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f2fs: fix incorrect mapping for bmap

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The test step is like below:
1. touch file
2. truncate -s $((1024*1024)) file
3. fallocate -o 0 -l $((1024*1024)) file
4. fibmap.f2fs file

Our result of fibmap.f2fs showed below is not correct:

file_pos   start_blk     end_blk        blks
       0    -937166132    -937166132           1
    4096    -937166132    -937166132           1
    8192    -937166132    -937166132           1
   12288    -937166132    -937166132           1
   16384    -937166132    -937166132           1
   20480    -937166132    -937166132           1
...
 1040384    -937166132    -937166132           1
 1044480    -937166132    -937166132           1

This is because f2fs_map_blocks will return with no error when meeting
a hole or preallocated block, the caller __get_data_block will map the
uninitialized variable value to bh->b_blocknr.

Unfortunately generic_block_bmap will neither check the return value of
get_data() nor check mapping info of buffer_head, result in returning
the random block address.

After fixing the issue, our result shows correctly:

file_pos   start_blk     end_blk        blks
       0           0           0         256

Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
This commit is contained in:
Chao Yu 2015-08-19 19:11:19 +08:00 committed by Jaegeuk Kim
parent c031f6a904
commit e2b4e2bc88
2 changed files with 43 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

50
fs/f2fs/data.c
View File

@ -561,7 +561,7 @@ static void __allocate_data_blocks(struct inode *inode, loff_t offset,
* c. give the block addresses to blockdev
*/
static int f2fs_map_blocks(struct inode *inode, struct f2fs_map_blocks *map,
int create, bool fiemap)
int create, int flag)
{
unsigned int maxblocks = map->m_len;
struct dnode_of_data dn;
@ -595,8 +595,19 @@ static int f2fs_map_blocks(struct inode *inode, struct f2fs_map_blocks *map,
err = 0;
goto unlock_out;
}
if (dn.data_blkaddr == NEW_ADDR && !fiemap)
goto put_out;
if (dn.data_blkaddr == NEW_ADDR) {
if (flag == F2FS_GET_BLOCK_BMAP) {
err = -ENOENT;
goto put_out;
} else if (flag == F2FS_GET_BLOCK_READ ||
flag == F2FS_GET_BLOCK_DIO) {
goto put_out;
}
/*
* if it is in fiemap call path (flag = F2FS_GET_BLOCK_FIEMAP),
* mark it as mapped and unwritten block.
*/
}
if (dn.data_blkaddr != NULL_ADDR) {
map->m_flags = F2FS_MAP_MAPPED;
@ -611,6 +622,8 @@ static int f2fs_map_blocks(struct inode *inode, struct f2fs_map_blocks *map,
map->m_flags = F2FS_MAP_NEW | F2FS_MAP_MAPPED;
map->m_pblk = dn.data_blkaddr;
} else {
if (flag == F2FS_GET_BLOCK_BMAP)
err = -ENOENT;
goto put_out;
}
@ -633,7 +646,9 @@ static int f2fs_map_blocks(struct inode *inode, struct f2fs_map_blocks *map,
err = 0;
goto unlock_out;
}
if (dn.data_blkaddr == NEW_ADDR && !fiemap)
if (dn.data_blkaddr == NEW_ADDR &&
flag != F2FS_GET_BLOCK_FIEMAP)
goto put_out;
end_offset = ADDRS_PER_PAGE(dn.node_page, F2FS_I(inode));
@ -675,7 +690,7 @@ static int f2fs_map_blocks(struct inode *inode, struct f2fs_map_blocks *map,
}
static int __get_data_block(struct inode *inode, sector_t iblock,
struct buffer_head *bh, int create, bool fiemap)
struct buffer_head *bh, int create, int flag)
{
struct f2fs_map_blocks map;
int ret;
@ -683,7 +698,7 @@ static int __get_data_block(struct inode *inode, sector_t iblock,
map.m_lblk = iblock;
map.m_len = bh->b_size >> inode->i_blkbits;
ret = f2fs_map_blocks(inode, &map, create, fiemap);
ret = f2fs_map_blocks(inode, &map, create, flag);
if (!ret) {
map_bh(bh, inode->i_sb, map.m_pblk);
bh->b_state = (bh->b_state & ~F2FS_MAP_FLAGS) | map.m_flags;
@ -693,15 +708,23 @@ static int __get_data_block(struct inode *inode, sector_t iblock,
}
static int get_data_block(struct inode *inode, sector_t iblock,
struct buffer_head *bh_result, int create)
struct buffer_head *bh_result, int create, int flag)
{
return __get_data_block(inode, iblock, bh_result, create, false);
return __get_data_block(inode, iblock, bh_result, create, flag);
}
static int get_data_block_fiemap(struct inode *inode, sector_t iblock,
static int get_data_block_dio(struct inode *inode, sector_t iblock,
struct buffer_head *bh_result, int create)
{
return __get_data_block(inode, iblock, bh_result, create, true);
return __get_data_block(inode, iblock, bh_result, create,
F2FS_GET_BLOCK_DIO);
}
static int get_data_block_bmap(struct inode *inode, sector_t iblock,
struct buffer_head *bh_result, int create)
{
return __get_data_block(inode, iblock, bh_result, create,
F2FS_GET_BLOCK_BMAP);
}
static inline sector_t logical_to_blk(struct inode *inode, loff_t offset)
@ -745,7 +768,8 @@ int f2fs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
memset(&map_bh, 0, sizeof(struct buffer_head));
map_bh.b_size = len;
ret = get_data_block_fiemap(inode, start_blk, &map_bh, 0);
ret = get_data_block(inode, start_blk, &map_bh, 0,
F2FS_GET_BLOCK_FIEMAP);
if (ret)
goto out;
@ -1530,7 +1554,7 @@ static ssize_t f2fs_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
if (iov_iter_rw(iter) == WRITE)
__allocate_data_blocks(inode, offset, count);
err = blockdev_direct_IO(iocb, inode, iter, offset, get_data_block);
err = blockdev_direct_IO(iocb, inode, iter, offset, get_data_block_dio);
if (err < 0 && iov_iter_rw(iter) == WRITE)
f2fs_write_failed(mapping, offset + count);
@ -1618,7 +1642,7 @@ static sector_t f2fs_bmap(struct address_space *mapping, sector_t block)
if (err)
return err;
}
return generic_block_bmap(mapping, block, get_data_block);
return generic_block_bmap(mapping, block, get_data_block_bmap);
}
const struct address_space_operations f2fs_dblock_aops = {

6
fs/f2fs/f2fs.h
View File

@ -375,6 +375,12 @@ struct f2fs_map_blocks {
unsigned int m_flags;
};
/* for flag in get_data_block */
#define F2FS_GET_BLOCK_READ 0
#define F2FS_GET_BLOCK_DIO 1
#define F2FS_GET_BLOCK_FIEMAP 2
#define F2FS_GET_BLOCK_BMAP 3
/*
* i_advise uses FADVISE_XXX_BIT. We can add additional hints later.
*/