linux/fs/nilfs2/super.c
Ryusuke Konishi 42560f9c92 nilfs2: fix sysfs interface lifetime
The current nilfs2 sysfs support has issues with the timing of creation
and deletion of sysfs entries, potentially leading to null pointer
dereferences, use-after-free, and lockdep warnings.

Some of the sysfs attributes for nilfs2 per-filesystem instance refer to
metadata file "cpfile", "sufile", or "dat", but
nilfs_sysfs_create_device_group that creates those attributes is executed
before the inodes for these metadata files are loaded, and
nilfs_sysfs_delete_device_group which deletes these sysfs entries is
called after releasing their metadata file inodes.

Therefore, access to some of these sysfs attributes may occur outside of
the lifetime of these metadata files, resulting in inode NULL pointer
dereferences or use-after-free.

In addition, the call to nilfs_sysfs_create_device_group() is made during
the locking period of the semaphore "ns_sem" of nilfs object, so the
shrinker call caused by the memory allocation for the sysfs entries, may
derive lock dependencies "ns_sem" -> (shrinker) -> "locks acquired in
nilfs_evict_inode()".

Since nilfs2 may acquire "ns_sem" deep in the call stack holding other
locks via its error handler __nilfs_error(), this causes lockdep to report
circular locking.  This is a false positive and no circular locking
actually occurs as no inodes exist yet when
nilfs_sysfs_create_device_group() is called.  Fortunately, the lockdep
warnings can be resolved by simply moving the call to
nilfs_sysfs_create_device_group() out of "ns_sem".

This fixes these sysfs issues by revising where the device's sysfs
interface is created/deleted and keeping its lifetime within the lifetime
of the metadata files above.

Link: https://lkml.kernel.org/r/20230330205515.6167-1-konishi.ryusuke@gmail.com
Fixes: dd70edbde2 ("nilfs2: integrate sysfs support into driver")
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Reported-by: syzbot+979fa7f9c0d086fdc282@syzkaller.appspotmail.com
  Link: https://lkml.kernel.org/r/0000000000003414b505f7885f7e@google.com
Reported-by: syzbot+5b7d542076d9bddc3c6a@syzkaller.appspotmail.com
  Link: https://lkml.kernel.org/r/0000000000006ac86605f5f44eb9@google.com
Cc: Viacheslav Dubeyko <slava@dubeyko.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-04-05 18:06:24 -07:00

1482 lines
35 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* NILFS module and super block management.
*
* Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
*
* Written by Ryusuke Konishi.
*/
/*
* linux/fs/ext2/super.c
*
* Copyright (C) 1992, 1993, 1994, 1995
* Remy Card (card@masi.ibp.fr)
* Laboratoire MASI - Institut Blaise Pascal
* Universite Pierre et Marie Curie (Paris VI)
*
* from
*
* linux/fs/minix/inode.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
*
* Big-endian to little-endian byte-swapping/bitmaps by
* David S. Miller (davem@caip.rutgers.edu), 1995
*/
#include <linux/module.h>
#include <linux/string.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/blkdev.h>
#include <linux/parser.h>
#include <linux/crc32.h>
#include <linux/vfs.h>
#include <linux/writeback.h>
#include <linux/seq_file.h>
#include <linux/mount.h>
#include "nilfs.h"
#include "export.h"
#include "mdt.h"
#include "alloc.h"
#include "btree.h"
#include "btnode.h"
#include "page.h"
#include "cpfile.h"
#include "sufile.h" /* nilfs_sufile_resize(), nilfs_sufile_set_alloc_range() */
#include "ifile.h"
#include "dat.h"
#include "segment.h"
#include "segbuf.h"
MODULE_AUTHOR("NTT Corp.");
MODULE_DESCRIPTION("A New Implementation of the Log-structured Filesystem "
"(NILFS)");
MODULE_LICENSE("GPL");
static struct kmem_cache *nilfs_inode_cachep;
struct kmem_cache *nilfs_transaction_cachep;
struct kmem_cache *nilfs_segbuf_cachep;
struct kmem_cache *nilfs_btree_path_cache;
static int nilfs_setup_super(struct super_block *sb, int is_mount);
static int nilfs_remount(struct super_block *sb, int *flags, char *data);
void __nilfs_msg(struct super_block *sb, const char *fmt, ...)
{
struct va_format vaf;
va_list args;
int level;
va_start(args, fmt);
level = printk_get_level(fmt);
vaf.fmt = printk_skip_level(fmt);
vaf.va = &args;
if (sb)
printk("%c%cNILFS (%s): %pV\n",
KERN_SOH_ASCII, level, sb->s_id, &vaf);
else
printk("%c%cNILFS: %pV\n",
KERN_SOH_ASCII, level, &vaf);
va_end(args);
}
static void nilfs_set_error(struct super_block *sb)
{
struct the_nilfs *nilfs = sb->s_fs_info;
struct nilfs_super_block **sbp;
down_write(&nilfs->ns_sem);
if (!(nilfs->ns_mount_state & NILFS_ERROR_FS)) {
nilfs->ns_mount_state |= NILFS_ERROR_FS;
sbp = nilfs_prepare_super(sb, 0);
if (likely(sbp)) {
sbp[0]->s_state |= cpu_to_le16(NILFS_ERROR_FS);
if (sbp[1])
sbp[1]->s_state |= cpu_to_le16(NILFS_ERROR_FS);
nilfs_commit_super(sb, NILFS_SB_COMMIT_ALL);
}
}
up_write(&nilfs->ns_sem);
}
/**
* __nilfs_error() - report failure condition on a filesystem
*
* __nilfs_error() sets an ERROR_FS flag on the superblock as well as
* reporting an error message. This function should be called when
* NILFS detects incoherences or defects of meta data on disk.
*
* This implements the body of nilfs_error() macro. Normally,
* nilfs_error() should be used. As for sustainable errors such as a
* single-shot I/O error, nilfs_err() should be used instead.
*
* Callers should not add a trailing newline since this will do it.
*/
void __nilfs_error(struct super_block *sb, const char *function,
const char *fmt, ...)
{
struct the_nilfs *nilfs = sb->s_fs_info;
struct va_format vaf;
va_list args;
va_start(args, fmt);
vaf.fmt = fmt;
vaf.va = &args;
printk(KERN_CRIT "NILFS error (device %s): %s: %pV\n",
sb->s_id, function, &vaf);
va_end(args);
if (!sb_rdonly(sb)) {
nilfs_set_error(sb);
if (nilfs_test_opt(nilfs, ERRORS_RO)) {
printk(KERN_CRIT "Remounting filesystem read-only\n");
sb->s_flags |= SB_RDONLY;
}
}
if (nilfs_test_opt(nilfs, ERRORS_PANIC))
panic("NILFS (device %s): panic forced after error\n",
sb->s_id);
}
struct inode *nilfs_alloc_inode(struct super_block *sb)
{
struct nilfs_inode_info *ii;
ii = alloc_inode_sb(sb, nilfs_inode_cachep, GFP_NOFS);
if (!ii)
return NULL;
ii->i_bh = NULL;
ii->i_state = 0;
ii->i_cno = 0;
ii->i_assoc_inode = NULL;
ii->i_bmap = &ii->i_bmap_data;
return &ii->vfs_inode;
}
static void nilfs_free_inode(struct inode *inode)
{
if (nilfs_is_metadata_file_inode(inode))
nilfs_mdt_destroy(inode);
kmem_cache_free(nilfs_inode_cachep, NILFS_I(inode));
}
static int nilfs_sync_super(struct super_block *sb, int flag)
{
struct the_nilfs *nilfs = sb->s_fs_info;
int err;
retry:
set_buffer_dirty(nilfs->ns_sbh[0]);
if (nilfs_test_opt(nilfs, BARRIER)) {
err = __sync_dirty_buffer(nilfs->ns_sbh[0],
REQ_SYNC | REQ_PREFLUSH | REQ_FUA);
} else {
err = sync_dirty_buffer(nilfs->ns_sbh[0]);
}
if (unlikely(err)) {
nilfs_err(sb, "unable to write superblock: err=%d", err);
if (err == -EIO && nilfs->ns_sbh[1]) {
/*
* sbp[0] points to newer log than sbp[1],
* so copy sbp[0] to sbp[1] to take over sbp[0].
*/
memcpy(nilfs->ns_sbp[1], nilfs->ns_sbp[0],
nilfs->ns_sbsize);
nilfs_fall_back_super_block(nilfs);
goto retry;
}
} else {
struct nilfs_super_block *sbp = nilfs->ns_sbp[0];
nilfs->ns_sbwcount++;
/*
* The latest segment becomes trailable from the position
* written in superblock.
*/
clear_nilfs_discontinued(nilfs);
/* update GC protection for recent segments */
if (nilfs->ns_sbh[1]) {
if (flag == NILFS_SB_COMMIT_ALL) {
set_buffer_dirty(nilfs->ns_sbh[1]);
if (sync_dirty_buffer(nilfs->ns_sbh[1]) < 0)
goto out;
}
if (le64_to_cpu(nilfs->ns_sbp[1]->s_last_cno) <
le64_to_cpu(nilfs->ns_sbp[0]->s_last_cno))
sbp = nilfs->ns_sbp[1];
}
spin_lock(&nilfs->ns_last_segment_lock);
nilfs->ns_prot_seq = le64_to_cpu(sbp->s_last_seq);
spin_unlock(&nilfs->ns_last_segment_lock);
}
out:
return err;
}
void nilfs_set_log_cursor(struct nilfs_super_block *sbp,
struct the_nilfs *nilfs)
{
sector_t nfreeblocks;
/* nilfs->ns_sem must be locked by the caller. */
nilfs_count_free_blocks(nilfs, &nfreeblocks);
sbp->s_free_blocks_count = cpu_to_le64(nfreeblocks);
spin_lock(&nilfs->ns_last_segment_lock);
sbp->s_last_seq = cpu_to_le64(nilfs->ns_last_seq);
sbp->s_last_pseg = cpu_to_le64(nilfs->ns_last_pseg);
sbp->s_last_cno = cpu_to_le64(nilfs->ns_last_cno);
spin_unlock(&nilfs->ns_last_segment_lock);
}
struct nilfs_super_block **nilfs_prepare_super(struct super_block *sb,
int flip)
{
struct the_nilfs *nilfs = sb->s_fs_info;
struct nilfs_super_block **sbp = nilfs->ns_sbp;
/* nilfs->ns_sem must be locked by the caller. */
if (sbp[0]->s_magic != cpu_to_le16(NILFS_SUPER_MAGIC)) {
if (sbp[1] &&
sbp[1]->s_magic == cpu_to_le16(NILFS_SUPER_MAGIC)) {
memcpy(sbp[0], sbp[1], nilfs->ns_sbsize);
} else {
nilfs_crit(sb, "superblock broke");
return NULL;
}
} else if (sbp[1] &&
sbp[1]->s_magic != cpu_to_le16(NILFS_SUPER_MAGIC)) {
memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
}
if (flip && sbp[1])
nilfs_swap_super_block(nilfs);
return sbp;
}
int nilfs_commit_super(struct super_block *sb, int flag)
{
struct the_nilfs *nilfs = sb->s_fs_info;
struct nilfs_super_block **sbp = nilfs->ns_sbp;
time64_t t;
/* nilfs->ns_sem must be locked by the caller. */
t = ktime_get_real_seconds();
nilfs->ns_sbwtime = t;
sbp[0]->s_wtime = cpu_to_le64(t);
sbp[0]->s_sum = 0;
sbp[0]->s_sum = cpu_to_le32(crc32_le(nilfs->ns_crc_seed,
(unsigned char *)sbp[0],
nilfs->ns_sbsize));
if (flag == NILFS_SB_COMMIT_ALL && sbp[1]) {
sbp[1]->s_wtime = sbp[0]->s_wtime;
sbp[1]->s_sum = 0;
sbp[1]->s_sum = cpu_to_le32(crc32_le(nilfs->ns_crc_seed,
(unsigned char *)sbp[1],
nilfs->ns_sbsize));
}
clear_nilfs_sb_dirty(nilfs);
nilfs->ns_flushed_device = 1;
/* make sure store to ns_flushed_device cannot be reordered */
smp_wmb();
return nilfs_sync_super(sb, flag);
}
/**
* nilfs_cleanup_super() - write filesystem state for cleanup
* @sb: super block instance to be unmounted or degraded to read-only
*
* This function restores state flags in the on-disk super block.
* This will set "clean" flag (i.e. NILFS_VALID_FS) unless the
* filesystem was not clean previously.
*/
int nilfs_cleanup_super(struct super_block *sb)
{
struct the_nilfs *nilfs = sb->s_fs_info;
struct nilfs_super_block **sbp;
int flag = NILFS_SB_COMMIT;
int ret = -EIO;
sbp = nilfs_prepare_super(sb, 0);
if (sbp) {
sbp[0]->s_state = cpu_to_le16(nilfs->ns_mount_state);
nilfs_set_log_cursor(sbp[0], nilfs);
if (sbp[1] && sbp[0]->s_last_cno == sbp[1]->s_last_cno) {
/*
* make the "clean" flag also to the opposite
* super block if both super blocks point to
* the same checkpoint.
*/
sbp[1]->s_state = sbp[0]->s_state;
flag = NILFS_SB_COMMIT_ALL;
}
ret = nilfs_commit_super(sb, flag);
}
return ret;
}
/**
* nilfs_move_2nd_super - relocate secondary super block
* @sb: super block instance
* @sb2off: new offset of the secondary super block (in bytes)
*/
static int nilfs_move_2nd_super(struct super_block *sb, loff_t sb2off)
{
struct the_nilfs *nilfs = sb->s_fs_info;
struct buffer_head *nsbh;
struct nilfs_super_block *nsbp;
sector_t blocknr, newblocknr;
unsigned long offset;
int sb2i; /* array index of the secondary superblock */
int ret = 0;
/* nilfs->ns_sem must be locked by the caller. */
if (nilfs->ns_sbh[1] &&
nilfs->ns_sbh[1]->b_blocknr > nilfs->ns_first_data_block) {
sb2i = 1;
blocknr = nilfs->ns_sbh[1]->b_blocknr;
} else if (nilfs->ns_sbh[0]->b_blocknr > nilfs->ns_first_data_block) {
sb2i = 0;
blocknr = nilfs->ns_sbh[0]->b_blocknr;
} else {
sb2i = -1;
blocknr = 0;
}
if (sb2i >= 0 && (u64)blocknr << nilfs->ns_blocksize_bits == sb2off)
goto out; /* super block location is unchanged */
/* Get new super block buffer */
newblocknr = sb2off >> nilfs->ns_blocksize_bits;
offset = sb2off & (nilfs->ns_blocksize - 1);
nsbh = sb_getblk(sb, newblocknr);
if (!nsbh) {
nilfs_warn(sb,
"unable to move secondary superblock to block %llu",
(unsigned long long)newblocknr);
ret = -EIO;
goto out;
}
nsbp = (void *)nsbh->b_data + offset;
memset(nsbp, 0, nilfs->ns_blocksize);
if (sb2i >= 0) {
memcpy(nsbp, nilfs->ns_sbp[sb2i], nilfs->ns_sbsize);
brelse(nilfs->ns_sbh[sb2i]);
nilfs->ns_sbh[sb2i] = nsbh;
nilfs->ns_sbp[sb2i] = nsbp;
} else if (nilfs->ns_sbh[0]->b_blocknr < nilfs->ns_first_data_block) {
/* secondary super block will be restored to index 1 */
nilfs->ns_sbh[1] = nsbh;
nilfs->ns_sbp[1] = nsbp;
} else {
brelse(nsbh);
}
out:
return ret;
}
/**
* nilfs_resize_fs - resize the filesystem
* @sb: super block instance
* @newsize: new size of the filesystem (in bytes)
*/
int nilfs_resize_fs(struct super_block *sb, __u64 newsize)
{
struct the_nilfs *nilfs = sb->s_fs_info;
struct nilfs_super_block **sbp;
__u64 devsize, newnsegs;
loff_t sb2off;
int ret;
ret = -ERANGE;
devsize = bdev_nr_bytes(sb->s_bdev);
if (newsize > devsize)
goto out;
/*
* Prevent underflow in second superblock position calculation.
* The exact minimum size check is done in nilfs_sufile_resize().
*/
if (newsize < 4096) {
ret = -ENOSPC;
goto out;
}
/*
* Write lock is required to protect some functions depending
* on the number of segments, the number of reserved segments,
* and so forth.
*/
down_write(&nilfs->ns_segctor_sem);
sb2off = NILFS_SB2_OFFSET_BYTES(newsize);
newnsegs = sb2off >> nilfs->ns_blocksize_bits;
do_div(newnsegs, nilfs->ns_blocks_per_segment);
ret = nilfs_sufile_resize(nilfs->ns_sufile, newnsegs);
up_write(&nilfs->ns_segctor_sem);
if (ret < 0)
goto out;
ret = nilfs_construct_segment(sb);
if (ret < 0)
goto out;
down_write(&nilfs->ns_sem);
nilfs_move_2nd_super(sb, sb2off);
ret = -EIO;
sbp = nilfs_prepare_super(sb, 0);
if (likely(sbp)) {
nilfs_set_log_cursor(sbp[0], nilfs);
/*
* Drop NILFS_RESIZE_FS flag for compatibility with
* mount-time resize which may be implemented in a
* future release.
*/
sbp[0]->s_state = cpu_to_le16(le16_to_cpu(sbp[0]->s_state) &
~NILFS_RESIZE_FS);
sbp[0]->s_dev_size = cpu_to_le64(newsize);
sbp[0]->s_nsegments = cpu_to_le64(nilfs->ns_nsegments);
if (sbp[1])
memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
ret = nilfs_commit_super(sb, NILFS_SB_COMMIT_ALL);
}
up_write(&nilfs->ns_sem);
/*
* Reset the range of allocatable segments last. This order
* is important in the case of expansion because the secondary
* superblock must be protected from log write until migration
* completes.
*/
if (!ret)
nilfs_sufile_set_alloc_range(nilfs->ns_sufile, 0, newnsegs - 1);
out:
return ret;
}
static void nilfs_put_super(struct super_block *sb)
{
struct the_nilfs *nilfs = sb->s_fs_info;
nilfs_detach_log_writer(sb);
if (!sb_rdonly(sb)) {
down_write(&nilfs->ns_sem);
nilfs_cleanup_super(sb);
up_write(&nilfs->ns_sem);
}
nilfs_sysfs_delete_device_group(nilfs);
iput(nilfs->ns_sufile);
iput(nilfs->ns_cpfile);
iput(nilfs->ns_dat);
destroy_nilfs(nilfs);
sb->s_fs_info = NULL;
}
static int nilfs_sync_fs(struct super_block *sb, int wait)
{
struct the_nilfs *nilfs = sb->s_fs_info;
struct nilfs_super_block **sbp;
int err = 0;
/* This function is called when super block should be written back */
if (wait)
err = nilfs_construct_segment(sb);
down_write(&nilfs->ns_sem);
if (nilfs_sb_dirty(nilfs)) {
sbp = nilfs_prepare_super(sb, nilfs_sb_will_flip(nilfs));
if (likely(sbp)) {
nilfs_set_log_cursor(sbp[0], nilfs);
nilfs_commit_super(sb, NILFS_SB_COMMIT);
}
}
up_write(&nilfs->ns_sem);
if (!err)
err = nilfs_flush_device(nilfs);
return err;
}
int nilfs_attach_checkpoint(struct super_block *sb, __u64 cno, int curr_mnt,
struct nilfs_root **rootp)
{
struct the_nilfs *nilfs = sb->s_fs_info;
struct nilfs_root *root;
struct nilfs_checkpoint *raw_cp;
struct buffer_head *bh_cp;
int err = -ENOMEM;
root = nilfs_find_or_create_root(
nilfs, curr_mnt ? NILFS_CPTREE_CURRENT_CNO : cno);
if (!root)
return err;
if (root->ifile)
goto reuse; /* already attached checkpoint */
down_read(&nilfs->ns_segctor_sem);
err = nilfs_cpfile_get_checkpoint(nilfs->ns_cpfile, cno, 0, &raw_cp,
&bh_cp);
up_read(&nilfs->ns_segctor_sem);
if (unlikely(err)) {
if (err == -ENOENT || err == -EINVAL) {
nilfs_err(sb,
"Invalid checkpoint (checkpoint number=%llu)",
(unsigned long long)cno);
err = -EINVAL;
}
goto failed;
}
err = nilfs_ifile_read(sb, root, nilfs->ns_inode_size,
&raw_cp->cp_ifile_inode, &root->ifile);
if (err)
goto failed_bh;
atomic64_set(&root->inodes_count,
le64_to_cpu(raw_cp->cp_inodes_count));
atomic64_set(&root->blocks_count,
le64_to_cpu(raw_cp->cp_blocks_count));
nilfs_cpfile_put_checkpoint(nilfs->ns_cpfile, cno, bh_cp);
reuse:
*rootp = root;
return 0;
failed_bh:
nilfs_cpfile_put_checkpoint(nilfs->ns_cpfile, cno, bh_cp);
failed:
nilfs_put_root(root);
return err;
}
static int nilfs_freeze(struct super_block *sb)
{
struct the_nilfs *nilfs = sb->s_fs_info;
int err;
if (sb_rdonly(sb))
return 0;
/* Mark super block clean */
down_write(&nilfs->ns_sem);
err = nilfs_cleanup_super(sb);
up_write(&nilfs->ns_sem);
return err;
}
static int nilfs_unfreeze(struct super_block *sb)
{
struct the_nilfs *nilfs = sb->s_fs_info;
if (sb_rdonly(sb))
return 0;
down_write(&nilfs->ns_sem);
nilfs_setup_super(sb, false);
up_write(&nilfs->ns_sem);
return 0;
}
static int nilfs_statfs(struct dentry *dentry, struct kstatfs *buf)
{
struct super_block *sb = dentry->d_sb;
struct nilfs_root *root = NILFS_I(d_inode(dentry))->i_root;
struct the_nilfs *nilfs = root->nilfs;
u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
unsigned long long blocks;
unsigned long overhead;
unsigned long nrsvblocks;
sector_t nfreeblocks;
u64 nmaxinodes, nfreeinodes;
int err;
/*
* Compute all of the segment blocks
*
* The blocks before first segment and after last segment
* are excluded.
*/
blocks = nilfs->ns_blocks_per_segment * nilfs->ns_nsegments
- nilfs->ns_first_data_block;
nrsvblocks = nilfs->ns_nrsvsegs * nilfs->ns_blocks_per_segment;
/*
* Compute the overhead
*
* When distributing meta data blocks outside segment structure,
* We must count them as the overhead.
*/
overhead = 0;
err = nilfs_count_free_blocks(nilfs, &nfreeblocks);
if (unlikely(err))
return err;
err = nilfs_ifile_count_free_inodes(root->ifile,
&nmaxinodes, &nfreeinodes);
if (unlikely(err)) {
nilfs_warn(sb, "failed to count free inodes: err=%d", err);
if (err == -ERANGE) {
/*
* If nilfs_palloc_count_max_entries() returns
* -ERANGE error code then we simply treat
* curent inodes count as maximum possible and
* zero as free inodes value.
*/
nmaxinodes = atomic64_read(&root->inodes_count);
nfreeinodes = 0;
err = 0;
} else
return err;
}
buf->f_type = NILFS_SUPER_MAGIC;
buf->f_bsize = sb->s_blocksize;
buf->f_blocks = blocks - overhead;
buf->f_bfree = nfreeblocks;
buf->f_bavail = (buf->f_bfree >= nrsvblocks) ?
(buf->f_bfree - nrsvblocks) : 0;
buf->f_files = nmaxinodes;
buf->f_ffree = nfreeinodes;
buf->f_namelen = NILFS_NAME_LEN;
buf->f_fsid = u64_to_fsid(id);
return 0;
}
static int nilfs_show_options(struct seq_file *seq, struct dentry *dentry)
{
struct super_block *sb = dentry->d_sb;
struct the_nilfs *nilfs = sb->s_fs_info;
struct nilfs_root *root = NILFS_I(d_inode(dentry))->i_root;
if (!nilfs_test_opt(nilfs, BARRIER))
seq_puts(seq, ",nobarrier");
if (root->cno != NILFS_CPTREE_CURRENT_CNO)
seq_printf(seq, ",cp=%llu", (unsigned long long)root->cno);
if (nilfs_test_opt(nilfs, ERRORS_PANIC))
seq_puts(seq, ",errors=panic");
if (nilfs_test_opt(nilfs, ERRORS_CONT))
seq_puts(seq, ",errors=continue");
if (nilfs_test_opt(nilfs, STRICT_ORDER))
seq_puts(seq, ",order=strict");
if (nilfs_test_opt(nilfs, NORECOVERY))
seq_puts(seq, ",norecovery");
if (nilfs_test_opt(nilfs, DISCARD))
seq_puts(seq, ",discard");
return 0;
}
static const struct super_operations nilfs_sops = {
.alloc_inode = nilfs_alloc_inode,
.free_inode = nilfs_free_inode,
.dirty_inode = nilfs_dirty_inode,
.evict_inode = nilfs_evict_inode,
.put_super = nilfs_put_super,
.sync_fs = nilfs_sync_fs,
.freeze_fs = nilfs_freeze,
.unfreeze_fs = nilfs_unfreeze,
.statfs = nilfs_statfs,
.remount_fs = nilfs_remount,
.show_options = nilfs_show_options
};
enum {
Opt_err_cont, Opt_err_panic, Opt_err_ro,
Opt_barrier, Opt_nobarrier, Opt_snapshot, Opt_order, Opt_norecovery,
Opt_discard, Opt_nodiscard, Opt_err,
};
static match_table_t tokens = {
{Opt_err_cont, "errors=continue"},
{Opt_err_panic, "errors=panic"},
{Opt_err_ro, "errors=remount-ro"},
{Opt_barrier, "barrier"},
{Opt_nobarrier, "nobarrier"},
{Opt_snapshot, "cp=%u"},
{Opt_order, "order=%s"},
{Opt_norecovery, "norecovery"},
{Opt_discard, "discard"},
{Opt_nodiscard, "nodiscard"},
{Opt_err, NULL}
};
static int parse_options(char *options, struct super_block *sb, int is_remount)
{
struct the_nilfs *nilfs = sb->s_fs_info;
char *p;
substring_t args[MAX_OPT_ARGS];
if (!options)
return 1;
while ((p = strsep(&options, ",")) != NULL) {
int token;
if (!*p)
continue;
token = match_token(p, tokens, args);
switch (token) {
case Opt_barrier:
nilfs_set_opt(nilfs, BARRIER);
break;
case Opt_nobarrier:
nilfs_clear_opt(nilfs, BARRIER);
break;
case Opt_order:
if (strcmp(args[0].from, "relaxed") == 0)
/* Ordered data semantics */
nilfs_clear_opt(nilfs, STRICT_ORDER);
else if (strcmp(args[0].from, "strict") == 0)
/* Strict in-order semantics */
nilfs_set_opt(nilfs, STRICT_ORDER);
else
return 0;
break;
case Opt_err_panic:
nilfs_write_opt(nilfs, ERROR_MODE, ERRORS_PANIC);
break;
case Opt_err_ro:
nilfs_write_opt(nilfs, ERROR_MODE, ERRORS_RO);
break;
case Opt_err_cont:
nilfs_write_opt(nilfs, ERROR_MODE, ERRORS_CONT);
break;
case Opt_snapshot:
if (is_remount) {
nilfs_err(sb,
"\"%s\" option is invalid for remount",
p);
return 0;
}
break;
case Opt_norecovery:
nilfs_set_opt(nilfs, NORECOVERY);
break;
case Opt_discard:
nilfs_set_opt(nilfs, DISCARD);
break;
case Opt_nodiscard:
nilfs_clear_opt(nilfs, DISCARD);
break;
default:
nilfs_err(sb, "unrecognized mount option \"%s\"", p);
return 0;
}
}
return 1;
}
static inline void
nilfs_set_default_options(struct super_block *sb,
struct nilfs_super_block *sbp)
{
struct the_nilfs *nilfs = sb->s_fs_info;
nilfs->ns_mount_opt =
NILFS_MOUNT_ERRORS_RO | NILFS_MOUNT_BARRIER;
}
static int nilfs_setup_super(struct super_block *sb, int is_mount)
{
struct the_nilfs *nilfs = sb->s_fs_info;
struct nilfs_super_block **sbp;
int max_mnt_count;
int mnt_count;
/* nilfs->ns_sem must be locked by the caller. */
sbp = nilfs_prepare_super(sb, 0);
if (!sbp)
return -EIO;
if (!is_mount)
goto skip_mount_setup;
max_mnt_count = le16_to_cpu(sbp[0]->s_max_mnt_count);
mnt_count = le16_to_cpu(sbp[0]->s_mnt_count);
if (nilfs->ns_mount_state & NILFS_ERROR_FS) {
nilfs_warn(sb, "mounting fs with errors");
#if 0
} else if (max_mnt_count >= 0 && mnt_count >= max_mnt_count) {
nilfs_warn(sb, "maximal mount count reached");
#endif
}
if (!max_mnt_count)
sbp[0]->s_max_mnt_count = cpu_to_le16(NILFS_DFL_MAX_MNT_COUNT);
sbp[0]->s_mnt_count = cpu_to_le16(mnt_count + 1);
sbp[0]->s_mtime = cpu_to_le64(ktime_get_real_seconds());
skip_mount_setup:
sbp[0]->s_state =
cpu_to_le16(le16_to_cpu(sbp[0]->s_state) & ~NILFS_VALID_FS);
/* synchronize sbp[1] with sbp[0] */
if (sbp[1])
memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
return nilfs_commit_super(sb, NILFS_SB_COMMIT_ALL);
}
struct nilfs_super_block *nilfs_read_super_block(struct super_block *sb,
u64 pos, int blocksize,
struct buffer_head **pbh)
{
unsigned long long sb_index = pos;
unsigned long offset;
offset = do_div(sb_index, blocksize);
*pbh = sb_bread(sb, sb_index);
if (!*pbh)
return NULL;
return (struct nilfs_super_block *)((char *)(*pbh)->b_data + offset);
}
int nilfs_store_magic_and_option(struct super_block *sb,
struct nilfs_super_block *sbp,
char *data)
{
struct the_nilfs *nilfs = sb->s_fs_info;
sb->s_magic = le16_to_cpu(sbp->s_magic);
/* FS independent flags */
#ifdef NILFS_ATIME_DISABLE
sb->s_flags |= SB_NOATIME;
#endif
nilfs_set_default_options(sb, sbp);
nilfs->ns_resuid = le16_to_cpu(sbp->s_def_resuid);
nilfs->ns_resgid = le16_to_cpu(sbp->s_def_resgid);
nilfs->ns_interval = le32_to_cpu(sbp->s_c_interval);
nilfs->ns_watermark = le32_to_cpu(sbp->s_c_block_max);
return !parse_options(data, sb, 0) ? -EINVAL : 0;
}
int nilfs_check_feature_compatibility(struct super_block *sb,
struct nilfs_super_block *sbp)
{
__u64 features;
features = le64_to_cpu(sbp->s_feature_incompat) &
~NILFS_FEATURE_INCOMPAT_SUPP;
if (features) {
nilfs_err(sb,
"couldn't mount because of unsupported optional features (%llx)",
(unsigned long long)features);
return -EINVAL;
}
features = le64_to_cpu(sbp->s_feature_compat_ro) &
~NILFS_FEATURE_COMPAT_RO_SUPP;
if (!sb_rdonly(sb) && features) {
nilfs_err(sb,
"couldn't mount RDWR because of unsupported optional features (%llx)",
(unsigned long long)features);
return -EINVAL;
}
return 0;
}
static int nilfs_get_root_dentry(struct super_block *sb,
struct nilfs_root *root,
struct dentry **root_dentry)
{
struct inode *inode;
struct dentry *dentry;
int ret = 0;
inode = nilfs_iget(sb, root, NILFS_ROOT_INO);
if (IS_ERR(inode)) {
ret = PTR_ERR(inode);
nilfs_err(sb, "error %d getting root inode", ret);
goto out;
}
if (!S_ISDIR(inode->i_mode) || !inode->i_blocks || !inode->i_size) {
iput(inode);
nilfs_err(sb, "corrupt root inode");
ret = -EINVAL;
goto out;
}
if (root->cno == NILFS_CPTREE_CURRENT_CNO) {
dentry = d_find_alias(inode);
if (!dentry) {
dentry = d_make_root(inode);
if (!dentry) {
ret = -ENOMEM;
goto failed_dentry;
}
} else {
iput(inode);
}
} else {
dentry = d_obtain_root(inode);
if (IS_ERR(dentry)) {
ret = PTR_ERR(dentry);
goto failed_dentry;
}
}
*root_dentry = dentry;
out:
return ret;
failed_dentry:
nilfs_err(sb, "error %d getting root dentry", ret);
goto out;
}
static int nilfs_attach_snapshot(struct super_block *s, __u64 cno,
struct dentry **root_dentry)
{
struct the_nilfs *nilfs = s->s_fs_info;
struct nilfs_root *root;
int ret;
mutex_lock(&nilfs->ns_snapshot_mount_mutex);
down_read(&nilfs->ns_segctor_sem);
ret = nilfs_cpfile_is_snapshot(nilfs->ns_cpfile, cno);
up_read(&nilfs->ns_segctor_sem);
if (ret < 0) {
ret = (ret == -ENOENT) ? -EINVAL : ret;
goto out;
} else if (!ret) {
nilfs_err(s,
"The specified checkpoint is not a snapshot (checkpoint number=%llu)",
(unsigned long long)cno);
ret = -EINVAL;
goto out;
}
ret = nilfs_attach_checkpoint(s, cno, false, &root);
if (ret) {
nilfs_err(s,
"error %d while loading snapshot (checkpoint number=%llu)",
ret, (unsigned long long)cno);
goto out;
}
ret = nilfs_get_root_dentry(s, root, root_dentry);
nilfs_put_root(root);
out:
mutex_unlock(&nilfs->ns_snapshot_mount_mutex);
return ret;
}
/**
* nilfs_tree_is_busy() - try to shrink dentries of a checkpoint
* @root_dentry: root dentry of the tree to be shrunk
*
* This function returns true if the tree was in-use.
*/
static bool nilfs_tree_is_busy(struct dentry *root_dentry)
{
shrink_dcache_parent(root_dentry);
return d_count(root_dentry) > 1;
}
int nilfs_checkpoint_is_mounted(struct super_block *sb, __u64 cno)
{
struct the_nilfs *nilfs = sb->s_fs_info;
struct nilfs_root *root;
struct inode *inode;
struct dentry *dentry;
int ret;
if (cno > nilfs->ns_cno)
return false;
if (cno >= nilfs_last_cno(nilfs))
return true; /* protect recent checkpoints */
ret = false;
root = nilfs_lookup_root(nilfs, cno);
if (root) {
inode = nilfs_ilookup(sb, root, NILFS_ROOT_INO);
if (inode) {
dentry = d_find_alias(inode);
if (dentry) {
ret = nilfs_tree_is_busy(dentry);
dput(dentry);
}
iput(inode);
}
nilfs_put_root(root);
}
return ret;
}
/**
* nilfs_fill_super() - initialize a super block instance
* @sb: super_block
* @data: mount options
* @silent: silent mode flag
*
* This function is called exclusively by nilfs->ns_mount_mutex.
* So, the recovery process is protected from other simultaneous mounts.
*/
static int
nilfs_fill_super(struct super_block *sb, void *data, int silent)
{
struct the_nilfs *nilfs;
struct nilfs_root *fsroot;
__u64 cno;
int err;
nilfs = alloc_nilfs(sb);
if (!nilfs)
return -ENOMEM;
sb->s_fs_info = nilfs;
err = init_nilfs(nilfs, sb, (char *)data);
if (err)
goto failed_nilfs;
sb->s_op = &nilfs_sops;
sb->s_export_op = &nilfs_export_ops;
sb->s_root = NULL;
sb->s_time_gran = 1;
sb->s_max_links = NILFS_LINK_MAX;
sb->s_bdi = bdi_get(sb->s_bdev->bd_disk->bdi);
err = load_nilfs(nilfs, sb);
if (err)
goto failed_nilfs;
cno = nilfs_last_cno(nilfs);
err = nilfs_attach_checkpoint(sb, cno, true, &fsroot);
if (err) {
nilfs_err(sb,
"error %d while loading last checkpoint (checkpoint number=%llu)",
err, (unsigned long long)cno);
goto failed_unload;
}
if (!sb_rdonly(sb)) {
err = nilfs_attach_log_writer(sb, fsroot);
if (err)
goto failed_checkpoint;
}
err = nilfs_get_root_dentry(sb, fsroot, &sb->s_root);
if (err)
goto failed_segctor;
nilfs_put_root(fsroot);
if (!sb_rdonly(sb)) {
down_write(&nilfs->ns_sem);
nilfs_setup_super(sb, true);
up_write(&nilfs->ns_sem);
}
return 0;
failed_segctor:
nilfs_detach_log_writer(sb);
failed_checkpoint:
nilfs_put_root(fsroot);
failed_unload:
nilfs_sysfs_delete_device_group(nilfs);
iput(nilfs->ns_sufile);
iput(nilfs->ns_cpfile);
iput(nilfs->ns_dat);
failed_nilfs:
destroy_nilfs(nilfs);
return err;
}
static int nilfs_remount(struct super_block *sb, int *flags, char *data)
{
struct the_nilfs *nilfs = sb->s_fs_info;
unsigned long old_sb_flags;
unsigned long old_mount_opt;
int err;
sync_filesystem(sb);
old_sb_flags = sb->s_flags;
old_mount_opt = nilfs->ns_mount_opt;
if (!parse_options(data, sb, 1)) {
err = -EINVAL;
goto restore_opts;
}
sb->s_flags = (sb->s_flags & ~SB_POSIXACL);
err = -EINVAL;
if (!nilfs_valid_fs(nilfs)) {
nilfs_warn(sb,
"couldn't remount because the filesystem is in an incomplete recovery state");
goto restore_opts;
}
if ((bool)(*flags & SB_RDONLY) == sb_rdonly(sb))
goto out;
if (*flags & SB_RDONLY) {
sb->s_flags |= SB_RDONLY;
/*
* Remounting a valid RW partition RDONLY, so set
* the RDONLY flag and then mark the partition as valid again.
*/
down_write(&nilfs->ns_sem);
nilfs_cleanup_super(sb);
up_write(&nilfs->ns_sem);
} else {
__u64 features;
struct nilfs_root *root;
/*
* Mounting a RDONLY partition read-write, so reread and
* store the current valid flag. (It may have been changed
* by fsck since we originally mounted the partition.)
*/
down_read(&nilfs->ns_sem);
features = le64_to_cpu(nilfs->ns_sbp[0]->s_feature_compat_ro) &
~NILFS_FEATURE_COMPAT_RO_SUPP;
up_read(&nilfs->ns_sem);
if (features) {
nilfs_warn(sb,
"couldn't remount RDWR because of unsupported optional features (%llx)",
(unsigned long long)features);
err = -EROFS;
goto restore_opts;
}
sb->s_flags &= ~SB_RDONLY;
root = NILFS_I(d_inode(sb->s_root))->i_root;
err = nilfs_attach_log_writer(sb, root);
if (err)
goto restore_opts;
down_write(&nilfs->ns_sem);
nilfs_setup_super(sb, true);
up_write(&nilfs->ns_sem);
}
out:
return 0;
restore_opts:
sb->s_flags = old_sb_flags;
nilfs->ns_mount_opt = old_mount_opt;
return err;
}
struct nilfs_super_data {
struct block_device *bdev;
__u64 cno;
int flags;
};
static int nilfs_parse_snapshot_option(const char *option,
const substring_t *arg,
struct nilfs_super_data *sd)
{
unsigned long long val;
const char *msg = NULL;
int err;
if (!(sd->flags & SB_RDONLY)) {
msg = "read-only option is not specified";
goto parse_error;
}
err = kstrtoull(arg->from, 0, &val);
if (err) {
if (err == -ERANGE)
msg = "too large checkpoint number";
else
msg = "malformed argument";
goto parse_error;
} else if (val == 0) {
msg = "invalid checkpoint number 0";
goto parse_error;
}
sd->cno = val;
return 0;
parse_error:
nilfs_err(NULL, "invalid option \"%s\": %s", option, msg);
return 1;
}
/**
* nilfs_identify - pre-read mount options needed to identify mount instance
* @data: mount options
* @sd: nilfs_super_data
*/
static int nilfs_identify(char *data, struct nilfs_super_data *sd)
{
char *p, *options = data;
substring_t args[MAX_OPT_ARGS];
int token;
int ret = 0;
do {
p = strsep(&options, ",");
if (p != NULL && *p) {
token = match_token(p, tokens, args);
if (token == Opt_snapshot)
ret = nilfs_parse_snapshot_option(p, &args[0],
sd);
}
if (!options)
break;
BUG_ON(options == data);
*(options - 1) = ',';
} while (!ret);
return ret;
}
static int nilfs_set_bdev_super(struct super_block *s, void *data)
{
s->s_bdev = data;
s->s_dev = s->s_bdev->bd_dev;
return 0;
}
static int nilfs_test_bdev_super(struct super_block *s, void *data)
{
return (void *)s->s_bdev == data;
}
static struct dentry *
nilfs_mount(struct file_system_type *fs_type, int flags,
const char *dev_name, void *data)
{
struct nilfs_super_data sd;
struct super_block *s;
fmode_t mode = FMODE_READ | FMODE_EXCL;
struct dentry *root_dentry;
int err, s_new = false;
if (!(flags & SB_RDONLY))
mode |= FMODE_WRITE;
sd.bdev = blkdev_get_by_path(dev_name, mode, fs_type);
if (IS_ERR(sd.bdev))
return ERR_CAST(sd.bdev);
sd.cno = 0;
sd.flags = flags;
if (nilfs_identify((char *)data, &sd)) {
err = -EINVAL;
goto failed;
}
/*
* once the super is inserted into the list by sget, s_umount
* will protect the lockfs code from trying to start a snapshot
* while we are mounting
*/
mutex_lock(&sd.bdev->bd_fsfreeze_mutex);
if (sd.bdev->bd_fsfreeze_count > 0) {
mutex_unlock(&sd.bdev->bd_fsfreeze_mutex);
err = -EBUSY;
goto failed;
}
s = sget(fs_type, nilfs_test_bdev_super, nilfs_set_bdev_super, flags,
sd.bdev);
mutex_unlock(&sd.bdev->bd_fsfreeze_mutex);
if (IS_ERR(s)) {
err = PTR_ERR(s);
goto failed;
}
if (!s->s_root) {
s_new = true;
/* New superblock instance created */
s->s_mode = mode;
snprintf(s->s_id, sizeof(s->s_id), "%pg", sd.bdev);
sb_set_blocksize(s, block_size(sd.bdev));
err = nilfs_fill_super(s, data, flags & SB_SILENT ? 1 : 0);
if (err)
goto failed_super;
s->s_flags |= SB_ACTIVE;
} else if (!sd.cno) {
if (nilfs_tree_is_busy(s->s_root)) {
if ((flags ^ s->s_flags) & SB_RDONLY) {
nilfs_err(s,
"the device already has a %s mount.",
sb_rdonly(s) ? "read-only" : "read/write");
err = -EBUSY;
goto failed_super;
}
} else {
/*
* Try remount to setup mount states if the current
* tree is not mounted and only snapshots use this sb.
*/
err = nilfs_remount(s, &flags, data);
if (err)
goto failed_super;
}
}
if (sd.cno) {
err = nilfs_attach_snapshot(s, sd.cno, &root_dentry);
if (err)
goto failed_super;
} else {
root_dentry = dget(s->s_root);
}
if (!s_new)
blkdev_put(sd.bdev, mode);
return root_dentry;
failed_super:
deactivate_locked_super(s);
failed:
if (!s_new)
blkdev_put(sd.bdev, mode);
return ERR_PTR(err);
}
struct file_system_type nilfs_fs_type = {
.owner = THIS_MODULE,
.name = "nilfs2",
.mount = nilfs_mount,
.kill_sb = kill_block_super,
.fs_flags = FS_REQUIRES_DEV,
};
MODULE_ALIAS_FS("nilfs2");
static void nilfs_inode_init_once(void *obj)
{
struct nilfs_inode_info *ii = obj;
INIT_LIST_HEAD(&ii->i_dirty);
#ifdef CONFIG_NILFS_XATTR
init_rwsem(&ii->xattr_sem);
#endif
inode_init_once(&ii->vfs_inode);
}
static void nilfs_segbuf_init_once(void *obj)
{
memset(obj, 0, sizeof(struct nilfs_segment_buffer));
}
static void nilfs_destroy_cachep(void)
{
/*
* Make sure all delayed rcu free inodes are flushed before we
* destroy cache.
*/
rcu_barrier();
kmem_cache_destroy(nilfs_inode_cachep);
kmem_cache_destroy(nilfs_transaction_cachep);
kmem_cache_destroy(nilfs_segbuf_cachep);
kmem_cache_destroy(nilfs_btree_path_cache);
}
static int __init nilfs_init_cachep(void)
{
nilfs_inode_cachep = kmem_cache_create("nilfs2_inode_cache",
sizeof(struct nilfs_inode_info), 0,
SLAB_RECLAIM_ACCOUNT|SLAB_ACCOUNT,
nilfs_inode_init_once);
if (!nilfs_inode_cachep)
goto fail;
nilfs_transaction_cachep = kmem_cache_create("nilfs2_transaction_cache",
sizeof(struct nilfs_transaction_info), 0,
SLAB_RECLAIM_ACCOUNT, NULL);
if (!nilfs_transaction_cachep)
goto fail;
nilfs_segbuf_cachep = kmem_cache_create("nilfs2_segbuf_cache",
sizeof(struct nilfs_segment_buffer), 0,
SLAB_RECLAIM_ACCOUNT, nilfs_segbuf_init_once);
if (!nilfs_segbuf_cachep)
goto fail;
nilfs_btree_path_cache = kmem_cache_create("nilfs2_btree_path_cache",
sizeof(struct nilfs_btree_path) * NILFS_BTREE_LEVEL_MAX,
0, 0, NULL);
if (!nilfs_btree_path_cache)
goto fail;
return 0;
fail:
nilfs_destroy_cachep();
return -ENOMEM;
}
static int __init init_nilfs_fs(void)
{
int err;
err = nilfs_init_cachep();
if (err)
goto fail;
err = nilfs_sysfs_init();
if (err)
goto free_cachep;
err = register_filesystem(&nilfs_fs_type);
if (err)
goto deinit_sysfs_entry;
printk(KERN_INFO "NILFS version 2 loaded\n");
return 0;
deinit_sysfs_entry:
nilfs_sysfs_exit();
free_cachep:
nilfs_destroy_cachep();
fail:
return err;
}
static void __exit exit_nilfs_fs(void)
{
nilfs_destroy_cachep();
nilfs_sysfs_exit();
unregister_filesystem(&nilfs_fs_type);
}
module_init(init_nilfs_fs)
module_exit(exit_nilfs_fs)