ENOMEM; - - if (flags & AOP_FLAG_UNINTERRUPTIBLE && !PageUptodate(page)) { - /* - * There is no way to resolve a short write situation - * for a !Uptodate page (except by double copying in - * the caller done by generic_perform_write_2copy). - * - * Instead, we have to bring it uptodate here. - */ - ret = aops->readpage(file, page); - page_cache_release(page); - if (ret) { - if (ret == AOP_TRUNCATED_PAGE) - goto again; - return ret; - } - goto again; - } - - ret = aops->prepare_write(file, page, offset, offset+len); - if (ret) { - unlock_page(page); - page_cache_release(page); - if (pos + len > inode->i_size) - vmtruncate(inode, inode->i_size); - } - return ret; - } } EXPORT_SYMBOL(pagecache_write_begin); @@ -2055,32 +2052,9 @@ int pagecache_write_end(struct file *file, struct address_space *mapping, struct page *page, void *fsdata) { const struct address_space_operations *aops = mapping->a_ops; - int ret; - - if (aops->write_end) { - mark_page_accessed(page); - ret = aops->write_end(file, mapping, pos, len, copied, - page, fsdata); - } else { - unsigned offset = pos & (PAGE_CACHE_SIZE - 1); - struct inode *inode = mapping->host; - - flush_dcache_page(page); - ret = aops->commit_write(file, page, offset, offset+len); - unlock_page(page); - mark_page_accessed(page); - page_cache_release(page); - if (ret < 0) { - if (pos + len > inode->i_size) - vmtruncate(inode, inode->i_size); - } else if (ret > 0) - ret = min_t(size_t, copied, ret); - else - ret = copied; - } - - return ret; + mark_page_accessed(page); + return aops->write_end(file, mapping, pos, len, copied, page, fsdata); } EXPORT_SYMBOL(pagecache_write_end); @@ -2099,18 +2073,10 @@ generic_file_direct_write(struct kiocb *iocb, const struct iovec *iov, if (count != ocount) *nr_segs = iov_shorten((struct iovec *)iov, *nr_segs, count); - /* - * Unmap all mmappings of the file up-front. - * - * This will cause any pte dirty bits to be propagated into the - * pageframes for the subsequent filemap_write_and_wait(). - */ write_len = iov_length(iov, *nr_segs); end = (pos + write_len - 1) >> PAGE_CACHE_SHIFT; - if (mapping_mapped(mapping)) - unmap_mapping_range(mapping, pos, write_len, 0); - written = filemap_write_and_wait(mapping); + written = filemap_write_and_wait_range(mapping, pos, pos + write_len - 1); if (written) goto out; @@ -2118,13 +2084,20 @@ generic_file_direct_write(struct kiocb *iocb, const struct iovec *iov, * After a write we want buffered reads to be sure to go to disk to get * the new data. We invalidate clean cached page from the region we're * about to write. We do this *before* the write so that we can return - * -EIO without clobbering -EIOCBQUEUED from ->direct_IO(). + * without clobbering -EIOCBQUEUED from ->direct_IO(). */ if (mapping->nrpages) { written = invalidate_inode_pages2_range(mapping, pos >> PAGE_CACHE_SHIFT, end); - if (written) + /* + * If a page can not be invalidated, return 0 to fall back + * to buffered write. + */ + if (written) { + if (written == -EBUSY) + return 0; goto out; + } } written = mapping->a_ops->direct_IO(WRITE, iocb, iov, pos, *nr_segs); @@ -2172,19 +2145,24 @@ EXPORT_SYMBOL(generic_file_direct_write); * Find or create a page at the given pagecache position. Return the locked * page. This function is specifically for buffered writes. */ -struct page *__grab_cache_page(struct address_space *mapping, pgoff_t index) +struct page *grab_cache_page_write_begin(struct address_space *mapping, + pgoff_t index, unsigned flags) { int status; struct page *page; + gfp_t gfp_notmask = 0; + if (flags & AOP_FLAG_NOFS) + gfp_notmask = __GFP_FS; repeat: page = find_lock_page(mapping, index); if (likely(page)) return page; - page = page_cache_alloc(mapping); + page = __page_cache_alloc(mapping_gfp_mask(mapping) & ~gfp_notmask); if (!page) return NULL; - status = add_to_page_cache_lru(page, mapping, index, GFP_KERNEL); + status = add_to_page_cache_lru(page, mapping, index, + GFP_KERNEL & ~gfp_notmask); if (unlikely(status)) { page_cache_release(page); if (status == -EEXIST) @@ -2193,175 +2171,7 @@ repeat: } return page; } -EXPORT_SYMBOL(__grab_cache_page); - -static ssize_t generic_perform_write_2copy(struct file *file, - struct iov_iter *i, loff_t pos) -{ - struct address_space *mapping = file->f_mapping; - const struct address_space_operations *a_ops = mapping->a_ops; - struct inode *inode = mapping->host; - long status = 0; - ssize_t written = 0; - - do { - struct page *src_page; - struct page *page; - pgoff_t index; /* Pagecache index for current page */ - unsigned long offset; /* Offset into pagecache page */ - unsigned long bytes; /* Bytes to write to page */ - size_t copied; /* Bytes copied from user */ - - offset = (pos & (PAGE_CACHE_SIZE - 1)); - index = pos >> PAGE_CACHE_SHIFT; - bytes = min_t(unsigned long, PAGE_CACHE_SIZE - offset, - iov_iter_count(i)); - - /* - * a non-NULL src_page indicates that we're doing the - * copy via get_user_pages and kmap. - */ - src_page = NULL; - - /* - * Bring in the user page that we will copy from _first_. - * Otherwise there's a nasty deadlock on copying from the - * same page as we're writing to, without it being marked - * up-to-date. - * - * Not only is this an optimisation, but it is also required - * to check that the address is actually valid, when atomic - * usercopies are used, below. - */ - if (unlikely(iov_iter_fault_in_readable(i, bytes))) { - status = -EFAULT; - break; - } - - page = __grab_cache_page(mapping, index); - if (!page) { - status = -ENOMEM; - break; - } - - /* - * non-uptodate pages cannot cope with short copies, and we - * cannot take a pagefault with the destination page locked. - * So pin the source page to copy it. - */ - if (!PageUptodate(page) && !segment_eq(get_fs(), KERNEL_DS)) { - unlock_page(page); - - src_page = alloc_page(GFP_KERNEL); - if (!src_page) { - page_cache_release(page); - status = -ENOMEM; - break; - } - - /* - * Cannot get_user_pages with a page locked for the - * same reason as we can't take a page fault with a - * page locked (as explained below). - */ - copied = iov_iter_copy_from_user(src_page, i, - offset, bytes); - if (unlikely(copied == 0)) { - status = -EFAULT; - page_cache_release(page); - page_cache_release(src_page); - break; - } - bytes = copied; - - lock_page(page); - /* - * Can't handle the page going uptodate here, because - * that means we would use non-atomic usercopies, which - * zero out the tail of the page, which can cause - * zeroes to become transiently visible. We could just - * use a non-zeroing copy, but the APIs aren't too - * consistent. - */ - if (unlikely(!page->mapping || PageUptodate(page))) { - unlock_page(page); - page_cache_release(page); - page_cache_release(src_page); - continue; - } - } - - status = a_ops->prepare_write(file, page, offset, offset+bytes); - if (unlikely(status)) - goto fs_write_aop_error; - - if (!src_page) { - /* - * Must not enter the pagefault handler here, because - * we hold the page lock, so we might recursively - * deadlock on the same lock, or get an ABBA deadlock - * against a different lock, or against the mmap_sem - * (which nests outside the page lock). So increment - * preempt count, and use _atomic usercopies. - * - * The page is uptodate so we are OK to encounter a - * short copy: if unmodified parts of the page are - * marked dirty and written out to disk, it doesn't - * really matter. - */ - pagefault_disable(); - copied = iov_iter_copy_from_user_atomic(page, i, - offset, bytes); - pagefault_enable(); - } else { - void *src, *dst; - src = kmap_atomic(src_page, KM_USER0); - dst = kmap_atomic(page, KM_USER1); - memcpy(dst + offset, src + offset, bytes); - kunmap_atomic(dst, KM_USER1); - kunmap_atomic(src, KM_USER0); - copied = bytes; - } - flush_dcache_page(page); - - status = a_ops->commit_write(file, page, offset, offset+bytes); - if (unlikely(status < 0)) - goto fs_write_aop_error; - if (unlikely(status > 0)) /* filesystem did partial write */ - copied = min_t(size_t, copied, status); - - unlock_page(page); - mark_page_accessed(page); - page_cache_release(page); - if (src_page) - page_cache_release(src_page); - - iov_iter_advance(i, copied); - pos += copied; - written += copied; - - balance_dirty_pages_ratelimited(mapping); - cond_resched(); - continue; - -fs_write_aop_error: - unlock_page(page); - page_cache_release(page); - if (src_page) - page_cache_release(src_page); - - /* - * prepare_write() may have instantiated a few blocks - * outside i_size. Trim these off again. Don't need - * i_size_read because we hold i_mutex. - */ - if (pos + bytes > inode->i_size) - vmtruncate(inode, inode->i_size); - break; - } while (iov_iter_count(i)); - - return written ? written : status; -} +EXPORT_SYMBOL(grab_cache_page_write_begin); static ssize_t generic_perform_write(struct file *file, struct iov_iter *i, loff_t pos) @@ -2463,10 +2273,7 @@ generic_file_buffered_write(struct kiocb *iocb, const struct iovec *iov, struct iov_iter i; iov_iter_init(&i, iov, nr_segs, count, written); - if (a_ops->write_begin) - status = generic_perform_write(file, &i, pos); - else - status = generic_perform_write_2copy(file, &i, pos); + status = generic_perform_write(file, &i, pos); if (likely(status >= 0)) { written += status; @@ -2489,7 +2296,8 @@ generic_file_buffered_write(struct kiocb *iocb, const struct iovec *iov, * the file data here, to try to honour O_DIRECT expectations. */ if (unlikely(file->f_flags & O_DIRECT) && written) - status = filemap_write_and_wait(mapping); + status = filemap_write_and_wait_range(mapping, + pos, pos + written - 1); return written ? written : status; } @@ -2529,7 +2337,7 @@ __generic_file_aio_write_nolock(struct kiocb *iocb, const struct iovec *iov, if (count == 0) goto out; - err = remove_suid(file->f_path.dentry); + err = file_remove_suid(file); if (err) goto out;