diff options
Diffstat (limited to 'mm/shmem.c')
| -rw-r--r-- | mm/shmem.c | 40 |
1 files changed, 28 insertions, 12 deletions
diff --git a/mm/shmem.c b/mm/shmem.c index d9fc277940d..343b3c0937e 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; @@ -1255,7 +1270,7 @@ out_nomem: return retval; } -static int shmem_mmap(struct file *file, struct vm_area_struct *vma) +int shmem_mmap(struct file *file, struct vm_area_struct *vma) { file_accessed(file); vma->vm_ops = &shmem_vm_ops; @@ -1355,7 +1370,7 @@ shmem_file_write(struct file *file, const char __user *buf, size_t count, loff_t if (!access_ok(VERIFY_READ, buf, count)) return -EFAULT; - down(&inode->i_sem); + mutex_lock(&inode->i_mutex); pos = *ppos; written = 0; @@ -1440,7 +1455,7 @@ shmem_file_write(struct file *file, const char __user *buf, size_t count, loff_t if (written) err = written; out: - up(&inode->i_sem); + mutex_unlock(&inode->i_mutex); return err; } @@ -1476,7 +1491,7 @@ static void do_shmem_file_read(struct file *filp, loff_t *ppos, read_descriptor_ /* * We must evaluate after, since reads (unlike writes) - * are called without i_sem protection against truncate + * are called without i_mutex protection against truncate */ nr = PAGE_CACHE_SIZE; i_size = i_size_read(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 = { |