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>
diff --git a/fs/reiserfs/inode.c b/fs/reiserfs/inode.c
index bf1331a..4a3a57c 100644
--- a/fs/reiserfs/inode.c
+++ b/fs/reiserfs/inode.c
@@ -41,11 +41,10 @@
/* 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 @@
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 @@
__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 @@
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 @@
/* 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 @@
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 @@
* 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 @@
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 *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 @@
struct stat_data sd;
int retval;
int err;
+ int depth;
BUG_ON(!th->t_trans_id);
@@ -1813,10 +1809,10 @@
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 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 @@
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 @@
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 @@
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 @@
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 @@
*/
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 @@
}
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 @@
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 @@
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 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 @@
{
struct inode *inode = dentry->d_inode;
unsigned int ia_valid;
- int depth;
int error;
error = inode_change_ok(inode, attr);
@@ -3127,14 +3122,14 @@
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 @@
error = err;
}
if (error) {
- reiserfs_write_unlock_once(inode->i_sb, depth);
+ reiserfs_write_unlock(inode->i_sb);
goto out;
}
/*
@@ -3167,7 +3162,7 @@
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 @@
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 @@
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;
}