In This patch we introduce f2fs_seek_block to support SEEK_{DATA,HOLE} of lseek(2). change log from v1: o fix bug when lseek from middle of page and fix wrong calculation of PGOFS_OF_NEXT_DNODE macro. Signed-off-by: Chao Yu <chao2.yu@xxxxxxxxxxx> --- fs/f2fs/f2fs.h | 6 ++++ fs/f2fs/file.c | 92 +++++++++++++++++++++++++++++++++++++++++++++++++++++++- 2 files changed, 97 insertions(+), 1 deletion(-) diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h index 97da71d..2397301 100644 --- a/fs/f2fs/f2fs.h +++ b/fs/f2fs/f2fs.h @@ -1074,6 +1074,12 @@ static inline void f2fs_stop_checkpoint(struct f2fs_sb_info *sbi) ((is_inode_flag_set(F2FS_I(i), FI_ACL_MODE)) ? \ (F2FS_I(i)->i_acl_mode) : ((i)->i_mode)) +/* get offset of first page in next direct node */ +#define PGOFS_OF_NEXT_DNODE(pgofs, fi) \ + ((pgofs < ADDRS_PER_INODE(fi)) ? ADDRS_PER_INODE(fi) : \ + (pgofs - ADDRS_PER_INODE(fi) + ADDRS_PER_BLOCK) / \ + ADDRS_PER_BLOCK * ADDRS_PER_BLOCK + ADDRS_PER_INODE(fi)) + /* * file.c */ diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c index 60e7d54..655d7a8 100644 --- a/fs/f2fs/file.c +++ b/fs/f2fs/file.c @@ -194,6 +194,96 @@ out: return ret; } +static loff_t f2fs_seek_block(struct file *file, loff_t offset, int whence) +{ + struct inode *inode = file->f_mapping->host; + loff_t maxbytes = inode->i_sb->s_maxbytes; + struct dnode_of_data dn; + pgoff_t pgofs, end_offset; + loff_t data_ofs = offset, isize; + int err = 0; + + mutex_lock(&inode->i_mutex); + + isize = i_size_read(inode); + if (offset >= isize) + goto fail; + + /* handle inline data case */ + if (f2fs_has_inline_data(inode)) { + if (whence == SEEK_HOLE) + data_ofs = isize; + goto found; + } + + pgofs = (pgoff_t)(offset >> PAGE_CACHE_SHIFT); + + for (; data_ofs < isize; data_ofs = pgofs << PAGE_CACHE_SHIFT) { + set_new_dnode(&dn, inode, NULL, NULL, 0); + err = get_dnode_of_data(&dn, pgofs, LOOKUP_NODE_RA); + if (err && err != -ENOENT) { + goto fail; + } else if (err == -ENOENT) { + /* direct node is not exist */ + if (whence == SEEK_DATA) { + pgofs = PGOFS_OF_NEXT_DNODE(pgofs, + F2FS_I(inode)); + continue; + } else { + goto found; + } + } + + end_offset = IS_INODE(dn.node_page) ? + ADDRS_PER_INODE(F2FS_I(inode)) : ADDRS_PER_BLOCK; + + /* find data/hole in dnode block */ + for (; dn.ofs_in_node < end_offset; + dn.ofs_in_node++, pgofs++, + data_ofs = pgofs << PAGE_CACHE_SHIFT) { + block_t blkaddr; + blkaddr = datablock_addr(dn.node_page, dn.ofs_in_node); + + if ((whence == SEEK_DATA && blkaddr != NULL_ADDR) || + (whence == SEEK_HOLE && blkaddr == NULL_ADDR)) { + f2fs_put_dnode(&dn); + goto found; + } + } + f2fs_put_dnode(&dn); + } + + if (whence == SEEK_DATA) + goto fail; + else + data_ofs = isize; +found: + mutex_unlock(&inode->i_mutex); + return vfs_setpos(file, data_ofs, maxbytes); +fail: + mutex_unlock(&inode->i_mutex); + return -ENXIO; +} + +static loff_t f2fs_llseek(struct file *file, loff_t offset, int whence) +{ + struct inode *inode = file->f_mapping->host; + loff_t maxbytes = inode->i_sb->s_maxbytes; + + switch (whence) { + case SEEK_SET: + case SEEK_CUR: + case SEEK_END: + return generic_file_llseek_size(file, offset, whence, + maxbytes, i_size_read(inode)); + case SEEK_DATA: + case SEEK_HOLE: + return f2fs_seek_block(file, offset, whence); + } + + return -EINVAL; +} + static int f2fs_file_mmap(struct file *file, struct vm_area_struct *vma) { file_accessed(file); @@ -678,7 +768,7 @@ long f2fs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg) #endif const struct file_operations f2fs_file_operations = { - .llseek = generic_file_llseek, + .llseek = f2fs_llseek, .read = do_sync_read, .write = do_sync_write, .aio_read = generic_file_aio_read, -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html