quota: Push dqio_sem down to ->read_file_info()

[sfrench/cifs-2.6.git] / fs / quota / quota_v2.c

diff --git a/fs/quota/quota_v2.c b/fs/quota/quota_v2.c
index ca71bf881ad1e33d11c1fdd10b71070c5079358d..373d7cfea5b021a5cda159abc715a78a55769302 100644 (file)
--- a/fs/quota/quota_v2.c
+++ b/fs/quota/quota_v2.c
@@ -90,29 +90,38 @@ static int v2_read_file_info(struct super_block *sb, int type)
 {
        struct v2_disk_dqinfo dinfo;
        struct v2_disk_dqheader dqhead;
-       struct mem_dqinfo *info = sb_dqinfo(sb, type);
+       struct quota_info *dqopt = sb_dqopt(sb);
+       struct mem_dqinfo *info = &dqopt->info[type];
        struct qtree_mem_dqinfo *qinfo;
        ssize_t size;
        unsigned int version;
+       int ret;
 
-       if (!v2_read_header(sb, type, &dqhead))
-               return -1;
+       down_read(&dqopt->dqio_sem);
+       if (!v2_read_header(sb, type, &dqhead)) {
+               ret = -1;
+               goto out;
+       }
        version = le32_to_cpu(dqhead.dqh_version);
        if ((info->dqi_fmt_id == QFMT_VFS_V0 && version != 0) ||
-           (info->dqi_fmt_id == QFMT_VFS_V1 && version != 1))
-               return -1;
+           (info->dqi_fmt_id == QFMT_VFS_V1 && version != 1)) {
+               ret = -1;
+               goto out;
+       }
 
        size = sb->s_op->quota_read(sb, type, (char *)&dinfo,
               sizeof(struct v2_disk_dqinfo), V2_DQINFOOFF);
        if (size != sizeof(struct v2_disk_dqinfo)) {
                quota_error(sb, "Can't read info structure");
-               return -1;
+               ret = -1;
+               goto out;
        }
        info->dqi_priv = kmalloc(sizeof(struct qtree_mem_dqinfo), GFP_NOFS);
        if (!info->dqi_priv) {
                printk(KERN_WARNING
                       "Not enough memory for quota information structure.\n");
-               return -ENOMEM;
+               ret = -ENOMEM;
+               goto out;
        }
        qinfo = info->dqi_priv;
        if (version == 0) {
@@ -147,17 +156,22 @@ static int v2_read_file_info(struct super_block *sb, int type)
                qinfo->dqi_entry_size = sizeof(struct v2r1_disk_dqblk);
                qinfo->dqi_ops = &v2r1_qtree_ops;
        }
-       return 0;
+       ret = 0;
+out:
+       up_read(&dqopt->dqio_sem);
+       return ret;
 }
 
 /* Write information header to quota file */
 static int v2_write_file_info(struct super_block *sb, int type)
 {
        struct v2_disk_dqinfo dinfo;
-       struct mem_dqinfo *info = sb_dqinfo(sb, type);
+       struct quota_info *dqopt = sb_dqopt(sb);
+       struct mem_dqinfo *info = &dqopt->info[type];
        struct qtree_mem_dqinfo *qinfo = info->dqi_priv;
        ssize_t size;
 
+       down_write(&dqopt->dqio_sem);
        spin_lock(&dq_data_lock);
        info->dqi_flags &= ~DQF_INFO_DIRTY;
        dinfo.dqi_bgrace = cpu_to_le32(info->dqi_bgrace);
@@ -170,6 +184,7 @@ static int v2_write_file_info(struct super_block *sb, int type)
        dinfo.dqi_free_entry = cpu_to_le32(qinfo->dqi_free_entry);
        size = sb->s_op->quota_write(sb, type, (char *)&dinfo,
               sizeof(struct v2_disk_dqinfo), V2_DQINFOOFF);
+       up_write(&dqopt->dqio_sem);
        if (size != sizeof(struct v2_disk_dqinfo)) {
                quota_error(sb, "Can't write info structure");
                return -1;
@@ -285,17 +300,51 @@ static int v2r1_is_id(void *dp, struct dquot *dquot)
 
 static int v2_read_dquot(struct dquot *dquot)
 {
-       return qtree_read_dquot(sb_dqinfo(dquot->dq_sb, dquot->dq_id.type)->dqi_priv, dquot);
+       struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
+       int ret;
+
+       down_read(&dqopt->dqio_sem);
+       ret = qtree_read_dquot(
+                       sb_dqinfo(dquot->dq_sb, dquot->dq_id.type)->dqi_priv,
+                       dquot);
+       up_read(&dqopt->dqio_sem);
+       return ret;
 }
 
 static int v2_write_dquot(struct dquot *dquot)
 {
-       return qtree_write_dquot(sb_dqinfo(dquot->dq_sb, dquot->dq_id.type)->dqi_priv, dquot);
+       struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
+       int ret;
+       bool alloc = false;
+
+       /*
+        * If space for dquot is already allocated, we don't need any
+        * protection as we'll only overwrite the place of dquot. We are
+        * still protected by concurrent writes of the same dquot by
+        * dquot->dq_lock.
+        */
+       if (!dquot->dq_off) {
+               alloc = true;
+               down_write(&dqopt->dqio_sem);
+       }
+       ret = qtree_write_dquot(
+                       sb_dqinfo(dquot->dq_sb, dquot->dq_id.type)->dqi_priv,
+                       dquot);
+       if (alloc)
+               up_write(&dqopt->dqio_sem);
+       return ret;
 }
 
 static int v2_release_dquot(struct dquot *dquot)
 {
-       return qtree_release_dquot(sb_dqinfo(dquot->dq_sb, dquot->dq_id.type)->dqi_priv, dquot);
+       struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
+       int ret;
+
+       down_write(&dqopt->dqio_sem);
+       ret = qtree_release_dquot(sb_dqinfo(dquot->dq_sb, dquot->dq_id.type)->dqi_priv, dquot);
+       up_write(&dqopt->dqio_sem);
+
+       return ret;
 }
 
 static int v2_free_file_info(struct super_block *sb, int type)
@@ -306,7 +355,13 @@ static int v2_free_file_info(struct super_block *sb, int type)
 
 static int v2_get_next_id(struct super_block *sb, struct kqid *qid)
 {
-       return qtree_get_next_id(sb_dqinfo(sb, qid->type)->dqi_priv, qid);
+       struct quota_info *dqopt = sb_dqopt(sb);
+       int ret;
+
+       down_read(&dqopt->dqio_sem);
+       ret = qtree_get_next_id(sb_dqinfo(sb, qid->type)->dqi_priv, qid);
+       up_read(&dqopt->dqio_sem);
+       return ret;
 }
 
 static const struct quota_format_ops v2_format_ops = {