On Sat, 2008-08-16 at 16:33 +0100, David Woodhouse wrote:
> Any particular reason why I shouldn't do this?
... and (something similar to) this...
diff --git a/include/linux/fadvise.h b/include/linux/fadvise.h
index e8e7471..344ab0e 100644
--- a/include/linux/fadvise.h
+++ b/include/linux/fadvise.h
@@ -18,4 +18,6 @@
#define POSIX_FADV_NOREUSE 5 /* Data will be accessed once. */
#endif
+#define LINUX_FADV_REMOVE 16 /* Discard data permanently */
+
#endif /* FADVISE_H_INCLUDED */
diff --git a/mm/fadvise.c b/mm/fadvise.c
index 343cfdf..c2e1baf 100644
--- a/mm/fadvise.c
+++ b/mm/fadvise.c
@@ -57,6 +57,7 @@ asmlinkage long sys_fadvise64_64(int fd, loff_t offset, loff_t len, int advice)
case POSIX_FADV_WILLNEED:
case POSIX_FADV_NOREUSE:
case POSIX_FADV_DONTNEED:
+ case LINUX_FADV_REMOVE:
/* no bad return value, but ignore advice */
break;
default:
@@ -119,6 +120,29 @@ asmlinkage long sys_fadvise64_64(int fd, loff_t offset, loff_t len, int advice)
invalidate_mapping_pages(mapping, start_index,
end_index);
break;
+ case LINUX_FADV_REMOVE:
+ if (!(file->f_mode & FMODE_WRITE)) {
+ ret = -EBADF;
+ goto out;
+ }
+ if ((offset & ~PAGE_MASK) || (len & ~PAGE_MASK)) {
+ /* truncate_inode_pages_range() can't cope */
+ ret = -EINVAL;
+ goto out;
+ }
+ if (endbyte == -1) {
+ /* FIXME: truncate to end */
+ ret = -EINVAL;
+ goto out;
+ }
+
+ if (!mapping->host || !mapping->host->i_op ||
+ !mapping->host->i_op->truncate_range) {
+ ret = -EINVAL;
+ goto out;
+ }
+ vmtruncate_range(mapping->host, offset, endbyte);
+ break;
default:
ret = -EINVAL;
}
--
David Woodhouse Open Source Technology Centre
David.Woodhouse@xxxxxxxxx Intel Corporation
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