diff options
Diffstat (limited to 'mm/fadvise.c')
| -rw-r--r-- | mm/fadvise.c | 46 |
1 files changed, 41 insertions, 5 deletions
diff --git a/mm/fadvise.c b/mm/fadvise.c index d257c89..907c392 100644 --- a/mm/fadvise.c +++ b/mm/fadvise.c @@ -15,6 +15,7 @@ #include <linux/backing-dev.h> #include <linux/pagevec.h> #include <linux/fadvise.h> +#include <linux/writeback.h> #include <linux/syscalls.h> #include <asm/unistd.h> @@ -22,13 +23,36 @@ /* * POSIX_FADV_WILLNEED could set PG_Referenced, and POSIX_FADV_NOREUSE could * deactivate the pages and clear PG_Referenced. + * + * LINUX_FADV_ASYNC_WRITE: start async writeout of any dirty pages between file + * offsets `offset' and `offset+len' inclusive. Any pages which are currently + * under writeout are skipped, whether or not they are dirty. + * + * LINUX_FADV_WRITE_WAIT: wait upon writeout of any dirty pages between file + * offsets `offset' and `offset+len'. + * + * By combining these two operations the application may do several things: + * + * LINUX_FADV_ASYNC_WRITE: push some or all of the dirty pages at the disk. + * + * LINUX_FADV_WRITE_WAIT, LINUX_FADV_ASYNC_WRITE: push all of the currently + * dirty pages at the disk. + * + * LINUX_FADV_WRITE_WAIT, LINUX_FADV_ASYNC_WRITE, LINUX_FADV_WRITE_WAIT: push + * all of the currently dirty pages at the disk, wait until they have been + * written. + * + * It should be noted that none of these operations write out the file's + * metadata. So unless the application is strictly performing overwrites of + * already-instantiated disk blocks, there are no guarantees here that the data + * will be available after a crash. */ asmlinkage long sys_fadvise64_64(int fd, loff_t offset, loff_t len, int advice) { struct file *file = fget(fd); struct address_space *mapping; struct backing_dev_info *bdi; - loff_t endbyte; + loff_t endbyte; /* inclusive */ pgoff_t start_index; pgoff_t end_index; unsigned long nrpages; @@ -56,6 +80,8 @@ asmlinkage long sys_fadvise64_64(int fd, loff_t offset, loff_t len, int advice) endbyte = offset + len; if (!len || endbyte < len) endbyte = -1; + else + endbyte--; /* inclusive */ bdi = mapping->backing_dev_info; @@ -78,7 +104,7 @@ asmlinkage long sys_fadvise64_64(int fd, loff_t offset, loff_t len, int advice) /* First and last PARTIAL page! */ start_index = offset >> PAGE_CACHE_SHIFT; - end_index = (endbyte-1) >> PAGE_CACHE_SHIFT; + end_index = endbyte >> PAGE_CACHE_SHIFT; /* Careful about overflow on the "+1" */ nrpages = end_index - start_index + 1; @@ -96,11 +122,21 @@ asmlinkage long sys_fadvise64_64(int fd, loff_t offset, loff_t len, int advice) filemap_flush(mapping); /* First and last FULL page! */ - start_index = (offset + (PAGE_CACHE_SIZE-1)) >> PAGE_CACHE_SHIFT; + start_index = (offset+(PAGE_CACHE_SIZE-1)) >> PAGE_CACHE_SHIFT; end_index = (endbyte >> PAGE_CACHE_SHIFT); - if (end_index > start_index) - invalidate_mapping_pages(mapping, start_index, end_index-1); + if (end_index >= start_index) + invalidate_mapping_pages(mapping, start_index, + end_index); + break; + case LINUX_FADV_ASYNC_WRITE: + ret = __filemap_fdatawrite_range(mapping, offset, endbyte, + WB_SYNC_NONE); + break; + case LINUX_FADV_WRITE_WAIT: + ret = wait_on_page_writeback_range(mapping, + offset >> PAGE_CACHE_SHIFT, + endbyte >> PAGE_CACHE_SHIFT); break; default: ret = -EINVAL; |
