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f2fs: introduce f2fs_seek_block to support SEEK_{DATA, HOLE} in llseek

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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@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
This commit is contained in:
Chao Yu 2014-04-23 14:10:24 +08:00 committed by Jaegeuk Kim
parent 2163d19815
commit 267378d4de
2 changed files with 97 additions and 1 deletions
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6
fs/f2fs/f2fs.h
View file

@ -1079,6 +1079,12 @@ 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
*/

92
fs/f2fs/file.c
View file

@ -194,6 +194,96 @@ int f2fs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
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);
@ -675,7 +765,7 @@ 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,