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authorRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>2009-05-11 20:58:47 +0200
committerRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>2009-06-10 16:41:11 +0200
commit003ff182fddde09ddfb8d079bbdb02f9d2122082 (patch)
treed949fa673353767d8854355987e49d82821935f6 /fs/nilfs2/cpfile.h
parentNILFS2: Pagecache usage optimization on NILFS2 (diff)
downloadlinux-003ff182fddde09ddfb8d079bbdb02f9d2122082.tar.xz
linux-003ff182fddde09ddfb8d079bbdb02f9d2122082.zip
nilfs2: allow future expansion of metadata read out via get info ioctl
Nilfs has some ioctl commands to read out metadata from meta data files: - NILFS_IOCTL_GET_CPINFO for checkpoint file, - NILFS_IOCTL_GET_SUINFO for segment usage file, and - NILFS_IOCTL_GET_VINFO for Disk Address Transalation (DAT) file, respectively. Every routine on these metadata files is implemented so that it allows future expansion of on-disk format. But, the above ioctl commands do not support expansion even though nilfs_argv structure can handle arbitrary size for data exchanged via ioctl. This allows future expansion of the following structures which give basic format of the "get information" ioctls: - struct nilfs_cpinfo - struct nilfs_suinfo - struct nilfs_vinfo So, this introduces forward compatility of such ioctl commands. In this patch, a sanity check in nilfs_ioctl_get_info() function is changed to accept larger data structure [1], and metadata read routines are rewritten so that they become compatible for larger structures; the routines will just ignore the remaining fields which the current version of nilfs doesn't know. [1] The ioctl function already has another upper limit (PAGE_SIZE against a structure, which appears in nilfs_ioctl_wrap_copy function), and this will not cause security problem. Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Diffstat (limited to 'fs/nilfs2/cpfile.h')
-rw-r--r--fs/nilfs2/cpfile.h4
1 files changed, 2 insertions, 2 deletions
diff --git a/fs/nilfs2/cpfile.h b/fs/nilfs2/cpfile.h
index 1a8a1008c342..788a45950197 100644
--- a/fs/nilfs2/cpfile.h
+++ b/fs/nilfs2/cpfile.h
@@ -39,7 +39,7 @@ int nilfs_cpfile_delete_checkpoint(struct inode *, __u64);
int nilfs_cpfile_change_cpmode(struct inode *, __u64, int);
int nilfs_cpfile_is_snapshot(struct inode *, __u64);
int nilfs_cpfile_get_stat(struct inode *, struct nilfs_cpstat *);
-ssize_t nilfs_cpfile_get_cpinfo(struct inode *, __u64 *, int,
- struct nilfs_cpinfo *, size_t);
+ssize_t nilfs_cpfile_get_cpinfo(struct inode *, __u64 *, int, void *, unsigned,
+ size_t);
#endif /* _NILFS_CPFILE_H */