diff options
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/dax.c | 44 | ||||
| -rw-r--r-- | fs/ext2/inode.c | 2 |
2 files changed, 45 insertions, 1 deletions
@@ -462,3 +462,47 @@ int dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf, return result; } EXPORT_SYMBOL_GPL(dax_fault); + +/** + * dax_truncate_page - handle a partial page being truncated in a DAX file + * @inode: The file being truncated + * @from: The file offset that is being truncated to + * @get_block: The filesystem method used to translate file offsets to blocks + * + * Similar to block_truncate_page(), this function can be called by a + * filesystem when it is truncating an DAX file to handle the partial page. + * + * We work in terms of PAGE_CACHE_SIZE here for commonality with + * block_truncate_page(), but we could go down to PAGE_SIZE if the filesystem + * took care of disposing of the unnecessary blocks. Even if the filesystem + * block size is smaller than PAGE_SIZE, we have to zero the rest of the page + * since the file might be mmaped. + */ +int dax_truncate_page(struct inode *inode, loff_t from, get_block_t get_block) +{ + struct buffer_head bh; + pgoff_t index = from >> PAGE_CACHE_SHIFT; + unsigned offset = from & (PAGE_CACHE_SIZE-1); + unsigned length = PAGE_CACHE_ALIGN(from) - from; + int err; + + /* Block boundary? Nothing to do */ + if (!length) + return 0; + + memset(&bh, 0, sizeof(bh)); + bh.b_size = PAGE_CACHE_SIZE; + err = get_block(inode, index, &bh, 0); + if (err < 0) + return err; + if (buffer_written(&bh)) { + void *addr; + err = dax_get_addr(&bh, &addr, inode->i_blkbits); + if (err < 0) + return err; + memset(addr + offset, 0, length); + } + + return 0; +} +EXPORT_SYMBOL_GPL(dax_truncate_page); diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c index 52978b853226..5ac0a3461b3c 100644 --- a/fs/ext2/inode.c +++ b/fs/ext2/inode.c @@ -1210,7 +1210,7 @@ static int ext2_setsize(struct inode *inode, loff_t newsize) inode_dio_wait(inode); if (IS_DAX(inode)) - error = xip_truncate_page(inode->i_mapping, newsize); + error = dax_truncate_page(inode, newsize, ext2_get_block); else if (test_opt(inode->i_sb, NOBH)) error = nobh_truncate_page(inode->i_mapping, newsize, ext2_get_block); |