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bfs: kill BKL
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Replace the BKL-based locking scheme used in the bfs driver by a private
filesystem-wide mutex.

Signed-off-by: Dmitri Vorobiev <[email protected]>
Cc: Tigran Aivazian <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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@torvalds
Dmitri Vorobiev authored and torvalds committed Jul 26, 2008
1 parent 75b25b4 commit 3f165e4
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Showing 4 changed files with 44 additions and 31 deletions.
1 change: 1 addition & 0 deletions fs/bfs/bfs.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -18,6 +18,7 @@ struct bfs_sb_info {
unsigned long si_lasti;
unsigned long *si_imap;
struct buffer_head *si_sbh; /* buffer header w/superblock */
struct mutex bfs_lock;
};

/*
Expand Down
46 changes: 26 additions & 20 deletions fs/bfs/dir.c
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Original file line number Diff line number Diff line change
Expand Up @@ -32,16 +32,17 @@ static int bfs_readdir(struct file *f, void *dirent, filldir_t filldir)
struct inode *dir = f->f_path.dentry->d_inode;
struct buffer_head *bh;
struct bfs_dirent *de;
struct bfs_sb_info *info = BFS_SB(dir->i_sb);
unsigned int offset;
int block;

lock_kernel();
mutex_lock(&info->bfs_lock);

if (f->f_pos & (BFS_DIRENT_SIZE - 1)) {
printf("Bad f_pos=%08lx for %s:%08lx\n",
(unsigned long)f->f_pos,
dir->i_sb->s_id, dir->i_ino);
unlock_kernel();
mutex_unlock(&info->bfs_lock);
return -EBADF;
}

Expand All @@ -61,7 +62,7 @@ static int bfs_readdir(struct file *f, void *dirent, filldir_t filldir)
le16_to_cpu(de->ino),
DT_UNKNOWN) < 0) {
brelse(bh);
unlock_kernel();
mutex_unlock(&info->bfs_lock);
return 0;
}
}
Expand All @@ -71,7 +72,7 @@ static int bfs_readdir(struct file *f, void *dirent, filldir_t filldir)
brelse(bh);
}

unlock_kernel();
mutex_unlock(&info->bfs_lock);
return 0;
}

Expand All @@ -95,10 +96,10 @@ static int bfs_create(struct inode *dir, struct dentry *dentry, int mode,
inode = new_inode(s);
if (!inode)
return -ENOSPC;
lock_kernel();
mutex_lock(&info->bfs_lock);
ino = find_first_zero_bit(info->si_imap, info->si_lasti);
if (ino > info->si_lasti) {
unlock_kernel();
mutex_unlock(&info->bfs_lock);
iput(inode);
return -ENOSPC;
}
Expand All @@ -125,10 +126,10 @@ static int bfs_create(struct inode *dir, struct dentry *dentry, int mode,
if (err) {
inode_dec_link_count(inode);
iput(inode);
unlock_kernel();
mutex_unlock(&info->bfs_lock);
return err;
}
unlock_kernel();
mutex_unlock(&info->bfs_lock);
d_instantiate(dentry, inode);
return 0;
}
Expand All @@ -139,22 +140,23 @@ static struct dentry *bfs_lookup(struct inode *dir, struct dentry *dentry,
struct inode *inode = NULL;
struct buffer_head *bh;
struct bfs_dirent *de;
struct bfs_sb_info *info = BFS_SB(dir->i_sb);

if (dentry->d_name.len > BFS_NAMELEN)
return ERR_PTR(-ENAMETOOLONG);

lock_kernel();
mutex_lock(&info->bfs_lock);
bh = bfs_find_entry(dir, dentry->d_name.name, dentry->d_name.len, &de);
if (bh) {
unsigned long ino = (unsigned long)le16_to_cpu(de->ino);
brelse(bh);
inode = bfs_iget(dir->i_sb, ino);
if (IS_ERR(inode)) {
unlock_kernel();
mutex_unlock(&info->bfs_lock);
return ERR_CAST(inode);
}
}
unlock_kernel();
mutex_unlock(&info->bfs_lock);
d_add(dentry, inode);
return NULL;
}
Expand All @@ -163,33 +165,34 @@ static int bfs_link(struct dentry *old, struct inode *dir,
struct dentry *new)
{
struct inode *inode = old->d_inode;
struct bfs_sb_info *info = BFS_SB(inode->i_sb);
int err;

lock_kernel();
mutex_lock(&info->bfs_lock);
err = bfs_add_entry(dir, new->d_name.name, new->d_name.len,
inode->i_ino);
if (err) {
unlock_kernel();
mutex_unlock(&info->bfs_lock);
return err;
}
inc_nlink(inode);
inode->i_ctime = CURRENT_TIME_SEC;
mark_inode_dirty(inode);
atomic_inc(&inode->i_count);
d_instantiate(new, inode);
unlock_kernel();
mutex_unlock(&info->bfs_lock);
return 0;
}

static int bfs_unlink(struct inode *dir, struct dentry *dentry)
{
int error = -ENOENT;
struct inode *inode;
struct inode *inode = dentry->d_inode;
struct buffer_head *bh;
struct bfs_dirent *de;
struct bfs_sb_info *info = BFS_SB(inode->i_sb);

inode = dentry->d_inode;
lock_kernel();
mutex_lock(&info->bfs_lock);
bh = bfs_find_entry(dir, dentry->d_name.name, dentry->d_name.len, &de);
if (!bh || (le16_to_cpu(de->ino) != inode->i_ino))
goto out_brelse;
Expand All @@ -210,7 +213,7 @@ static int bfs_unlink(struct inode *dir, struct dentry *dentry)

out_brelse:
brelse(bh);
unlock_kernel();
mutex_unlock(&info->bfs_lock);
return error;
}

Expand All @@ -220,14 +223,17 @@ static int bfs_rename(struct inode *old_dir, struct dentry *old_dentry,
struct inode *old_inode, *new_inode;
struct buffer_head *old_bh, *new_bh;
struct bfs_dirent *old_de, *new_de;
struct bfs_sb_info *info;
int error = -ENOENT;

old_bh = new_bh = NULL;
old_inode = old_dentry->d_inode;
if (S_ISDIR(old_inode->i_mode))
return -EINVAL;

lock_kernel();
info = BFS_SB(old_inode->i_sb);

mutex_lock(&info->bfs_lock);
old_bh = bfs_find_entry(old_dir,
old_dentry->d_name.name,
old_dentry->d_name.len, &old_de);
Expand Down Expand Up @@ -264,7 +270,7 @@ static int bfs_rename(struct inode *old_dir, struct dentry *old_dentry,
error = 0;

end_rename:
unlock_kernel();
mutex_unlock(&info->bfs_lock);
brelse(old_bh);
brelse(new_bh);
return error;
Expand Down
4 changes: 2 additions & 2 deletions fs/bfs/file.c
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Original file line number Diff line number Diff line change
Expand Up @@ -99,7 +99,7 @@ static int bfs_get_block(struct inode *inode, sector_t block,
return -ENOSPC;

/* The rest has to be protected against itself. */
lock_kernel();
mutex_lock(&info->bfs_lock);

/*
* If the last data block for this file is the last allocated
Expand Down Expand Up @@ -151,7 +151,7 @@ static int bfs_get_block(struct inode *inode, sector_t block,
mark_buffer_dirty(sbh);
map_bh(bh_result, sb, phys);
out:
unlock_kernel();
mutex_unlock(&info->bfs_lock);
return err;
}

Expand Down
24 changes: 15 additions & 9 deletions fs/bfs/inode.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -104,6 +104,7 @@ static int bfs_write_inode(struct inode *inode, int unused)
struct bfs_inode *di;
struct buffer_head *bh;
int block, off;
struct bfs_sb_info *info = BFS_SB(inode->i_sb);

dprintf("ino=%08x\n", ino);

Expand All @@ -112,13 +113,13 @@ static int bfs_write_inode(struct inode *inode, int unused)
return -EIO;
}

lock_kernel();
mutex_lock(&info->bfs_lock);
block = (ino - BFS_ROOT_INO) / BFS_INODES_PER_BLOCK + 1;
bh = sb_bread(inode->i_sb, block);
if (!bh) {
printf("Unable to read inode %s:%08x\n",
inode->i_sb->s_id, ino);
unlock_kernel();
mutex_unlock(&info->bfs_lock);
return -EIO;
}

Expand All @@ -145,7 +146,7 @@ static int bfs_write_inode(struct inode *inode, int unused)

mark_buffer_dirty(bh);
brelse(bh);
unlock_kernel();
mutex_unlock(&info->bfs_lock);
return 0;
}

Expand All @@ -170,15 +171,15 @@ static void bfs_delete_inode(struct inode *inode)

inode->i_size = 0;
inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC;
lock_kernel();
mutex_lock(&info->bfs_lock);
mark_inode_dirty(inode);

block = (ino - BFS_ROOT_INO) / BFS_INODES_PER_BLOCK + 1;
bh = sb_bread(s, block);
if (!bh) {
printf("Unable to read inode %s:%08lx\n",
inode->i_sb->s_id, ino);
unlock_kernel();
mutex_unlock(&info->bfs_lock);
return;
}
off = (ino - BFS_ROOT_INO) % BFS_INODES_PER_BLOCK;
Expand All @@ -204,14 +205,16 @@ static void bfs_delete_inode(struct inode *inode)
info->si_lf_eblk = bi->i_sblock - 1;
mark_buffer_dirty(info->si_sbh);
}
unlock_kernel();
mutex_unlock(&info->bfs_lock);
clear_inode(inode);
}

static void bfs_put_super(struct super_block *s)
{
struct bfs_sb_info *info = BFS_SB(s);

brelse(info->si_sbh);
mutex_destroy(&info->bfs_lock);
kfree(info->si_imap);
kfree(info);
s->s_fs_info = NULL;
Expand All @@ -236,11 +239,13 @@ static int bfs_statfs(struct dentry *dentry, struct kstatfs *buf)

static void bfs_write_super(struct super_block *s)
{
lock_kernel();
struct bfs_sb_info *info = BFS_SB(s);

mutex_lock(&info->bfs_lock);
if (!(s->s_flags & MS_RDONLY))
mark_buffer_dirty(BFS_SB(s)->si_sbh);
mark_buffer_dirty(info->si_sbh);
s->s_dirt = 0;
unlock_kernel();
mutex_unlock(&info->bfs_lock);
}

static struct kmem_cache *bfs_inode_cachep;
Expand Down Expand Up @@ -409,6 +414,7 @@ static int bfs_fill_super(struct super_block *s, void *data, int silent)
s->s_dirt = 1;
}
dump_imap("read_super", s);
mutex_init(&info->bfs_lock);
return 0;

out:
Expand Down

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