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authorLinus Torvalds <torvalds@linux-foundation.org>2016-12-19 17:23:53 +0100
committerLinus Torvalds <torvalds@linux-foundation.org>2016-12-19 17:23:53 +0100
commite93b1cc8a8965da137ffea0b88e5f62fa1d2a9e6 (patch)
tree9757e9167daff086a314b031429d9b65a39b96bc /fs/quota
parentMerge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm (diff)
parentquota: Fix bogus warning in dquot_disable() (diff)
downloadlinux-e93b1cc8a8965da137ffea0b88e5f62fa1d2a9e6.tar.xz
linux-e93b1cc8a8965da137ffea0b88e5f62fa1d2a9e6.zip
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
Diffstat (limited to 'fs/quota')
-rw-r--r--fs/quota/dquot.c136
-rw-r--r--fs/quota/quota.c22
2 files changed, 61 insertions, 97 deletions
diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c
index 8738a0d62c09..406fed92362a 100644
--- a/fs/quota/dquot.c
+++ b/fs/quota/dquot.c
@@ -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);
diff --git a/fs/quota/quota.c b/fs/quota/quota.c
index 5acd0c4769af..07e08c7d05ca 100644
--- a/fs/quota/quota.c
+++ b/fs/quota/quota.c
@@ -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);