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Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs 

Pull quota, fsnotify and ext2 updates from Jan Kara:
 "Changes to locking of some quota operations from dedicated quota mutex
  to s_umount semaphore, a fsnotify fix and a simple ext2 fix"

* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs:
  quota: Fix bogus warning in dquot_disable()
  fsnotify: Fix possible use-after-free in inode iteration on umount
  ext2: reject inodes with negative size
  quota: Remove dqonoff_mutex
  ocfs2: Use s_umount for quota recovery protection
  quota: Remove dqonoff_mutex from dquot_scan_active()
  ocfs2: Protect periodic quota syncing with s_umount semaphore
  quota: Use s_umount protection for quota operations
  quota: Hold s_umount in exclusive mode when enabling / disabling quotas
  fs: Provide function to get superblock with exclusive s_umount
This commit is contained in:
Linus Torvalds 2016-12-19 08:23:53 -08:00
parent 45d36906e2 2700e6067c
commit e93b1cc8a8
10 changed files with 152 additions and 161 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
fs/ext2/inode.c
View File

@ -1478,6 +1478,10 @@ struct inode *ext2_iget (struct super_block *sb, unsigned long ino)
inode->i_size |= ((__u64)le32_to_cpu(raw_inode->i_size_high)) << 32;
else
ei->i_dir_acl = le32_to_cpu(raw_inode->i_dir_acl);
if (i_size_read(inode) < 0) {
ret = -EFSCORRUPTED;
goto bad_inode;
}
ei->i_dtime = 0;
inode->i_generation = le32_to_cpu(raw_inode->i_generation);
ei->i_state = 0;

45
fs/notify/inode_mark.c
View File

@ -150,12 +150,10 @@ int fsnotify_add_inode_mark(struct fsnotify_mark *mark,
*/
void fsnotify_unmount_inodes(struct super_block *sb)
{
struct inode *inode, *next_i, *need_iput = NULL;
struct inode *inode, *iput_inode = NULL;
spin_lock(&sb->s_inode_list_lock);
list_for_each_entry_safe(inode, next_i, &sb->s_inodes, i_sb_list) {
struct inode *need_iput_tmp;
list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
/*
* We cannot __iget() an inode in state I_FREEING,
* I_WILL_FREE, or I_NEW which is fine because by that point
@ -178,49 +176,24 @@ void fsnotify_unmount_inodes(struct super_block *sb)
continue;
}
need_iput_tmp = need_iput;
need_iput = NULL;
/* In case fsnotify_inode_delete() drops a reference. */
if (inode != need_iput_tmp)
__iget(inode);
else
need_iput_tmp = NULL;
__iget(inode);
spin_unlock(&inode->i_lock);
/* In case the dropping of a reference would nuke next_i. */
while (&next_i->i_sb_list != &sb->s_inodes) {
spin_lock(&next_i->i_lock);
if (!(next_i->i_state & (I_FREEING | I_WILL_FREE)) &&
atomic_read(&next_i->i_count)) {
__iget(next_i);
need_iput = next_i;
spin_unlock(&next_i->i_lock);
break;
}
spin_unlock(&next_i->i_lock);
next_i = list_next_entry(next_i, i_sb_list);
}
/*
* We can safely drop s_inode_list_lock here because either
* we actually hold references on both inode and next_i or
* end of list. Also no new inodes will be added since the
* umount has begun.
*/
spin_unlock(&sb->s_inode_list_lock);
if (need_iput_tmp)
iput(need_iput_tmp);
if (iput_inode)
iput(iput_inode);
/* for each watch, send FS_UNMOUNT and then remove it */
fsnotify(inode, FS_UNMOUNT, inode, FSNOTIFY_EVENT_INODE, NULL, 0);
fsnotify_inode_delete(inode);
iput(inode);
iput_inode = inode;
spin_lock(&sb->s_inode_list_lock);
}
spin_unlock(&sb->s_inode_list_lock);
if (iput_inode)
iput(iput_inode);
}

10
fs/ocfs2/quota_global.c
View File

@ -634,7 +634,15 @@ static void qsync_work_fn(struct work_struct *work)
dqi_sync_work.work);
struct super_block *sb = oinfo->dqi_gqinode->i_sb;
dquot_scan_active(sb, ocfs2_sync_dquot_helper, oinfo->dqi_type);
/*
* We have to be careful here not to deadlock on s_umount as umount
* disabling quotas may be in progress and it waits for this work to
* complete. If trylock fails, we'll do the sync next time...
*/
if (down_read_trylock(&sb->s_umount)) {
dquot_scan_active(sb, ocfs2_sync_dquot_helper, oinfo->dqi_type);
up_read(&sb->s_umount);
}
schedule_delayed_work(&oinfo->dqi_sync_work,
msecs_to_jiffies(oinfo->dqi_syncms));
}

11
fs/ocfs2/quota_local.c
View File

@ -454,7 +454,7 @@ out:
/* Sync changes in local quota file into global quota file and
* reinitialize local quota file.
* The function expects local quota file to be already locked and
* dqonoff_mutex locked. */
* s_umount locked in shared mode. */
static int ocfs2_recover_local_quota_file(struct inode *lqinode,
int type,
struct ocfs2_quota_recovery *rec)
@ -597,7 +597,7 @@ int ocfs2_finish_quota_recovery(struct ocfs2_super *osb,
printk(KERN_NOTICE "ocfs2: Finishing quota recovery on device (%s) for "
"slot %u\n", osb->dev_str, slot_num);
mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
down_read(&sb->s_umount);
for (type = 0; type < OCFS2_MAXQUOTAS; type++) {
if (list_empty(&(rec->r_list[type])))
continue;
@ -674,7 +674,7 @@ out_put:
break;
}
out:
mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
up_read(&sb->s_umount);
kfree(rec);
return status;
}
@ -840,7 +840,10 @@ static int ocfs2_local_free_info(struct super_block *sb, int type)
}
ocfs2_release_local_quota_bitmaps(&oinfo->dqi_chunk);
/* dqonoff_mutex protects us against racing with recovery thread... */
/*
* s_umount held in exclusive mode protects us against racing with
* recovery thread...
*/
if (oinfo->dqi_rec) {
ocfs2_free_quota_recovery(oinfo->dqi_rec);
mark_clean = 0;

1
fs/ocfs2/super.c
View File

@ -985,7 +985,6 @@ static void ocfs2_disable_quotas(struct ocfs2_super *osb)
for (type = 0; type < OCFS2_MAXQUOTAS; type++) {
if (!sb_has_quota_loaded(sb, type))
continue;
/* Cancel periodic syncing before we grab dqonoff_mutex */
oinfo = sb_dqinfo(sb, type)->dqi_priv;
cancel_delayed_work_sync(&oinfo->dqi_sync_work);
inode = igrab(sb->s_dquot.files[type]);

136
fs/quota/dquot.c
View File

@ -119,8 +119,7 @@
* spinlock to internal buffers before writing.
*
* Lock ordering (including related VFS locks) is the following:
* dqonoff_mutex > i_mutex > journal_lock > dquot->dq_lock > dqio_mutex
* dqonoff_mutex > i_mutex comes from dquot_quota_sync, dquot_enable, etc.
* s_umount > i_mutex > journal_lock > dquot->dq_lock > dqio_mutex
*/
static __cacheline_aligned_in_smp DEFINE_SPINLOCK(dq_list_lock);
@ -572,7 +571,8 @@ int dquot_scan_active(struct super_block *sb,
struct dquot *dquot, *old_dquot = NULL;
int ret = 0;
mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
WARN_ON_ONCE(!rwsem_is_locked(&sb->s_umount));
spin_lock(&dq_list_lock);
list_for_each_entry(dquot, &inuse_list, dq_inuse) {
if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags))
@ -603,7 +603,6 @@ int dquot_scan_active(struct super_block *sb,
spin_unlock(&dq_list_lock);
out:
dqput(old_dquot);
mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
return ret;
}
EXPORT_SYMBOL(dquot_scan_active);
@ -617,7 +616,8 @@ int dquot_writeback_dquots(struct super_block *sb, int type)
int cnt;
int err, ret = 0;
mutex_lock(&dqopt->dqonoff_mutex);
WARN_ON_ONCE(!rwsem_is_locked(&sb->s_umount));
for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
if (type != -1 && cnt != type)
continue;
@ -653,7 +653,6 @@ int dquot_writeback_dquots(struct super_block *sb, int type)
&& info_dirty(&dqopt->info[cnt]))
sb->dq_op->write_info(sb, cnt);
dqstats_inc(DQST_SYNCS);
mutex_unlock(&dqopt->dqonoff_mutex);
return ret;
}
@ -683,7 +682,6 @@ int dquot_quota_sync(struct super_block *sb, int type)
* Now when everything is written we can discard the pagecache so
* that userspace sees the changes.
*/
mutex_lock(&dqopt->dqonoff_mutex);
for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
if (type != -1 && cnt != type)
continue;
@ -693,7 +691,6 @@ int dquot_quota_sync(struct super_block *sb, int type)
truncate_inode_pages(&dqopt->files[cnt]->i_data, 0);
inode_unlock(dqopt->files[cnt]);
}
mutex_unlock(&dqopt->dqonoff_mutex);
return 0;
}
@ -935,7 +932,7 @@ static int dqinit_needed(struct inode *inode, int type)
return 0;
}
/* This routine is guarded by dqonoff_mutex mutex */
/* This routine is guarded by s_umount semaphore */
static void add_dquot_ref(struct super_block *sb, int type)
{
struct inode *inode, *old_inode = NULL;
@ -2050,21 +2047,13 @@ int dquot_get_next_id(struct super_block *sb, struct kqid *qid)
struct quota_info *dqopt = sb_dqopt(sb);
int err;
mutex_lock(&dqopt->dqonoff_mutex);
if (!sb_has_quota_active(sb, qid->type)) {
err = -ESRCH;
goto out;
}
if (!dqopt->ops[qid->type]->get_next_id) {
err = -ENOSYS;
goto out;
}
if (!sb_has_quota_active(sb, qid->type))
return -ESRCH;
if (!dqopt->ops[qid->type]->get_next_id)
return -ENOSYS;
mutex_lock(&dqopt->dqio_mutex);
err = dqopt->ops[qid->type]->get_next_id(sb, qid);
mutex_unlock(&dqopt->dqio_mutex);
out:
mutex_unlock(&dqopt->dqonoff_mutex);
return err;
}
EXPORT_SYMBOL(dquot_get_next_id);
@ -2107,6 +2096,10 @@ int dquot_disable(struct super_block *sb, int type, unsigned int flags)
struct quota_info *dqopt = sb_dqopt(sb);
struct inode *toputinode[MAXQUOTAS];
/* s_umount should be held in exclusive mode */
if (WARN_ON_ONCE(down_read_trylock(&sb->s_umount)))
up_read(&sb->s_umount);
/* Cannot turn off usage accounting without turning off limits, or
* suspend quotas and simultaneously turn quotas off. */
if ((flags & DQUOT_USAGE_ENABLED && !(flags & DQUOT_LIMITS_ENABLED))
@ -2114,18 +2107,14 @@ int dquot_disable(struct super_block *sb, int type, unsigned int flags)
DQUOT_USAGE_ENABLED)))
return -EINVAL;
/* We need to serialize quota_off() for device */
mutex_lock(&dqopt->dqonoff_mutex);
/*
* Skip everything if there's nothing to do. We have to do this because
* sometimes we are called when fill_super() failed and calling
* sync_fs() in such cases does no good.
*/
if (!sb_any_quota_loaded(sb)) {
mutex_unlock(&dqopt->dqonoff_mutex);
if (!sb_any_quota_loaded(sb))
return 0;
}
for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
toputinode[cnt] = NULL;
if (type != -1 && cnt != type)
@ -2179,7 +2168,6 @@ int dquot_disable(struct super_block *sb, int type, unsigned int flags)
dqopt->info[cnt].dqi_bgrace = 0;
dqopt->ops[cnt] = NULL;
}
mutex_unlock(&dqopt->dqonoff_mutex);
/* Skip syncing and setting flags if quota files are hidden */
if (dqopt->flags & DQUOT_QUOTA_SYS_FILE)
@ -2196,20 +2184,14 @@ int dquot_disable(struct super_block *sb, int type, unsigned int flags)
* must also discard the blockdev buffers so that we see the
* changes done by userspace on the next quotaon() */
for (cnt = 0; cnt < MAXQUOTAS; cnt++)
if (toputinode[cnt]) {
mutex_lock(&dqopt->dqonoff_mutex);
/* If quota was reenabled in the meantime, we have
* nothing to do */
if (!sb_has_quota_loaded(sb, cnt)) {
inode_lock(toputinode[cnt]);
toputinode[cnt]->i_flags &= ~(S_IMMUTABLE |
/* This can happen when suspending quotas on remount-ro... */
if (toputinode[cnt] && !sb_has_quota_loaded(sb, cnt)) {
inode_lock(toputinode[cnt]);
toputinode[cnt]->i_flags &= ~(S_IMMUTABLE |
S_NOATIME | S_NOQUOTA);
truncate_inode_pages(&toputinode[cnt]->i_data,
0);
inode_unlock(toputinode[cnt]);
mark_inode_dirty_sync(toputinode[cnt]);
}
mutex_unlock(&dqopt->dqonoff_mutex);
truncate_inode_pages(&toputinode[cnt]->i_data, 0);
inode_unlock(toputinode[cnt]);
mark_inode_dirty_sync(toputinode[cnt]);
}
if (sb->s_bdev)
invalidate_bdev(sb->s_bdev);
@ -2281,6 +2263,10 @@ static int vfs_load_quota_inode(struct inode *inode, int type, int format_id,
error = -EINVAL;
goto out_fmt;
}
if (sb_has_quota_loaded(sb, type)) {
error = -EBUSY;
goto out_fmt;
}
if (!(dqopt->flags & DQUOT_QUOTA_SYS_FILE)) {
/* As we bypass the pagecache we must now flush all the
@ -2292,11 +2278,6 @@ static int vfs_load_quota_inode(struct inode *inode, int type, int format_id,
sync_filesystem(sb);
invalidate_bdev(sb->s_bdev);
}
mutex_lock(&dqopt->dqonoff_mutex);
if (sb_has_quota_loaded(sb, type)) {
error = -EBUSY;
goto out_lock;
}
if (!(dqopt->flags & DQUOT_QUOTA_SYS_FILE)) {
/* We don't want quota and atime on quota files (deadlocks
@ -2317,7 +2298,7 @@ static int vfs_load_quota_inode(struct inode *inode, int type, int format_id,
error = -EIO;
dqopt->files[type] = igrab(inode);
if (!dqopt->files[type])
goto out_lock;
goto out_file_flags;
error = -EINVAL;
if (!fmt->qf_ops->check_quota_file(sb, type))
goto out_file_init;
@ -2340,14 +2321,13 @@ static int vfs_load_quota_inode(struct inode *inode, int type, int format_id,
spin_unlock(&dq_state_lock);
add_dquot_ref(sb, type);
mutex_unlock(&dqopt->dqonoff_mutex);
return 0;
out_file_init:
dqopt->files[type] = NULL;
iput(inode);
out_lock:
out_file_flags:
if (oldflags != -1) {
inode_lock(inode);
/* Set the flags back (in the case of accidental quotaon()
@ -2356,7 +2336,6 @@ out_lock:
inode->i_flags |= oldflags;
inode_unlock(inode);
}
mutex_unlock(&dqopt->dqonoff_mutex);
out_fmt:
put_quota_format(fmt);
@ -2371,15 +2350,16 @@ int dquot_resume(struct super_block *sb, int type)
int ret = 0, cnt;
unsigned int flags;
/* s_umount should be held in exclusive mode */
if (WARN_ON_ONCE(down_read_trylock(&sb->s_umount)))
up_read(&sb->s_umount);
for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
if (type != -1 && cnt != type)
continue;
mutex_lock(&dqopt->dqonoff_mutex);
if (!sb_has_quota_suspended(sb, cnt)) {
mutex_unlock(&dqopt->dqonoff_mutex);
if (!sb_has_quota_suspended(sb, cnt))
continue;
}
inode = dqopt->files[cnt];
dqopt->files[cnt] = NULL;
spin_lock(&dq_state_lock);
@ -2388,7 +2368,6 @@ int dquot_resume(struct super_block *sb, int type)
cnt);
dqopt->flags &= ~dquot_state_flag(DQUOT_STATE_FLAGS, cnt);
spin_unlock(&dq_state_lock);
mutex_unlock(&dqopt->dqonoff_mutex);
flags = dquot_generic_flag(flags, cnt);
ret = vfs_load_quota_inode(inode, cnt,
@ -2424,42 +2403,30 @@ EXPORT_SYMBOL(dquot_quota_on);
int dquot_enable(struct inode *inode, int type, int format_id,
unsigned int flags)
{
int ret = 0;
struct super_block *sb = inode->i_sb;
struct quota_info *dqopt = sb_dqopt(sb);
/* Just unsuspend quotas? */
BUG_ON(flags & DQUOT_SUSPENDED);
/* s_umount should be held in exclusive mode */
if (WARN_ON_ONCE(down_read_trylock(&sb->s_umount)))
up_read(&sb->s_umount);
if (!flags)
return 0;
/* Just updating flags needed? */
if (sb_has_quota_loaded(sb, type)) {
mutex_lock(&dqopt->dqonoff_mutex);
/* Now do a reliable test... */
if (!sb_has_quota_loaded(sb, type)) {
mutex_unlock(&dqopt->dqonoff_mutex);
goto load_quota;
}
if (flags & DQUOT_USAGE_ENABLED &&
sb_has_quota_usage_enabled(sb, type)) {
ret = -EBUSY;
goto out_lock;
}
sb_has_quota_usage_enabled(sb, type))
return -EBUSY;
if (flags & DQUOT_LIMITS_ENABLED &&
sb_has_quota_limits_enabled(sb, type)) {
ret = -EBUSY;
goto out_lock;
}
sb_has_quota_limits_enabled(sb, type))
return -EBUSY;
spin_lock(&dq_state_lock);
sb_dqopt(sb)->flags |= dquot_state_flag(flags, type);
spin_unlock(&dq_state_lock);
out_lock:
mutex_unlock(&dqopt->dqonoff_mutex);
return ret;
return 0;
}
load_quota:
return vfs_load_quota_inode(inode, type, format_id, flags);
}
EXPORT_SYMBOL(dquot_enable);
@ -2751,7 +2718,6 @@ int dquot_get_state(struct super_block *sb, struct qc_state *state)
struct quota_info *dqopt = sb_dqopt(sb);
int type;
mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
memset(state, 0, sizeof(*state));
for (type = 0; type < MAXQUOTAS; type++) {
if (!sb_has_quota_active(sb, type))
@ -2773,7 +2739,6 @@ int dquot_get_state(struct super_block *sb, struct qc_state *state)
tstate->nextents = 1; /* We don't know... */
spin_unlock(&dq_data_lock);
}
mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
return 0;
}
EXPORT_SYMBOL(dquot_get_state);
@ -2787,18 +2752,13 @@ int dquot_set_dqinfo(struct super_block *sb, int type, struct qc_info *ii)
if ((ii->i_fieldmask & QC_WARNS_MASK) ||
(ii->i_fieldmask & QC_RT_SPC_TIMER))
return -EINVAL;
mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
if (!sb_has_quota_active(sb, type)) {
err = -ESRCH;
goto out;
}
if (!sb_has_quota_active(sb, type))
return -ESRCH;
mi = sb_dqopt(sb)->info + type;
if (ii->i_fieldmask & QC_FLAGS) {
if ((ii->i_flags & QCI_ROOT_SQUASH &&
mi->dqi_format->qf_fmt_id != QFMT_VFS_OLD)) {
err = -EINVAL;
goto out;
}
mi->dqi_format->qf_fmt_id != QFMT_VFS_OLD))
return -EINVAL;
}
spin_lock(&dq_data_lock);
if (ii->i_fieldmask & QC_SPC_TIMER)
@ -2815,8 +2775,6 @@ int dquot_set_dqinfo(struct super_block *sb, int type, struct qc_info *ii)
mark_info_dirty(sb, type);
/* Force write to disk */
sb->dq_op->write_info(sb, type);
out:
mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
return err;
}
EXPORT_SYMBOL(dquot_set_dqinfo);

22
fs/quota/quota.c
View File

@ -104,13 +104,9 @@ static int quota_getfmt(struct super_block *sb, int type, void __user *addr)
{
__u32 fmt;
mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
if (!sb_has_quota_active(sb, type)) {
mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
if (!sb_has_quota_active(sb, type))
return -ESRCH;
}
fmt = sb_dqopt(sb)->info[type].dqi_format->qf_fmt_id;
mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
if (copy_to_user(addr, &fmt, sizeof(fmt)))
return -EFAULT;
return 0;
@ -789,9 +785,14 @@ static int quotactl_cmd_write(int cmd)
}
return 1;
}
#endif /* CONFIG_BLOCK */
/* Return true if quotactl command is manipulating quota on/off state */
static bool quotactl_cmd_onoff(int cmd)
{
return (cmd == Q_QUOTAON) || (cmd == Q_QUOTAOFF);
}
/*
* look up a superblock on which quota ops will be performed
* - use the name of a block device to find the superblock thereon
@ -809,7 +810,9 @@ static struct super_block *quotactl_block(const char __user *special, int cmd)
putname(tmp);
if (IS_ERR(bdev))
return ERR_CAST(bdev);
if (quotactl_cmd_write(cmd))
if (quotactl_cmd_onoff(cmd))
sb = get_super_exclusive_thawed(bdev);
else if (quotactl_cmd_write(cmd))
sb = get_super_thawed(bdev);
else
sb = get_super(bdev);
@ -872,7 +875,10 @@ SYSCALL_DEFINE4(quotactl, unsigned int, cmd, const char __user *, special,
ret = do_quotactl(sb, type, cmds, id, addr, pathp);
drop_super(sb);
if (!quotactl_cmd_onoff(cmds))
drop_super(sb);
else
drop_super_exclusive(sb);
out:
if (pathp && !IS_ERR(pathp))
path_put(pathp);

81
fs/super.c
View File

@ -244,7 +244,6 @@ static struct super_block *alloc_super(struct file_system_type *type, int flags,
mutex_init(&s->s_vfs_rename_mutex);
lockdep_set_class(&s->s_vfs_rename_mutex, &type->s_vfs_rename_key);
mutex_init(&s->s_dquot.dqio_mutex);
mutex_init(&s->s_dquot.dqonoff_mutex);
s->s_maxbytes = MAX_NON_LFS;
s->s_op = &default_op;
s->s_time_gran = 1000000000;
@ -558,6 +557,13 @@ void drop_super(struct super_block *sb)
EXPORT_SYMBOL(drop_super);
void drop_super_exclusive(struct super_block *sb)
{
up_write(&sb->s_umount);
put_super(sb);
}
EXPORT_SYMBOL(drop_super_exclusive);
/**
* iterate_supers - call function for all active superblocks
* @f: function to call
@ -628,15 +634,7 @@ void iterate_supers_type(struct file_system_type *type,
EXPORT_SYMBOL(iterate_supers_type);
/**
* get_super - get the superblock of a device
* @bdev: device to get the superblock for
*
* Scans the superblock list and finds the superblock of the file system
* mounted on the device given. %NULL is returned if no match is found.
*/
struct super_block *get_super(struct block_device *bdev)
static struct super_block *__get_super(struct block_device *bdev, bool excl)
{
struct super_block *sb;
@ -651,11 +649,17 @@ rescan:
if (sb->s_bdev == bdev) {
sb->s_count++;
spin_unlock(&sb_lock);
down_read(&sb->s_umount);
if (!excl)
down_read(&sb->s_umount);
else
down_write(&sb->s_umount);
/* still alive? */
if (sb->s_root && (sb->s_flags & MS_BORN))
return sb;
up_read(&sb->s_umount);
if (!excl)
up_read(&sb->s_umount);
else
up_write(&sb->s_umount);
/* nope, got unmounted */
spin_lock(&sb_lock);
__put_super(sb);
@ -666,8 +670,36 @@ rescan:
return NULL;
}
/**
* get_super - get the superblock of a device
* @bdev: device to get the superblock for
*
* Scans the superblock list and finds the superblock of the file system
* mounted on the device given. %NULL is returned if no match is found.
*/
struct super_block *get_super(struct block_device *bdev)
{
return __get_super(bdev, false);
}
EXPORT_SYMBOL(get_super);
static struct super_block *__get_super_thawed(struct block_device *bdev,
bool excl)
{
while (1) {
struct super_block *s = __get_super(bdev, excl);
if (!s || s->s_writers.frozen == SB_UNFROZEN)
return s;
if (!excl)
up_read(&s->s_umount);
else
up_write(&s->s_umount);
wait_event(s->s_writers.wait_unfrozen,
s->s_writers.frozen == SB_UNFROZEN);
put_super(s);
}
}
/**
* get_super_thawed - get thawed superblock of a device
* @bdev: device to get the superblock for
@ -679,18 +711,25 @@ EXPORT_SYMBOL(get_super);
*/
struct super_block *get_super_thawed(struct block_device *bdev)
{
while (1) {
struct super_block *s = get_super(bdev);
if (!s || s->s_writers.frozen == SB_UNFROZEN)
return s;
up_read(&s->s_umount);
wait_event(s->s_writers.wait_unfrozen,
s->s_writers.frozen == SB_UNFROZEN);
put_super(s);
}
return __get_super_thawed(bdev, false);
}
EXPORT_SYMBOL(get_super_thawed);
/**
* get_super_exclusive_thawed - get thawed superblock of a device
* @bdev: device to get the superblock for
*
* Scans the superblock list and finds the superblock of the file system
* mounted on the device. The superblock is returned once it is thawed
* (or immediately if it was not frozen) and s_umount semaphore is held
* in exclusive mode. %NULL is returned if no match is found.
*/
struct super_block *get_super_exclusive_thawed(struct block_device *bdev)
{
return __get_super_thawed(bdev, true);
}
EXPORT_SYMBOL(get_super_exclusive_thawed);
/**
* get_active_super - get an active reference to the superblock of a device
* @bdev: device to get the superblock for

2
include/linux/fs.h
View File

@ -2903,8 +2903,10 @@ extern void put_filesystem(struct file_system_type *fs);
extern struct file_system_type *get_fs_type(const char *name);
extern struct super_block *get_super(struct block_device *);
extern struct super_block *get_super_thawed(struct block_device *);
extern struct super_block *get_super_exclusive_thawed(struct block_device *bdev);
extern struct super_block *get_active_super(struct block_device *bdev);
extern void drop_super(struct super_block *sb);
extern void drop_super_exclusive(struct super_block *sb);
extern void iterate_supers(void (*)(struct super_block *, void *), void *);
extern void iterate_supers_type(struct file_system_type *,
void (*)(struct super_block *, void *), void *);

1
include/linux/quota.h
View File

@ -520,7 +520,6 @@ static inline void quota_send_warning(struct kqid qid, dev_t dev,
struct quota_info {
unsigned int flags; /* Flags for diskquotas on this device */
struct mutex dqio_mutex; /* lock device while I/O in progress */
struct mutex dqonoff_mutex; /* Serialize quotaon & quotaoff */
struct inode *files[MAXQUOTAS]; /* inodes of quotafiles */
struct mem_dqinfo info[MAXQUOTAS]; /* Information for each quota type */
const struct quota_format_ops *ops[MAXQUOTAS]; /* Operations for each type */