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reiserfs: locking, handle nested locks properly

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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>
This commit is contained in:
Jeff Mahoney
2013-08-08 17:34:46 -04:00
committed by Jeff Mahoney
parent 4c05141df5
commit 278f6679f4
13 changed files with 204 additions and 197 deletions
Download Patch File Download Diff File Expand all files Collapse all files
fs/reiserfs/namei.c
+8 -16
View File
@@ -325,7 +325,6 @@ static struct dentry *reiserfs_lookup(struct inode *dir, struct dentry *dentry,
unsigned int flags)
{
int retval;
int lock_depth;
struct inode *inode = NULL;
struct reiserfs_dir_entry de;
INITIALIZE_PATH(path_to_entry);
@@ -333,12 +332,7 @@ static struct dentry *reiserfs_lookup(struct inode *dir, struct dentry *dentry,
if (REISERFS_MAX_NAME(dir->i_sb->s_blocksize) < dentry->d_name.len)
return ERR_PTR(-ENAMETOOLONG);
/*
* Might be called with or without the write lock, must be careful
* to not recursively hold it in case we want to release the lock
* before rescheduling.
*/
lock_depth = reiserfs_write_lock_once(dir->i_sb);
reiserfs_write_lock(dir->i_sb);
de.de_gen_number_bit_string = NULL;
retval =
@@ -349,7 +343,7 @@ static struct dentry *reiserfs_lookup(struct inode *dir, struct dentry *dentry,
inode = reiserfs_iget(dir->i_sb,
(struct cpu_key *)&(de.de_dir_id));
if (!inode || IS_ERR(inode)) {
reiserfs_write_unlock_once(dir->i_sb, lock_depth);
reiserfs_write_unlock(dir->i_sb);
return ERR_PTR(-EACCES);
}
@@ -358,7 +352,7 @@ static struct dentry *reiserfs_lookup(struct inode *dir, struct dentry *dentry,
if (IS_PRIVATE(dir))
inode->i_flags |= S_PRIVATE;
}
reiserfs_write_unlock_once(dir->i_sb, lock_depth);
reiserfs_write_unlock(dir->i_sb);
if (retval == IO_ERROR) {
return ERR_PTR(-EIO);
}
@@ -727,7 +721,6 @@ static int reiserfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode
struct inode *inode;
struct reiserfs_transaction_handle th;
struct reiserfs_security_handle security;
int lock_depth;
/* We need blocks for transaction + (user+group)*(quotas for new inode + update of quota for directory owner) */
int jbegin_count =
JOURNAL_PER_BALANCE_CNT * 3 +
@@ -753,7 +746,7 @@ static int reiserfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode
return retval;
}
jbegin_count += retval;
lock_depth = reiserfs_write_lock_once(dir->i_sb);
reiserfs_write_lock(dir->i_sb);
retval = journal_begin(&th, dir->i_sb, jbegin_count);
if (retval) {
@@ -804,7 +797,7 @@ static int reiserfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode
d_instantiate(dentry, inode);
retval = journal_end(&th, dir->i_sb, jbegin_count);
out_failed:
reiserfs_write_unlock_once(dir->i_sb, lock_depth);
reiserfs_write_unlock(dir->i_sb);
return retval;
}
@@ -920,7 +913,6 @@ static int reiserfs_unlink(struct inode *dir, struct dentry *dentry)
struct reiserfs_transaction_handle th;
int jbegin_count;
unsigned long savelink;
int depth;
dquot_initialize(dir);
@@ -934,7 +926,7 @@ static int reiserfs_unlink(struct inode *dir, struct dentry *dentry)
JOURNAL_PER_BALANCE_CNT * 2 + 2 +
4 * REISERFS_QUOTA_TRANS_BLOCKS(dir->i_sb);
depth = reiserfs_write_lock_once(dir->i_sb);
reiserfs_write_lock(dir->i_sb);
retval = journal_begin(&th, dir->i_sb, jbegin_count);
if (retval)
goto out_unlink;
@@ -995,7 +987,7 @@ static int reiserfs_unlink(struct inode *dir, struct dentry *dentry)
retval = journal_end(&th, dir->i_sb, jbegin_count);
reiserfs_check_path(&path);
reiserfs_write_unlock_once(dir->i_sb, depth);
reiserfs_write_unlock(dir->i_sb);
return retval;
end_unlink:
@@ -1005,7 +997,7 @@ static int reiserfs_unlink(struct inode *dir, struct dentry *dentry)
if (err)
retval = err;
out_unlink:
reiserfs_write_unlock_once(dir->i_sb, depth);
reiserfs_write_unlock(dir->i_sb);
return retval;
}