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SubjectRe: [PATCH] 2.6.14 patch for supporting madvise(MADV_REMOVE)
From
Date
Hi Andrew & Andrea,

Here is the updated patch with name change again :(
Hopefully this would be final. (MADV_REMOVE).

BTW, I am not sure if we need to hold i_sem and i_allocsem
all the way ? I wanted to be safe - but this may be overkill ?


+ /* XXX - Do we need both i_sem and i_allocsem all the way ? */
+ 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);

Thanks,
Badari


diff -Naurp -X dontdiff linux-2.6.14/include/asm-alpha/mman.h linux-2.6.14.madv/include/asm-alpha/mman.h
--- linux-2.6.14/include/asm-alpha/mman.h 2005-10-27 17:02:08.000000000 -0700
+++ linux-2.6.14.madv/include/asm-alpha/mman.h 2005-11-02 03:03:55.000000000 -0800
@@ -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 -Naurp -X dontdiff linux-2.6.14/include/asm-arm/mman.h linux-2.6.14.madv/include/asm-arm/mman.h
--- linux-2.6.14/include/asm-arm/mman.h 2005-10-27 17:02:08.000000000 -0700
+++ linux-2.6.14.madv/include/asm-arm/mman.h 2005-11-02 03:03:55.000000000 -0800
@@ -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 -Naurp -X dontdiff linux-2.6.14/include/asm-arm26/mman.h linux-2.6.14.madv/include/asm-arm26/mman.h
--- linux-2.6.14/include/asm-arm26/mman.h 2005-10-27 17:02:08.000000000 -0700
+++ linux-2.6.14.madv/include/asm-arm26/mman.h 2005-11-02 03:03:55.000000000 -0800
@@ -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 -Naurp -X dontdiff linux-2.6.14/include/asm-cris/mman.h linux-2.6.14.madv/include/asm-cris/mman.h
--- linux-2.6.14/include/asm-cris/mman.h 2005-10-27 17:02:08.000000000 -0700
+++ linux-2.6.14.madv/include/asm-cris/mman.h 2005-11-02 03:03:55.000000000 -0800
@@ -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 -Naurp -X dontdiff linux-2.6.14/include/asm-frv/mman.h linux-2.6.14.madv/include/asm-frv/mman.h
--- linux-2.6.14/include/asm-frv/mman.h 2005-10-27 17:02:08.000000000 -0700
+++ linux-2.6.14.madv/include/asm-frv/mman.h 2005-11-02 03:03:55.000000000 -0800
@@ -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 -Naurp -X dontdiff linux-2.6.14/include/asm-h8300/mman.h linux-2.6.14.madv/include/asm-h8300/mman.h
--- linux-2.6.14/include/asm-h8300/mman.h 2005-10-27 17:02:08.000000000 -0700
+++ linux-2.6.14.madv/include/asm-h8300/mman.h 2005-11-02 03:03:55.000000000 -0800
@@ -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 -Naurp -X dontdiff linux-2.6.14/include/asm-i386/mman.h linux-2.6.14.madv/include/asm-i386/mman.h
--- linux-2.6.14/include/asm-i386/mman.h 2005-10-27 17:02:08.000000000 -0700
+++ linux-2.6.14.madv/include/asm-i386/mman.h 2005-11-02 03:03:55.000000000 -0800
@@ -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 -Naurp -X dontdiff linux-2.6.14/include/asm-ia64/mman.h linux-2.6.14.madv/include/asm-ia64/mman.h
--- linux-2.6.14/include/asm-ia64/mman.h 2005-10-27 17:02:08.000000000 -0700
+++ linux-2.6.14.madv/include/asm-ia64/mman.h 2005-11-02 03:03:55.000000000 -0800
@@ -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 -Naurp -X dontdiff linux-2.6.14/include/asm-m32r/mman.h linux-2.6.14.madv/include/asm-m32r/mman.h
--- linux-2.6.14/include/asm-m32r/mman.h 2005-10-27 17:02:08.000000000 -0700
+++ linux-2.6.14.madv/include/asm-m32r/mman.h 2005-11-02 03:03:55.000000000 -0800
@@ -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 -Naurp -X dontdiff linux-2.6.14/include/asm-m68k/mman.h linux-2.6.14.madv/include/asm-m68k/mman.h
--- linux-2.6.14/include/asm-m68k/mman.h 2005-10-27 17:02:08.000000000 -0700
+++ linux-2.6.14.madv/include/asm-m68k/mman.h 2005-11-02 03:03:55.000000000 -0800
@@ -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 -Naurp -X dontdiff linux-2.6.14/include/asm-mips/mman.h linux-2.6.14.madv/include/asm-mips/mman.h
--- linux-2.6.14/include/asm-mips/mman.h 2005-10-27 17:02:08.000000000 -0700
+++ linux-2.6.14.madv/include/asm-mips/mman.h 2005-11-02 03:03:55.000000000 -0800
@@ -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 -Naurp -X dontdiff linux-2.6.14/include/asm-parisc/mman.h linux-2.6.14.madv/include/asm-parisc/mman.h
--- linux-2.6.14/include/asm-parisc/mman.h 2005-10-27 17:02:08.000000000 -0700
+++ linux-2.6.14.madv/include/asm-parisc/mman.h 2005-11-02 03:12:02.000000000 -0800
@@ -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 -Naurp -X dontdiff linux-2.6.14/include/asm-powerpc/mman.h linux-2.6.14.madv/include/asm-powerpc/mman.h
--- linux-2.6.14/include/asm-powerpc/mman.h 2005-10-27 17:02:08.000000000 -0700
+++ linux-2.6.14.madv/include/asm-powerpc/mman.h 2005-11-02 03:03:55.000000000 -0800
@@ -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 -Naurp -X dontdiff linux-2.6.14/include/asm-s390/mman.h linux-2.6.14.madv/include/asm-s390/mman.h
--- linux-2.6.14/include/asm-s390/mman.h 2005-10-27 17:02:08.000000000 -0700
+++ linux-2.6.14.madv/include/asm-s390/mman.h 2005-11-02 03:12:13.000000000 -0800
@@ -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 -Naurp -X dontdiff linux-2.6.14/include/asm-sh/mman.h linux-2.6.14.madv/include/asm-sh/mman.h
--- linux-2.6.14/include/asm-sh/mman.h 2005-10-27 17:02:08.000000000 -0700
+++ linux-2.6.14.madv/include/asm-sh/mman.h 2005-11-02 03:03:55.000000000 -0800
@@ -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 -Naurp -X dontdiff linux-2.6.14/include/asm-sparc/mman.h linux-2.6.14.madv/include/asm-sparc/mman.h
--- linux-2.6.14/include/asm-sparc/mman.h 2005-10-27 17:02:08.000000000 -0700
+++ linux-2.6.14.madv/include/asm-sparc/mman.h 2005-11-02 03:04:57.000000000 -0800
@@ -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 -Naurp -X dontdiff linux-2.6.14/include/asm-sparc64/mman.h linux-2.6.14.madv/include/asm-sparc64/mman.h
--- linux-2.6.14/include/asm-sparc64/mman.h 2005-10-27 17:02:08.000000000 -0700
+++ linux-2.6.14.madv/include/asm-sparc64/mman.h 2005-11-02 03:04:35.000000000 -0800
@@ -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 -Naurp -X dontdiff linux-2.6.14/include/asm-v850/mman.h linux-2.6.14.madv/include/asm-v850/mman.h
--- linux-2.6.14/include/asm-v850/mman.h 2005-10-27 17:02:08.000000000 -0700
+++ linux-2.6.14.madv/include/asm-v850/mman.h 2005-11-02 03:03:55.000000000 -0800
@@ -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 -Naurp -X dontdiff linux-2.6.14/include/asm-x86_64/mman.h linux-2.6.14.madv/include/asm-x86_64/mman.h
--- linux-2.6.14/include/asm-x86_64/mman.h 2005-10-27 17:02:08.000000000 -0700
+++ linux-2.6.14.madv/include/asm-x86_64/mman.h 2005-11-02 03:03:55.000000000 -0800
@@ -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 -Naurp -X dontdiff linux-2.6.14/include/asm-xtensa/mman.h linux-2.6.14.madv/include/asm-xtensa/mman.h
--- linux-2.6.14/include/asm-xtensa/mman.h 2005-10-27 17:02:08.000000000 -0700
+++ linux-2.6.14.madv/include/asm-xtensa/mman.h 2005-11-02 03:03:55.000000000 -0800
@@ -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 -Naurp -X dontdiff linux-2.6.14/include/linux/fs.h linux-2.6.14.madv/include/linux/fs.h
--- linux-2.6.14/include/linux/fs.h 2005-10-27 17:02:08.000000000 -0700
+++ linux-2.6.14.madv/include/linux/fs.h 2005-11-02 03:03:55.000000000 -0800
@@ -995,6 +995,7 @@ 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 -Naurp -X dontdiff linux-2.6.14/include/linux/mm.h linux-2.6.14.madv/include/linux/mm.h
--- linux-2.6.14/include/linux/mm.h 2005-10-27 17:02:08.000000000 -0700
+++ linux-2.6.14.madv/include/linux/mm.h 2005-11-02 03:03:55.000000000 -0800
@@ -704,6 +704,7 @@ static inline void unmap_shared_mapping_
}

extern int vmtruncate(struct inode * inode, loff_t offset);
+extern int vmtruncate_range(struct inode * inode, loff_t offset, loff_t end);
extern pud_t *FASTCALL(__pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address));
extern pmd_t *FASTCALL(__pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address));
extern pte_t *FASTCALL(pte_alloc_kernel(struct mm_struct *mm, pmd_t *pmd, unsigned long address));
@@ -865,6 +866,7 @@ extern unsigned long do_brk(unsigned lon
/* filemap.c */
extern unsigned long page_unuse(struct page *);
extern void truncate_inode_pages(struct address_space *, loff_t);
+extern void truncate_inode_pages_range(struct address_space *, loff_t, loff_t);

/* generic vm_area_ops exported for stackable file systems */
extern struct page *filemap_nopage(struct vm_area_struct *, unsigned long, int *);
diff -Naurp -X dontdiff linux-2.6.14/mm/madvise.c linux-2.6.14.madv/mm/madvise.c
--- linux-2.6.14/mm/madvise.c 2005-10-27 17:02:08.000000000 -0700
+++ linux-2.6.14.madv/mm/madvise.c 2005-11-02 03:03:55.000000000 -0800
@@ -140,6 +140,39 @@ static long madvise_dontneed(struct vm_a
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;
+ if (mapping == &swapper_space) {
+ return -EINVAL;
+ }
+
+ offset = (loff_t)(start - vma->vm_start)
+ + (vma->vm_pgoff << PAGE_SHIFT);
+ endoff = (loff_t)(end - vma->vm_start - 1)
+ + (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 +185,9 @@ madvise_vma(struct vm_area_struct *vma,
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 +226,8 @@ madvise_vma(struct vm_area_struct *vma,
* 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 -Naurp -X dontdiff linux-2.6.14/mm/memory.c linux-2.6.14.madv/mm/memory.c
--- linux-2.6.14/mm/memory.c 2005-10-27 17:02:08.000000000 -0700
+++ linux-2.6.14.madv/mm/memory.c 2005-11-02 03:03:55.000000000 -0800
@@ -1597,6 +1597,32 @@ out_busy:

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;
+
+ /* XXX - Do we need both i_sem and i_allocsem all the way ? */
+ 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 -Naurp -X dontdiff linux-2.6.14/mm/shmem.c linux-2.6.14.madv/mm/shmem.c
--- linux-2.6.14/mm/shmem.c 2005-10-27 17:02:08.000000000 -0700
+++ linux-2.6.14.madv/mm/shmem.c 2005-11-02 03:03:55.000000000 -0800
@@ -459,7 +459,7 @@ static void shmem_free_pages(struct list
} 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;
@@ -477,18 +477,27 @@ static void shmem_truncate(struct 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);
@@ -575,11 +584,12 @@ static void shmem_truncate(struct inode
subdir->nr_swapped -= freed;
if (offset)
spin_unlock(&info->lock);
- BUG_ON(subdir->nr_swapped > offset);
+ if (!punch_hole)
+ BUG_ON(subdir->nr_swapped > offset);
}
if (offset)
offset = 0;
- else if (subdir) {
+ else if (subdir && !subdir->nr_swapped) {
dir[diroff] = NULL;
nr_pages_to_free++;
list_add(&subdir->lru, &pages_to_free);
@@ -596,7 +606,7 @@ 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);
@@ -616,6 +626,11 @@ 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
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 = {
diff -Naurp -X dontdiff linux-2.6.14/mm/truncate.c linux-2.6.14.madv/mm/truncate.c
--- linux-2.6.14/mm/truncate.c 2005-10-27 17:02:08.000000000 -0700
+++ linux-2.6.14.madv/mm/truncate.c 2005-11-02 03:03:55.000000000 -0800
@@ -91,12 +91,15 @@ invalidate_complete_page(struct address_
}

/**
- * truncate_inode_pages - truncate *all* the pages from an offset
+ * truncate_inode_pages - truncate range of pages specified by start and
+ * end byte offsets
* @mapping: mapping to truncate
* @lstart: offset from which to truncate
+ * @lend: offset to which to truncate
*
- * Truncate the page cache at a set offset, removing the pages that are beyond
- * that offset (and zeroing out partial pages).
+ * Truncate the page cache, removing the pages that are between
+ * specified offsets (and zeroing out partial page
+ * (if lstart 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
@@ -110,12 +113,12 @@ invalidate_complete_page(struct address_
* 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.
- *
- * Called under (and serialised by) inode->i_sem.
*/
-void truncate_inode_pages(struct address_space *mapping, loff_t lstart)
+void truncate_inode_pages_range(struct address_space *mapping,
+ loff_t lstart, loff_t lend)
{
const pgoff_t start = (lstart + PAGE_CACHE_SIZE-1) >> PAGE_CACHE_SHIFT;
+ pgoff_t end;
const unsigned partial = lstart & (PAGE_CACHE_SIZE - 1);
struct pagevec pvec;
pgoff_t next;
@@ -124,13 +127,22 @@ void truncate_inode_pages(struct address
if (mapping->nrpages == 0)
return;

+ BUG_ON((lend & (PAGE_CACHE_SIZE - 1)) != (PAGE_CACHE_SIZE - 1));
+ end = (lend >> PAGE_CACHE_SHIFT);
+
pagevec_init(&pvec, 0);
next = start;
- while (pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) {
+ while (next <= end &&
+ pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) {
for (i = 0; i < pagevec_count(&pvec); i++) {
struct page *page = pvec.pages[i];
pgoff_t page_index = page->index;

+ if (page_index > end) {
+ next = page_index;
+ break;
+ }
+
if (page_index > next)
next = page_index;
next++;
@@ -166,9 +178,15 @@ void truncate_inode_pages(struct address
next = start;
continue;
}
+ if (pvec.pages[0]->index > end) {
+ pagevec_release(&pvec);
+ break;
+ }
for (i = 0; i < pagevec_count(&pvec); i++) {
struct page *page = pvec.pages[i];

+ if (page->index > end)
+ break;
lock_page(page);
wait_on_page_writeback(page);
if (page->index > next)
@@ -180,7 +198,19 @@ void truncate_inode_pages(struct address
pagevec_release(&pvec);
}
}
+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_sem.
+ */
+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);

/**
\
 
 \ /
  Last update: 2005-11-02 17:15    [from the cache]
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