/*
* xfs_iozero clears the specified range supplied via the page cache (except in
* the DAX case). Writes through the page cache will allocate blocks over holes,
* though the callers usually map the holes first and avoid them. If a block is
* not completely zeroed, then it will be read from disk before being partially
* zeroed.
*
* In the DAX case, we can just directly write to the underlying pages. This
* will not allocate blocks, but will avoid holes and unwritten extents and so
* not do unnecessary work.
*/
int
xfs_iozero(
struct xfs_inode *ip, /* inode */
loff_t pos, /* offset in file */
size_t count) /* size of data to zero */
{
struct page *page;
struct address_space *mapping;
int status = 0;
mapping = VFS_I(ip)->i_mapping;
do {
unsigned offset, bytes;
void *fsdata;
offset = (pos & (PAGE_CACHE_SIZE -1)); /* Within page */
bytes = PAGE_CACHE_SIZE - offset;
if (bytes > count)
bytes = count;
if (IS_DAX(VFS_I(ip))) {
status = dax_zero_page_range(VFS_I(ip), pos, bytes,
xfs_get_blocks_direct);
if (status)
break;
} else {
status = pagecache_write_begin(NULL, mapping, pos, bytes,
AOP_FLAG_UNINTERRUPTIBLE,
&page, &fsdata);
if (status)
break;
zero_user(page, offset, bytes);
status = pagecache_write_end(NULL, mapping, pos, bytes,
bytes, page, fsdata);
WARN_ON(status <= 0); /* can't return less than zero! */
status = 0;
}
pos += bytes;
count -= bytes;
} while (count);
return status;
}
/*
* This is a little more tricky than the file -> pipe splicing. There are
* basically three cases:
*
* - Destination page already exists in the address space and there
* are users of it. For that case we have no other option that
* copying the data. Tough luck.
* - Destination page already exists in the address space, but there
* are no users of it. Make sure it's uptodate, then drop it. Fall
* through to last case.
* - Destination page does not exist, we can add the pipe page to
* the page cache and avoid the copy.
*
* If asked to move pages to the output file (SPLICE_F_MOVE is set in
* sd->flags), we attempt to migrate pages from the pipe to the output
* file address space page cache. This is possible if no one else has
* the pipe page referenced outside of the pipe and page cache. If
* SPLICE_F_MOVE isn't set, or we cannot move the page, we simply create
* a new page in the output file page cache and fill/dirty that.
*/
static int pipe_to_file(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
struct splice_desc *sd)
{
struct file *file = sd->file;
struct address_space *mapping = file->f_mapping;
unsigned int offset, this_len;
struct page *page;
void *fsdata;
int ret;
/*
* make sure the data in this buffer is uptodate
*/
ret = buf->ops->pin(pipe, buf);
if (unlikely(ret))
return ret;
offset = sd->pos & ~PAGE_CACHE_MASK;
this_len = sd->len;
if (this_len + offset > PAGE_CACHE_SIZE)
this_len = PAGE_CACHE_SIZE - offset;
ret = pagecache_write_begin(file, mapping, sd->pos, this_len,
AOP_FLAG_UNINTERRUPTIBLE, &page, &fsdata);
if (unlikely(ret))
goto out;
if (buf->page != page) {
/*
* Careful, ->map() uses KM_USER0!
*/
char *src = buf->ops->map(pipe, buf, 1);
char *dst = kmap_atomic(page, KM_USER1);
memcpy(dst + offset, src + buf->offset, this_len);
flush_dcache_page(page);
kunmap_atomic(dst, KM_USER1);
buf->ops->unmap(pipe, buf, src);
}
ret = pagecache_write_end(file, mapping, sd->pos, this_len, this_len,
page, fsdata);
out:
return ret;
}
/*
* xfs_iozero
*
* xfs_iozero clears the specified range of buffer supplied,
* and marks all the affected blocks as valid and modified. If
* an affected block is not allocated, it will be allocated. If
* an affected block is not completely overwritten, and is not
* valid before the operation, it will be read from disk before
* being partially zeroed.
*/
STATIC int
xfs_iozero(
struct xfs_inode *ip,
loff_t pos,
size_t count)
{
struct page *page;
struct address_space *mapping;
int status;
mapping = VFS_I(ip)->i_mapping;
do {
unsigned offset, bytes;
void *fsdata;
offset = (pos & (PAGE_CACHE_SIZE -1));
bytes = PAGE_CACHE_SIZE - offset;
if (bytes > count)
bytes = count;
status = pagecache_write_begin(NULL, mapping, pos, bytes,
AOP_FLAG_UNINTERRUPTIBLE,
&page, &fsdata);
if (status)
break;
zero_user(page, offset, bytes);
status = pagecache_write_end(NULL, mapping, pos, bytes, bytes,
page, fsdata);
WARN_ON(status <= 0);
pos += bytes;
count -= bytes;
status = 0;
} while (count);
return (-status);
}
/*
* xfs_iozero
*
* xfs_iozero clears the specified range of buffer supplied,
* and marks all the affected blocks as valid and modified. If
* an affected block is not allocated, it will be allocated. If
* an affected block is not completely overwritten, and is not
* valid before the operation, it will be read from disk before
* being partially zeroed.
*/
STATIC int
xfs_iozero(
struct xfs_inode *ip, /* inode */
loff_t pos, /* offset in file */
size_t count) /* size of data to zero */
{
struct page *page;
struct address_space *mapping;
int status;
mapping = ip->i_vnode->i_mapping;
do {
unsigned offset, bytes;
void *fsdata;
offset = (pos & (PAGE_CACHE_SIZE -1)); /* Within page */
bytes = PAGE_CACHE_SIZE - offset;
if (bytes > count)
bytes = count;
status = pagecache_write_begin(NULL, mapping, pos, bytes,
AOP_FLAG_UNINTERRUPTIBLE,
&page, &fsdata);
if (status)
break;
zero_user(page, offset, bytes);
status = pagecache_write_end(NULL, mapping, pos, bytes, bytes,
page, fsdata);
WARN_ON(status <= 0); /* can't return less than zero! */
pos += bytes;
count -= bytes;
status = 0;
} while (count);
return (-status);
}
void hfsplus_file_truncate(struct inode *inode)
{
struct super_block *sb = inode->i_sb;
struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
struct hfs_find_data fd;
u32 alloc_cnt, blk_cnt, start;
int res;
hfs_dbg(INODE, "truncate: %lu, %llu -> %llu\n",
inode->i_ino, (long long)hip->phys_size, inode->i_size);
if (inode->i_size > hip->phys_size) {
struct address_space *mapping = inode->i_mapping;
struct page *page;
void *fsdata;
loff_t size = inode->i_size;
res = pagecache_write_begin(NULL, mapping, size, 0,
AOP_FLAG_UNINTERRUPTIBLE,
&page, &fsdata);
if (res)
return;
res = pagecache_write_end(NULL, mapping, size,
0, 0, page, fsdata);
if (res < 0)
return;
mark_inode_dirty(inode);
return;
} else if (inode->i_size == hip->phys_size)
return;
blk_cnt = (inode->i_size + HFSPLUS_SB(sb)->alloc_blksz - 1) >>
HFSPLUS_SB(sb)->alloc_blksz_shift;
mutex_lock(&hip->extents_lock);
alloc_cnt = hip->alloc_blocks;
if (blk_cnt == alloc_cnt)
goto out_unlock;
res = hfs_find_init(HFSPLUS_SB(sb)->ext_tree, &fd);
if (res) {
mutex_unlock(&hip->extents_lock);
/* XXX: We lack error handling of hfsplus_file_truncate() */
return;
}
while (1) {
if (alloc_cnt == hip->first_blocks) {
hfsplus_free_extents(sb, hip->first_extents,
alloc_cnt, alloc_cnt - blk_cnt);
hfsplus_dump_extent(hip->first_extents);
hip->first_blocks = blk_cnt;
break;
}
res = __hfsplus_ext_cache_extent(&fd, inode, alloc_cnt);
if (res)
break;
start = hip->cached_start;
hfsplus_free_extents(sb, hip->cached_extents,
alloc_cnt - start, alloc_cnt - blk_cnt);
hfsplus_dump_extent(hip->cached_extents);
if (blk_cnt > start) {
hip->extent_state |= HFSPLUS_EXT_DIRTY;
break;
}
alloc_cnt = start;
hip->cached_start = hip->cached_blocks = 0;
hip->extent_state &= ~(HFSPLUS_EXT_DIRTY | HFSPLUS_EXT_NEW);
hfs_brec_remove(&fd);
}
hfs_find_exit(&fd);
hip->alloc_blocks = blk_cnt;
out_unlock:
mutex_unlock(&hip->extents_lock);
hip->phys_size = inode->i_size;
hip->fs_blocks = (inode->i_size + sb->s_blocksize - 1) >>
sb->s_blocksize_bits;
inode_set_bytes(inode, hip->fs_blocks << sb->s_blocksize_bits);
hfsplus_mark_inode_dirty(inode, HFSPLUS_I_ALLOC_DIRTY);
}
void hfs_file_truncate(struct inode *inode)
{
struct super_block *sb = inode->i_sb;
struct hfs_find_data fd;
u16 blk_cnt, alloc_cnt, start;
u32 size;
int res;
dprint(DBG_INODE, "truncate: %lu, %Lu -> %Lu\n", inode->i_ino,
(long long)HFS_I(inode)->phys_size, inode->i_size);
if (inode->i_size > HFS_I(inode)->phys_size) {
struct address_space *mapping = inode->i_mapping;
void *fsdata;
struct page *page;
int res;
/* XXX: Can use generic_cont_expand? */
size = inode->i_size - 1;
res = pagecache_write_begin(NULL, mapping, size+1, 0,
AOP_FLAG_UNINTERRUPTIBLE, &page, &fsdata);
if (!res) {
res = pagecache_write_end(NULL, mapping, size+1, 0, 0,
page, fsdata);
}
if (res)
inode->i_size = HFS_I(inode)->phys_size;
return;
} else if (inode->i_size == HFS_I(inode)->phys_size)
return;
size = inode->i_size + HFS_SB(sb)->alloc_blksz - 1;
blk_cnt = size / HFS_SB(sb)->alloc_blksz;
alloc_cnt = HFS_I(inode)->alloc_blocks;
if (blk_cnt == alloc_cnt)
goto out;
mutex_lock(&HFS_I(inode)->extents_lock);
hfs_find_init(HFS_SB(sb)->ext_tree, &fd);
while (1) {
if (alloc_cnt == HFS_I(inode)->first_blocks) {
hfs_free_extents(sb, HFS_I(inode)->first_extents,
alloc_cnt, alloc_cnt - blk_cnt);
hfs_dump_extent(HFS_I(inode)->first_extents);
HFS_I(inode)->first_blocks = blk_cnt;
break;
}
res = __hfs_ext_cache_extent(&fd, inode, alloc_cnt);
if (res)
break;
start = HFS_I(inode)->cached_start;
hfs_free_extents(sb, HFS_I(inode)->cached_extents,
alloc_cnt - start, alloc_cnt - blk_cnt);
hfs_dump_extent(HFS_I(inode)->cached_extents);
if (blk_cnt > start) {
HFS_I(inode)->flags |= HFS_FLG_EXT_DIRTY;
break;
}
alloc_cnt = start;
HFS_I(inode)->cached_start = HFS_I(inode)->cached_blocks = 0;
HFS_I(inode)->flags &= ~(HFS_FLG_EXT_DIRTY|HFS_FLG_EXT_NEW);
hfs_brec_remove(&fd);
}
hfs_find_exit(&fd);
mutex_unlock(&HFS_I(inode)->extents_lock);
HFS_I(inode)->alloc_blocks = blk_cnt;
out:
HFS_I(inode)->phys_size = inode->i_size;
HFS_I(inode)->fs_blocks = (inode->i_size + sb->s_blocksize - 1) >> sb->s_blocksize_bits;
inode_set_bytes(inode, HFS_I(inode)->fs_blocks << sb->s_blocksize_bits);
mark_inode_dirty(inode);
}
