25 files changed, 105 insertions, 9 deletions

diff --git a/include/asm-alpha/mman.h b/include/asm-alpha/mman.h
index eb9c279..f643953 100644
--- a/include/asm-alpha/mman.h
+++ b/include/asm-alpha/mman.h
@@ -42,6 +42,7 @@
 #define MADV_WILLNEED	3		/* will need these pages */
 #define	MADV_SPACEAVAIL	5		/* ensure resources are available */
 #define MADV_DONTNEED	6		/* don't need these pages */
+#define MADV_REMOVE	7		/* remove these pages & resources */
 
 /* compatibility flags */
 #define MAP_ANON	MAP_ANONYMOUS
diff --git a/include/asm-arm/mman.h b/include/asm-arm/mman.h
index 8e4f69c..f0bebca 100644
--- a/include/asm-arm/mman.h
+++ b/include/asm-arm/mman.h
@@ -35,6 +35,7 @@
 #define MADV_SEQUENTIAL	0x2		/* read-ahead aggressively */
 #define MADV_WILLNEED	0x3		/* pre-fault pages */
 #define MADV_DONTNEED	0x4		/* discard these pages */
+#define MADV_REMOVE	0x5		/* remove these pages & resources */
 
 /* compatibility flags */
 #define MAP_ANON	MAP_ANONYMOUS
diff --git a/include/asm-arm26/mman.h b/include/asm-arm26/mman.h
index cc27b82..0ed7780 100644
--- a/include/asm-arm26/mman.h
+++ b/include/asm-arm26/mman.h
@@ -35,6 +35,7 @@
 #define MADV_SEQUENTIAL	0x2		/* read-ahead aggressively */
 #define MADV_WILLNEED	0x3		/* pre-fault pages */
 #define MADV_DONTNEED	0x4		/* discard these pages */
+#define MADV_REMOVE	0x5		/* remove these pages & resources */
 
 /* compatibility flags */
 #define MAP_ANON	MAP_ANONYMOUS
diff --git a/include/asm-cris/mman.h b/include/asm-cris/mman.h
index 8570e72..5a382b8 100644
--- a/include/asm-cris/mman.h
+++ b/include/asm-cris/mman.h
@@ -37,6 +37,7 @@
 #define MADV_SEQUENTIAL	0x2		/* read-ahead aggressively */
 #define MADV_WILLNEED	0x3		/* pre-fault pages */
 #define MADV_DONTNEED	0x4		/* discard these pages */
+#define MADV_REMOVE	0x5		/* remove these pages & resources */
 
 /* compatibility flags */
 #define MAP_ANON	MAP_ANONYMOUS
diff --git a/include/asm-frv/mman.h b/include/asm-frv/mman.h
index c684720..8af4a41 100644
--- a/include/asm-frv/mman.h
+++ b/include/asm-frv/mman.h
@@ -35,6 +35,7 @@
 #define MADV_SEQUENTIAL	0x2		/* read-ahead aggressively */
 #define MADV_WILLNEED	0x3		/* pre-fault pages */
 #define MADV_DONTNEED	0x4		/* discard these pages */
+#define MADV_REMOVE	0x5		/* remove these pages & resources */
 
 /* compatibility flags */
 #define MAP_ANON	MAP_ANONYMOUS
diff --git a/include/asm-h8300/mman.h b/include/asm-h8300/mman.h
index 63f727a..744a8fb 100644
--- a/include/asm-h8300/mman.h
+++ b/include/asm-h8300/mman.h
@@ -35,6 +35,7 @@
 #define MADV_SEQUENTIAL	0x2		/* read-ahead aggressively */
 #define MADV_WILLNEED	0x3		/* pre-fault pages */
 #define MADV_DONTNEED	0x4		/* discard these pages */
+#define MADV_REMOVE	0x5		/* remove these pages & resources */
 
 /* compatibility flags */
 #define MAP_ANON	MAP_ANONYMOUS
diff --git a/include/asm-i386/mman.h b/include/asm-i386/mman.h
index 196619a..ba4941e 100644
--- a/include/asm-i386/mman.h
+++ b/include/asm-i386/mman.h
@@ -35,6 +35,7 @@
 #define MADV_SEQUENTIAL	0x2		/* read-ahead aggressively */
 #define MADV_WILLNEED	0x3		/* pre-fault pages */
 #define MADV_DONTNEED	0x4		/* discard these pages */
+#define MADV_REMOVE	0x5		/* remove these pages & resources */
 
 /* compatibility flags */
 #define MAP_ANON	MAP_ANONYMOUS
diff --git a/include/asm-ia64/mman.h b/include/asm-ia64/mman.h
index 1c0a73a..828beb2 100644
--- a/include/asm-ia64/mman.h
+++ b/include/asm-ia64/mman.h
@@ -43,6 +43,7 @@
 #define MADV_SEQUENTIAL	0x2		/* read-ahead aggressively */
 #define MADV_WILLNEED	0x3		/* pre-fault pages */
 #define MADV_DONTNEED	0x4		/* discard these pages */
+#define MADV_REMOVE	0x5		/* remove these pages & resources */
 
 /* compatibility flags */
 #define MAP_ANON	MAP_ANONYMOUS
diff --git a/include/asm-m32r/mman.h b/include/asm-m32r/mman.h
index 011f6d9..12e2974 100644
--- a/include/asm-m32r/mman.h
+++ b/include/asm-m32r/mman.h
@@ -37,6 +37,7 @@
 #define MADV_SEQUENTIAL	0x2		/* read-ahead aggressively */
 #define MADV_WILLNEED	0x3		/* pre-fault pages */
 #define MADV_DONTNEED	0x4		/* discard these pages */
+#define MADV_REMOVE	0x5		/* remove these pages & resources */
 
 /* compatibility flags */
 #define MAP_ANON	MAP_ANONYMOUS
diff --git a/include/asm-m68k/mman.h b/include/asm-m68k/mman.h
index f831c4e..ea262ab 100644
--- a/include/asm-m68k/mman.h
+++ b/include/asm-m68k/mman.h
@@ -35,6 +35,7 @@
 #define MADV_SEQUENTIAL	0x2		/* read-ahead aggressively */
 #define MADV_WILLNEED	0x3		/* pre-fault pages */
 #define MADV_DONTNEED	0x4		/* discard these pages */
+#define MADV_REMOVE	0x5		/* remove these pages & resources */
 
 /* compatibility flags */
 #define MAP_ANON	MAP_ANONYMOUS
diff --git a/include/asm-mips/mman.h b/include/asm-mips/mman.h
index 6206095..dd17c8b 100644
--- a/include/asm-mips/mman.h
+++ b/include/asm-mips/mman.h
@@ -65,6 +65,7 @@
 #define MADV_SEQUENTIAL	0x2		/* read-ahead aggressively */
 #define MADV_WILLNEED	0x3		/* pre-fault pages */
 #define MADV_DONTNEED	0x4		/* discard these pages */
+#define MADV_REMOVE	0x5		/* remove these pages & resources */
 
 /* compatibility flags */
 #define MAP_ANON       MAP_ANONYMOUS
diff --git a/include/asm-parisc/mman.h b/include/asm-parisc/mman.h
index e829607..736b0ab 100644
--- a/include/asm-parisc/mman.h
+++ b/include/asm-parisc/mman.h
@@ -38,6 +38,7 @@
 #define MADV_SPACEAVAIL 5               /* insure that resources are reserved */
 #define MADV_VPS_PURGE  6               /* Purge pages from VM page cache */
 #define MADV_VPS_INHERIT 7              /* Inherit parents page size */
+#define MADV_REMOVE     8		/* remove these pages & resources */
 
 /* The range 12-64 is reserved for page size specification. */
 #define MADV_4K_PAGES   12              /* Use 4K pages  */
diff --git a/include/asm-powerpc/mman.h b/include/asm-powerpc/mman.h
index f5e5342..a2e34c2 100644
--- a/include/asm-powerpc/mman.h
+++ b/include/asm-powerpc/mman.h
@@ -44,6 +44,7 @@
 #define MADV_SEQUENTIAL	0x2		/* read-ahead aggressively */
 #define MADV_WILLNEED	0x3		/* pre-fault pages */
 #define MADV_DONTNEED	0x4		/* discard these pages */
+#define MADV_REMOVE	0x5		/* remove these pages & resources */
 
 /* compatibility flags */
 #define MAP_ANON	MAP_ANONYMOUS
diff --git a/include/asm-s390/mman.h b/include/asm-s390/mman.h
index ea86bd1..c8d5409 100644
--- a/include/asm-s390/mman.h
+++ b/include/asm-s390/mman.h
@@ -43,6 +43,7 @@
 #define MADV_SEQUENTIAL        0x2             /* read-ahead aggressively */
 #define MADV_WILLNEED  0x3              /* pre-fault pages */
 #define MADV_DONTNEED  0x4              /* discard these pages */
+#define MADV_REMOVE    0x5		/* remove these pages & resources */
 
 /* compatibility flags */
 #define MAP_ANON	MAP_ANONYMOUS
diff --git a/include/asm-sh/mman.h b/include/asm-sh/mman.h
index 3ebab5f..693bd55 100644
--- a/include/asm-sh/mman.h
+++ b/include/asm-sh/mman.h
@@ -35,6 +35,7 @@
 #define MADV_SEQUENTIAL	0x2		/* read-ahead aggressively */
 #define MADV_WILLNEED	0x3		/* pre-fault pages */
 #define MADV_DONTNEED	0x4		/* discard these pages */
+#define MADV_REMOVE	0x5		/* remove these pages & resources */
 
 /* compatibility flags */
 #define MAP_ANON	MAP_ANONYMOUS
diff --git a/include/asm-sparc/mman.h b/include/asm-sparc/mman.h
index 138eb81..98435ad 100644
--- a/include/asm-sparc/mman.h
+++ b/include/asm-sparc/mman.h
@@ -54,6 +54,7 @@
 #define MADV_WILLNEED	0x3		/* pre-fault pages */
 #define MADV_DONTNEED	0x4		/* discard these pages */
 #define MADV_FREE	0x5		/* (Solaris) contents can be freed */
+#define MADV_REMOVE	0x6		/* remove these pages & resources */
 
 /* compatibility flags */
 #define MAP_ANON	MAP_ANONYMOUS
diff --git a/include/asm-sparc64/mman.h b/include/asm-sparc64/mman.h
index 01cecf5..cb4b615 100644
--- a/include/asm-sparc64/mman.h
+++ b/include/asm-sparc64/mman.h
@@ -54,6 +54,7 @@
 #define MADV_WILLNEED	0x3		/* pre-fault pages */
 #define MADV_DONTNEED	0x4		/* discard these pages */
 #define MADV_FREE	0x5		/* (Solaris) contents can be freed */
+#define MADV_REMOVE	0x6		/* remove these pages & resources */
 
 /* compatibility flags */
 #define MAP_ANON	MAP_ANONYMOUS
diff --git a/include/asm-v850/mman.h b/include/asm-v850/mman.h
index e2b9008..edc7996 100644
--- a/include/asm-v850/mman.h
+++ b/include/asm-v850/mman.h
@@ -32,6 +32,7 @@
 #define MADV_SEQUENTIAL	0x2		/* read-ahead aggressively */
 #define MADV_WILLNEED	0x3		/* pre-fault pages */
 #define MADV_DONTNEED	0x4		/* discard these pages */
+#define MADV_REMOVE	0x5		/* remove these pages & resources */
 
 /* compatibility flags */
 #define MAP_ANON	MAP_ANONYMOUS
diff --git a/include/asm-x86_64/mman.h b/include/asm-x86_64/mman.h
index 78e60a4..d0e97b7 100644
--- a/include/asm-x86_64/mman.h
+++ b/include/asm-x86_64/mman.h
@@ -36,6 +36,7 @@
 #define MADV_SEQUENTIAL	0x2		/* read-ahead aggressively */
 #define MADV_WILLNEED	0x3		/* pre-fault pages */
 #define MADV_DONTNEED	0x4		/* discard these pages */
+#define MADV_REMOVE	0x5		/* remove these pages & resources */
 
 /* compatibility flags */
 #define MAP_ANON	MAP_ANONYMOUS
diff --git a/include/asm-xtensa/mman.h b/include/asm-xtensa/mman.h
index 9a95a45..082a750 100644
--- a/include/asm-xtensa/mman.h
+++ b/include/asm-xtensa/mman.h
@@ -72,6 +72,7 @@
 #define MADV_SEQUENTIAL	0x2		/* read-ahead aggressively */
 #define MADV_WILLNEED	0x3		/* pre-fault pages */
 #define MADV_DONTNEED	0x4		/* discard these pages */
+#define MADV_REMOVE	0x5		/* remove these pages & resources */
 
 /* compatibility flags */
 #define MAP_ANON       MAP_ANONYMOUS
diff --git a/include/linux/fs.h b/include/linux/fs.h
index ed9a41a..115e72b 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1050,6 +1050,7 @@ struct inode_operations {
 	ssize_t (*getxattr) (struct dentry *, const char *, void *, size_t);
 	ssize_t (*listxattr) (struct dentry *, char *, size_t);
 	int (*removexattr) (struct dentry *, const char *);
+	void (*truncate_range)(struct inode *, loff_t, loff_t);
 };
 
 struct seq_file;
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 92acae9..6c9be99 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -690,6 +690,7 @@ static inline void unmap_shared_mapping_range(struct address_space *mapping,
 }
 
 extern int vmtruncate(struct inode * inode, loff_t offset);
+extern int vmtruncate_range(struct inode * inode, loff_t offset, loff_t end);
 extern int install_page(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long addr, struct page *page, pgprot_t prot);
 extern int install_file_pte(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long addr, unsigned long pgoff, pgprot_t prot);
 extern int __handle_mm_fault(struct mm_struct *mm,struct vm_area_struct *vma, unsigned long address, int write_access);
diff --git a/mm/madvise.c b/mm/madvise.c
index 2b7cf04..ae0ae3e 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -140,6 +140,36 @@ static long madvise_dontneed(struct vm_area_struct * vma,
 	return 0;
 }
 
+/*
+ * Application wants to free up the pages and associated backing store.
+ * This is effectively punching a hole into the middle of a file.
+ *
+ * NOTE: Currently, only shmfs/tmpfs is supported for this operation.
+ * Other filesystems return -ENOSYS.
+ */
+static long madvise_remove(struct vm_area_struct *vma,
+				unsigned long start, unsigned long end)
+{
+	struct address_space *mapping;
+        loff_t offset, endoff;
+
+	if (vma->vm_flags & (VM_LOCKED|VM_NONLINEAR|VM_HUGETLB))
+		return -EINVAL;
+
+	if (!vma->vm_file || !vma->vm_file->f_mapping
+		|| !vma->vm_file->f_mapping->host) {
+			return -EINVAL;
+	}
+
+	mapping = vma->vm_file->f_mapping;
+
+	offset = (loff_t)(start - vma->vm_start)
+			+ ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
+	endoff = (loff_t)(end - vma->vm_start - 1)
+			+ ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
+	return  vmtruncate_range(mapping->host, offset, endoff);
+}
+
 static long
 madvise_vma(struct vm_area_struct *vma, struct vm_area_struct **prev,
 		unsigned long start, unsigned long end, int behavior)
@@ -152,6 +182,9 @@ madvise_vma(struct vm_area_struct *vma, struct vm_area_struct **prev,
 	case MADV_RANDOM:
 		error = madvise_behavior(vma, prev, start, end, behavior);
 		break;
+	case MADV_REMOVE:
+		error = madvise_remove(vma, start, end);
+		break;
 
 	case MADV_WILLNEED:
 		error = madvise_willneed(vma, prev, start, end);
@@ -190,6 +223,8 @@ madvise_vma(struct vm_area_struct *vma, struct vm_area_struct **prev,
  *		some pages ahead.
  *  MADV_DONTNEED - the application is finished with the given range,
  *		so the kernel can free resources associated with it.
+ *  MADV_REMOVE - the application wants to free up the given range of
+ *		pages and associated backing store.
  *
  * return values:
  *  zero    - success
diff --git a/mm/memory.c b/mm/memory.c
index d8dde07..e249088 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1770,9 +1770,32 @@ out_big:
 out_busy:
 	return -ETXTBSY;
 }
-
 EXPORT_SYMBOL(vmtruncate);
 
+int vmtruncate_range(struct inode *inode, loff_t offset, loff_t end)
+{
+	struct address_space *mapping = inode->i_mapping;
+
+	/*
+	 * 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.
+	 */
+	if (!inode->i_op || !inode->i_op->truncate_range)
+		return -ENOSYS;
+
+	down(&inode->i_sem);
+	down_write(&inode->i_alloc_sem);
+	unmap_mapping_range(mapping, offset, (end - offset), 1);
+	truncate_inode_pages_range(mapping, offset, end);
+	inode->i_op->truncate_range(inode, offset, end);
+	up_write(&inode->i_alloc_sem);
+	up(&inode->i_sem);
+
+	return 0;
+}
+EXPORT_SYMBOL(vmtruncate_range);
+
 /* 
  * Primitive swap readahead code. We simply read an aligned block of
  * (1 << page_cluster) entries in the swap area. This method is chosen
diff --git a/mm/shmem.c b/mm/shmem.c
index d9fc277..65c148e 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -457,7 +457,7 @@ static void shmem_free_pages(struct list_head *next)
 	} while (next);
 }
 
-static void shmem_truncate(struct inode *inode)
+static void shmem_truncate_range(struct inode *inode, loff_t start, loff_t end)
 {
 	struct shmem_inode_info *info = SHMEM_I(inode);
 	unsigned long idx;
@@ -475,18 +475,27 @@ static void shmem_truncate(struct inode *inode)
 	long nr_swaps_freed = 0;
 	int offset;
 	int freed;
+	int punch_hole = 0;
 
 	inode->i_ctime = inode->i_mtime = CURRENT_TIME;
-	idx = (inode->i_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
+	idx = (start + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
 	if (idx >= info->next_index)
 		return;
 
 	spin_lock(&info->lock);
 	info->flags |= SHMEM_TRUNCATE;
-	limit = info->next_index;
-	info->next_index = idx;
+	if (likely(end == (loff_t) -1)) {
+		limit = info->next_index;
+		info->next_index = idx;
+	} else {
+		limit = (end + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
+		if (limit > info->next_index)
+			limit = info->next_index;
+		punch_hole = 1;
+	}
+
 	topdir = info->i_indirect;
-	if (topdir && idx <= SHMEM_NR_DIRECT) {
+	if (topdir && idx <= SHMEM_NR_DIRECT && !punch_hole) {
 		info->i_indirect = NULL;
 		nr_pages_to_free++;
 		list_add(&topdir->lru, &pages_to_free);
@@ -573,11 +582,12 @@ static void shmem_truncate(struct inode *inode)
 			set_page_private(subdir, page_private(subdir) - freed);
 			if (offset)
 				spin_unlock(&info->lock);
-			BUG_ON(page_private(subdir) > offset);
+			if (!punch_hole)
+				BUG_ON(page_private(subdir) > offset);
 		}
 		if (offset)
 			offset = 0;
-		else if (subdir) {
+		else if (subdir && !page_private(subdir)) {
 			dir[diroff] = NULL;
 			nr_pages_to_free++;
 			list_add(&subdir->lru, &pages_to_free);
@@ -594,7 +604,7 @@ done2:
 		 * Also, though shmem_getpage checks i_size before adding to
 		 * cache, no recheck after: so fix the narrow window there too.
 		 */
-		truncate_inode_pages(inode->i_mapping, inode->i_size);
+		truncate_inode_pages_range(inode->i_mapping, start, end);
 	}
 
 	spin_lock(&info->lock);
@@ -614,6 +624,11 @@ done2:
 	}
 }
 
+static void shmem_truncate(struct inode *inode)
+{
+	shmem_truncate_range(inode, inode->i_size, (loff_t)-1);
+}
+
 static int shmem_notify_change(struct dentry *dentry, struct iattr *attr)
 {
 	struct inode *inode = dentry->d_inode;
@@ -2083,6 +2098,7 @@ static struct file_operations shmem_file_operations = {
 static struct inode_operations shmem_inode_operations = {
 	.truncate	= shmem_truncate,
 	.setattr	= shmem_notify_change,
+	.truncate_range	= shmem_truncate_range,
 };
 
 static struct inode_operations shmem_dir_inode_operations = {