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author | Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp> | 2009-05-11 20:58:47 +0200 |
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committer | Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp> | 2009-06-10 16:41:11 +0200 |
commit | 003ff182fddde09ddfb8d079bbdb02f9d2122082 (patch) | |
tree | d949fa673353767d8854355987e49d82821935f6 /fs/nilfs2/cpfile.c | |
parent | NILFS2: Pagecache usage optimization on NILFS2 (diff) | |
download | linux-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.c')
-rw-r--r-- | fs/nilfs2/cpfile.c | 33 |
1 files changed, 21 insertions, 12 deletions
diff --git a/fs/nilfs2/cpfile.c b/fs/nilfs2/cpfile.c index 300f1cdfa862..b5a8cd6b474f 100644 --- a/fs/nilfs2/cpfile.c +++ b/fs/nilfs2/cpfile.c @@ -384,9 +384,10 @@ static void nilfs_cpfile_checkpoint_to_cpinfo(struct inode *cpfile, } static ssize_t nilfs_cpfile_do_get_cpinfo(struct inode *cpfile, __u64 *cnop, - struct nilfs_cpinfo *ci, size_t nci) + void *buf, unsigned cisz, size_t nci) { struct nilfs_checkpoint *cp; + struct nilfs_cpinfo *ci = buf; struct buffer_head *bh; size_t cpsz = NILFS_MDT(cpfile)->mi_entry_size; __u64 cur_cno = nilfs_mdt_cno(cpfile), cno = *cnop; @@ -410,17 +411,22 @@ static ssize_t nilfs_cpfile_do_get_cpinfo(struct inode *cpfile, __u64 *cnop, kaddr = kmap_atomic(bh->b_page, KM_USER0); cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, bh, kaddr); for (i = 0; i < ncps && n < nci; i++, cp = (void *)cp + cpsz) { - if (!nilfs_checkpoint_invalid(cp)) - nilfs_cpfile_checkpoint_to_cpinfo( - cpfile, cp, &ci[n++]); + if (!nilfs_checkpoint_invalid(cp)) { + nilfs_cpfile_checkpoint_to_cpinfo(cpfile, cp, + ci); + ci = (void *)ci + cisz; + n++; + } } kunmap_atomic(kaddr, KM_USER0); brelse(bh); } ret = n; - if (n > 0) - *cnop = ci[n - 1].ci_cno + 1; + if (n > 0) { + ci = (void *)ci - cisz; + *cnop = ci->ci_cno + 1; + } out: up_read(&NILFS_MDT(cpfile)->mi_sem); @@ -428,11 +434,12 @@ static ssize_t nilfs_cpfile_do_get_cpinfo(struct inode *cpfile, __u64 *cnop, } static ssize_t nilfs_cpfile_do_get_ssinfo(struct inode *cpfile, __u64 *cnop, - struct nilfs_cpinfo *ci, size_t nci) + void *buf, unsigned cisz, size_t nci) { struct buffer_head *bh; struct nilfs_cpfile_header *header; struct nilfs_checkpoint *cp; + struct nilfs_cpinfo *ci = buf; __u64 curr = *cnop, next; unsigned long curr_blkoff, next_blkoff; void *kaddr; @@ -472,7 +479,9 @@ static ssize_t nilfs_cpfile_do_get_ssinfo(struct inode *cpfile, __u64 *cnop, if (unlikely(nilfs_checkpoint_invalid(cp) || !nilfs_checkpoint_snapshot(cp))) break; - nilfs_cpfile_checkpoint_to_cpinfo(cpfile, cp, &ci[n++]); + nilfs_cpfile_checkpoint_to_cpinfo(cpfile, cp, ci); + ci = (void *)ci + cisz; + n++; next = le64_to_cpu(cp->cp_snapshot_list.ssl_next); if (next == 0) break; /* reach end of the snapshot list */ @@ -511,13 +520,13 @@ static ssize_t nilfs_cpfile_do_get_ssinfo(struct inode *cpfile, __u64 *cnop, */ ssize_t nilfs_cpfile_get_cpinfo(struct inode *cpfile, __u64 *cnop, int mode, - struct nilfs_cpinfo *ci, size_t nci) + void *buf, unsigned cisz, size_t nci) { switch (mode) { case NILFS_CHECKPOINT: - return nilfs_cpfile_do_get_cpinfo(cpfile, cnop, ci, nci); + return nilfs_cpfile_do_get_cpinfo(cpfile, cnop, buf, cisz, nci); case NILFS_SNAPSHOT: - return nilfs_cpfile_do_get_ssinfo(cpfile, cnop, ci, nci); + return nilfs_cpfile_do_get_ssinfo(cpfile, cnop, buf, cisz, nci); default: return -EINVAL; } @@ -535,7 +544,7 @@ int nilfs_cpfile_delete_checkpoint(struct inode *cpfile, __u64 cno) ssize_t nci; int ret; - nci = nilfs_cpfile_do_get_cpinfo(cpfile, &tcno, &ci, 1); + nci = nilfs_cpfile_do_get_cpinfo(cpfile, &tcno, &ci, sizeof(ci), 1); if (nci < 0) return nci; else if (nci == 0 || ci.ci_cno != cno) |