reiserfs: locking, handle nested locks properly

The reiserfs write lock replaced the BKL and uses similar semantics.

Frederic's locking code makes a distinction between when the lock is nested
and when it's being acquired/released, but I don't think that's the right
distinction to make.

The right distinction is between the lock being released at end-of-use and
the lock being released for a schedule. The unlock should return the depth
and the lock should restore it, rather than the other way around as it is now.

This patch implements that and adds a number of places where the lock
should be dropped.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>

1 files changed, 36 insertions, 41 deletions

diff --git a/fs/reiserfs/inode.c b/fs/reiserfs/inode.c
index bf1331a0f04b..4a3a57c66820 100644
--- a/fs/reiserfs/inode.c
+++ b/fs/reiserfs/inode.c
@@ -41,11 +41,10 @@ void reiserfs_evict_inode(struct inode *inode)
 
         /* The = 0 happens when we abort creating a new inode for some reason like lack of space.. */
         if (!(inode->i_state & I_NEW) && INODE_PKEY(inode)->k_objectid != 0) {  /* also handles bad_inode case */
-                int depth;
 
                 reiserfs_delete_xattrs(inode);
 
-                depth = reiserfs_write_lock_once(inode->i_sb);
+                reiserfs_write_lock(inode->i_sb);
 
                 if (journal_begin(&th, inode->i_sb, jbegin_count))
                         goto out;
@@ -74,7 +73,7 @@ void reiserfs_evict_inode(struct inode *inode)
                 remove_save_link(inode, 0 /* not truncate */ ); /* we can't do anything
                                                                  * about an error here */
 out:
-                reiserfs_write_unlock_once(inode->i_sb, depth);
+                reiserfs_write_unlock(inode->i_sb);
         } else {
                 /* no object items are in the tree */
                 ;
@@ -611,7 +610,6 @@ int reiserfs_get_block(struct inode *inode, sector_t block,
         __le32 *item;
         int done;
         int fs_gen;
-        int lock_depth;
         struct reiserfs_transaction_handle *th = NULL;
         /* space reserved in transaction batch:
            . 3 balancings in direct->indirect conversion
@@ -627,11 +625,11 @@ int reiserfs_get_block(struct inode *inode, sector_t block,
         loff_t new_offset =
             (((loff_t) block) << inode->i_sb->s_blocksize_bits) + 1;
 
-        lock_depth = reiserfs_write_lock_once(inode->i_sb);
+        reiserfs_write_lock(inode->i_sb);
         version = get_inode_item_key_version(inode);
 
         if (!file_capable(inode, block)) {
-                reiserfs_write_unlock_once(inode->i_sb, lock_depth);
+                reiserfs_write_unlock(inode->i_sb);
                 return -EFBIG;
         }
 
@@ -643,7 +641,7 @@ int reiserfs_get_block(struct inode *inode, sector_t block,
                 /* find number of block-th logical block of the file */
                 ret = _get_block_create_0(inode, block, bh_result,
                                           create | GET_BLOCK_READ_DIRECT);
-                reiserfs_write_unlock_once(inode->i_sb, lock_depth);
+                reiserfs_write_unlock(inode->i_sb);
                 return ret;
         }
         /*
@@ -761,7 +759,7 @@ int reiserfs_get_block(struct inode *inode, sector_t block,
                 if (!dangle && th)
                         retval = reiserfs_end_persistent_transaction(th);
 
-                reiserfs_write_unlock_once(inode->i_sb, lock_depth);
+                reiserfs_write_unlock(inode->i_sb);
 
                 /* the item was found, so new blocks were not added to the file
                  ** there is no need to make sure the inode is updated with this
@@ -1012,11 +1010,7 @@ int reiserfs_get_block(struct inode *inode, sector_t block,
                  * long time.  reschedule if needed and also release the write
                  * lock for others.
                  */
-                if (need_resched()) {
-                        reiserfs_write_unlock_once(inode->i_sb, lock_depth);
-                        schedule();
-                        lock_depth = reiserfs_write_lock_once(inode->i_sb);
-                }
+                reiserfs_cond_resched(inode->i_sb);
 
                 retval = search_for_position_by_key(inode->i_sb, &key, &path);
                 if (retval == IO_ERROR) {
@@ -1051,7 +1045,7 @@ int reiserfs_get_block(struct inode *inode, sector_t block,
                         retval = err;
         }
 
-        reiserfs_write_unlock_once(inode->i_sb, lock_depth);
+        reiserfs_write_unlock(inode->i_sb);
         reiserfs_check_path(&path);
         return retval;
 }
@@ -1510,14 +1504,15 @@ struct inode *reiserfs_iget(struct super_block *s, const struct cpu_key *key)
 {
         struct inode *inode;
         struct reiserfs_iget_args args;
+        int depth;
 
         args.objectid = key->on_disk_key.k_objectid;
         args.dirid = key->on_disk_key.k_dir_id;
-        reiserfs_write_unlock(s);
+        depth = reiserfs_write_unlock_nested(s);
         inode = iget5_locked(s, key->on_disk_key.k_objectid,
                              reiserfs_find_actor, reiserfs_init_locked_inode,
                              (void *)(&args));
-        reiserfs_write_lock(s);
+        reiserfs_write_lock_nested(s, depth);
         if (!inode)
                 return ERR_PTR(-ENOMEM);
 
@@ -1781,6 +1776,7 @@ int reiserfs_new_inode(struct reiserfs_transaction_handle *th,
         struct stat_data sd;
         int retval;
         int err;
+        int depth;
 
         BUG_ON(!th->t_trans_id);
 
@@ -1813,10 +1809,10 @@ int reiserfs_new_inode(struct reiserfs_transaction_handle *th,
         memcpy(INODE_PKEY(inode), &(ih.ih_key), KEY_SIZE);
         args.dirid = le32_to_cpu(ih.ih_key.k_dir_id);
 
-        reiserfs_write_unlock(inode->i_sb);
+        depth = reiserfs_write_unlock_nested(inode->i_sb);
         err = insert_inode_locked4(inode, args.objectid,
                              reiserfs_find_actor, &args);
-        reiserfs_write_lock(inode->i_sb);
+        reiserfs_write_lock_nested(inode->i_sb, depth);
         if (err) {
                 err = -EINVAL;
                 goto out_bad_inode;
@@ -2108,9 +2104,8 @@ int reiserfs_truncate_file(struct inode *inode, int update_timestamps)
         int error;
         struct buffer_head *bh = NULL;
         int err2;
-        int lock_depth;
 
-        lock_depth = reiserfs_write_lock_once(inode->i_sb);
+        reiserfs_write_lock(inode->i_sb);
 
         if (inode->i_size > 0) {
                 error = grab_tail_page(inode, &page, &bh);
@@ -2179,7 +2174,7 @@ int reiserfs_truncate_file(struct inode *inode, int update_timestamps)
                 page_cache_release(page);
         }
 
-        reiserfs_write_unlock_once(inode->i_sb, lock_depth);
+        reiserfs_write_unlock(inode->i_sb);
 
         return 0;
       out:
@@ -2188,7 +2183,7 @@ int reiserfs_truncate_file(struct inode *inode, int update_timestamps)
                 page_cache_release(page);
         }
 
-        reiserfs_write_unlock_once(inode->i_sb, lock_depth);
+        reiserfs_write_unlock(inode->i_sb);
 
         return error;
 }
@@ -2653,10 +2648,11 @@ int __reiserfs_write_begin(struct page *page, unsigned from, unsigned len)
         struct inode *inode = page->mapping->host;
         int ret;
         int old_ref = 0;
+        int depth;
 
-        reiserfs_write_unlock(inode->i_sb);
+        depth = reiserfs_write_unlock_nested(inode->i_sb);
         reiserfs_wait_on_write_block(inode->i_sb);
-        reiserfs_write_lock(inode->i_sb);
+        reiserfs_write_lock_nested(inode->i_sb, depth);
 
         fix_tail_page_for_writing(page);
         if (reiserfs_transaction_running(inode->i_sb)) {
@@ -2713,7 +2709,6 @@ static int reiserfs_write_end(struct file *file, struct address_space *mapping,
         int update_sd = 0;
         struct reiserfs_transaction_handle *th;
         unsigned start;
-        int lock_depth = 0;
         bool locked = false;
 
         if ((unsigned long)fsdata & AOP_FLAG_CONT_EXPAND)
@@ -2742,7 +2737,7 @@ static int reiserfs_write_end(struct file *file, struct address_space *mapping,
          */
         if (pos + copied > inode->i_size) {
                 struct reiserfs_transaction_handle myth;
-                lock_depth = reiserfs_write_lock_once(inode->i_sb);
+                reiserfs_write_lock(inode->i_sb);
                 locked = true;
                 /* If the file have grown beyond the border where it
                    can have a tail, unmark it as needing a tail
@@ -2773,7 +2768,7 @@ static int reiserfs_write_end(struct file *file, struct address_space *mapping,
         }
         if (th) {
                 if (!locked) {
-                        lock_depth = reiserfs_write_lock_once(inode->i_sb);
+                        reiserfs_write_lock(inode->i_sb);
                         locked = true;
                 }
                 if (!update_sd)
@@ -2785,7 +2780,7 @@ static int reiserfs_write_end(struct file *file, struct address_space *mapping,
 
       out:
         if (locked)
-                reiserfs_write_unlock_once(inode->i_sb, lock_depth);
+                reiserfs_write_unlock(inode->i_sb);
         unlock_page(page);
         page_cache_release(page);
 
@@ -2795,7 +2790,7 @@ static int reiserfs_write_end(struct file *file, struct address_space *mapping,
         return ret == 0 ? copied : ret;
 
       journal_error:
-        reiserfs_write_unlock_once(inode->i_sb, lock_depth);
+        reiserfs_write_unlock(inode->i_sb);
         locked = false;
         if (th) {
                 if (!update_sd)
@@ -2813,10 +2808,11 @@ int reiserfs_commit_write(struct file *f, struct page *page,
         int ret = 0;
         int update_sd = 0;
         struct reiserfs_transaction_handle *th = NULL;
+        int depth;
 
-        reiserfs_write_unlock(inode->i_sb);
+        depth = reiserfs_write_unlock_nested(inode->i_sb);
         reiserfs_wait_on_write_block(inode->i_sb);
-        reiserfs_write_lock(inode->i_sb);
+        reiserfs_write_lock_nested(inode->i_sb, depth);
 
         if (reiserfs_transaction_running(inode->i_sb)) {
                 th = current->journal_info;
@@ -3115,7 +3111,6 @@ int reiserfs_setattr(struct dentry *dentry, struct iattr *attr)
 {
         struct inode *inode = dentry->d_inode;
         unsigned int ia_valid;
-        int depth;
         int error;
 
         error = inode_change_ok(inode, attr);
@@ -3127,14 +3122,14 @@ int reiserfs_setattr(struct dentry *dentry, struct iattr *attr)
 
         if (is_quota_modification(inode, attr))
                 dquot_initialize(inode);
-        depth = reiserfs_write_lock_once(inode->i_sb);
+        reiserfs_write_lock(inode->i_sb);
         if (attr->ia_valid & ATTR_SIZE) {
                 /* version 2 items will be caught by the s_maxbytes check
                  ** done for us in vmtruncate
                  */
                 if (get_inode_item_key_version(inode) == KEY_FORMAT_3_5 &&
                     attr->ia_size > MAX_NON_LFS) {
-                        reiserfs_write_unlock_once(inode->i_sb, depth);
+                        reiserfs_write_unlock(inode->i_sb);
                         error = -EFBIG;
                         goto out;
                 }
@@ -3157,7 +3152,7 @@ int reiserfs_setattr(struct dentry *dentry, struct iattr *attr)
                                         error = err;
                         }
                         if (error) {
-                                reiserfs_write_unlock_once(inode->i_sb, depth);
+                                reiserfs_write_unlock(inode->i_sb);
                                 goto out;
                         }
                         /*
@@ -3167,7 +3162,7 @@ int reiserfs_setattr(struct dentry *dentry, struct iattr *attr)
                         attr->ia_valid |= (ATTR_MTIME | ATTR_CTIME);
                 }
         }
-        reiserfs_write_unlock_once(inode->i_sb, depth);
+        reiserfs_write_unlock(inode->i_sb);
 
         if ((((attr->ia_valid & ATTR_UID) && (from_kuid(&init_user_ns, attr->ia_uid) & ~0xffff)) ||
              ((attr->ia_valid & ATTR_GID) && (from_kgid(&init_user_ns, attr->ia_gid) & ~0xffff))) &&
@@ -3192,16 +3187,16 @@ int reiserfs_setattr(struct dentry *dentry, struct iattr *attr)
                         return error;
 
                 /* (user+group)*(old+new) structure - we count quota info and , inode write (sb, inode) */
-                depth = reiserfs_write_lock_once(inode->i_sb);
+                reiserfs_write_lock(inode->i_sb);
                 error = journal_begin(&th, inode->i_sb, jbegin_count);
-                reiserfs_write_unlock_once(inode->i_sb, depth);
+                reiserfs_write_unlock(inode->i_sb);
                 if (error)
                         goto out;
                 error = dquot_transfer(inode, attr);
-                depth = reiserfs_write_lock_once(inode->i_sb);
+                reiserfs_write_lock(inode->i_sb);
                 if (error) {
                         journal_end(&th, inode->i_sb, jbegin_count);
-                        reiserfs_write_unlock_once(inode->i_sb, depth);
+                        reiserfs_write_unlock(inode->i_sb);
                         goto out;
                 }
 
@@ -3213,7 +3208,7 @@ int reiserfs_setattr(struct dentry *dentry, struct iattr *attr)
                         inode->i_gid = attr->ia_gid;
                 mark_inode_dirty(inode);
                 error = journal_end(&th, inode->i_sb, jbegin_count);
-                reiserfs_write_unlock_once(inode->i_sb, depth);
+                reiserfs_write_unlock(inode->i_sb);
                 if (error)
                         goto out;
         }