BKL: Remove BKL from isofs
As in other file systems, we can replace the big kernel lock
with a private mutex in isofs. This means we can now access
multiple file systems concurrently, but it also means that
we serialize readdir and lookup across sleeping operations
which previously released the big kernel lock. This should
not matter though, as these operations are in practice
serialized through the hardware access.
The isofs_get_blocks functions now does not take any lock
any more, it used to recursively get the BKL. After looking
at the code for hours, I convinced myself that it was never
needed here anyway, because it only reads constant fields
of the inode and writes to a buffer head array that is
at this time only visible to the caller.
The get_sb and fill_super operations do not need the locking
at all because they operate on a file system that is either
about to be created or to be destroyed but in either case
is not visible to other threads.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
diff --git a/fs/isofs/dir.c b/fs/isofs/dir.c
index e0aca9a..0542b6e 100644
--- a/fs/isofs/dir.c
+++ b/fs/isofs/dir.c
@@ -10,7 +10,6 @@
*
* isofs directory handling functions
*/
-#include <linux/smp_lock.h>
#include <linux/gfp.h>
#include "isofs.h"
@@ -255,18 +254,19 @@
char *tmpname;
struct iso_directory_record *tmpde;
struct inode *inode = filp->f_path.dentry->d_inode;
+ struct isofs_sb_info *sbi = ISOFS_SB(inode->i_sb);
tmpname = (char *)__get_free_page(GFP_KERNEL);
if (tmpname == NULL)
return -ENOMEM;
- lock_kernel();
+ mutex_lock(&sbi->s_mutex);
tmpde = (struct iso_directory_record *) (tmpname+1024);
result = do_isofs_readdir(inode, filp, dirent, filldir, tmpname, tmpde);
free_page((unsigned long) tmpname);
- unlock_kernel();
+ mutex_unlock(&sbi->s_mutex);
return result;
}
diff --git a/fs/isofs/inode.c b/fs/isofs/inode.c
index 05baf772..09ff41a 100644
--- a/fs/isofs/inode.c
+++ b/fs/isofs/inode.c
@@ -17,7 +17,6 @@
#include <linux/slab.h>
#include <linux/nls.h>
#include <linux/ctype.h>
-#include <linux/smp_lock.h>
#include <linux/statfs.h>
#include <linux/cdrom.h>
#include <linux/parser.h>
@@ -44,11 +43,7 @@
struct isofs_sb_info *sbi = ISOFS_SB(sb);
#ifdef CONFIG_JOLIET
- lock_kernel();
-
unload_nls(sbi->s_nls_iocharset);
-
- unlock_kernel();
#endif
kfree(sbi);
@@ -571,15 +566,11 @@
int table, error = -EINVAL;
unsigned int vol_desc_start;
- lock_kernel();
-
save_mount_options(s, data);
sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
- if (!sbi) {
- unlock_kernel();
+ if (!sbi)
return -ENOMEM;
- }
s->s_fs_info = sbi;
if (!parse_options((char *)data, &opt))
@@ -827,6 +818,7 @@
sbi->s_utf8 = opt.utf8;
sbi->s_nocompress = opt.nocompress;
sbi->s_overriderockperm = opt.overriderockperm;
+ mutex_init(&sbi->s_mutex);
/*
* It would be incredibly stupid to allow people to mark every file
* on the disk as suid, so we merely allow them to set the default
@@ -904,7 +896,6 @@
kfree(opt.iocharset);
- unlock_kernel();
return 0;
/*
@@ -944,7 +935,6 @@
kfree(opt.iocharset);
kfree(sbi);
s->s_fs_info = NULL;
- unlock_kernel();
return error;
}
@@ -983,8 +973,6 @@
int section, rv, error;
struct iso_inode_info *ei = ISOFS_I(inode);
- lock_kernel();
-
error = -EIO;
rv = 0;
if (iblock < 0 || iblock != iblock_s) {
@@ -1060,7 +1048,6 @@
error = 0;
abort:
- unlock_kernel();
return rv != 0 ? rv : error;
}
diff --git a/fs/isofs/isofs.h b/fs/isofs/isofs.h
index 7d33de8..2882dc0 100644
--- a/fs/isofs/isofs.h
+++ b/fs/isofs/isofs.h
@@ -55,6 +55,7 @@
gid_t s_gid;
uid_t s_uid;
struct nls_table *s_nls_iocharset; /* Native language support table */
+ struct mutex s_mutex; /* replaces BKL, please remove if possible */
};
#define ISOFS_INVALID_MODE ((mode_t) -1)
diff --git a/fs/isofs/namei.c b/fs/isofs/namei.c
index ab438be..0d23abf 100644
--- a/fs/isofs/namei.c
+++ b/fs/isofs/namei.c
@@ -6,7 +6,6 @@
* (C) 1991 Linus Torvalds - minix filesystem
*/
-#include <linux/smp_lock.h>
#include <linux/gfp.h>
#include "isofs.h"
@@ -168,6 +167,7 @@
int found;
unsigned long uninitialized_var(block);
unsigned long uninitialized_var(offset);
+ struct isofs_sb_info *sbi = ISOFS_SB(dir->i_sb);
struct inode *inode;
struct page *page;
@@ -177,7 +177,7 @@
if (!page)
return ERR_PTR(-ENOMEM);
- lock_kernel();
+ mutex_lock(&sbi->s_mutex);
found = isofs_find_entry(dir, dentry,
&block, &offset,
page_address(page),
@@ -188,10 +188,10 @@
if (found) {
inode = isofs_iget(dir->i_sb, block, offset);
if (IS_ERR(inode)) {
- unlock_kernel();
+ mutex_unlock(&sbi->s_mutex);
return ERR_CAST(inode);
}
}
- unlock_kernel();
+ mutex_unlock(&sbi->s_mutex);
return d_splice_alias(inode, dentry);
}
diff --git a/fs/isofs/rock.c b/fs/isofs/rock.c
index 96a685c..f9cd04d 100644
--- a/fs/isofs/rock.c
+++ b/fs/isofs/rock.c
@@ -8,7 +8,6 @@
#include <linux/slab.h>
#include <linux/pagemap.h>
-#include <linux/smp_lock.h>
#include "isofs.h"
#include "rock.h"
@@ -661,6 +660,7 @@
{
struct inode *inode = page->mapping->host;
struct iso_inode_info *ei = ISOFS_I(inode);
+ struct isofs_sb_info *sbi = ISOFS_SB(inode->i_sb);
char *link = kmap(page);
unsigned long bufsize = ISOFS_BUFFER_SIZE(inode);
struct buffer_head *bh;
@@ -673,12 +673,12 @@
struct rock_state rs;
int ret;
- if (!ISOFS_SB(inode->i_sb)->s_rock)
+ if (!sbi->s_rock)
goto error;
init_rock_state(&rs, inode);
block = ei->i_iget5_block;
- lock_kernel();
+ mutex_lock(&sbi->s_mutex);
bh = sb_bread(inode->i_sb, block);
if (!bh)
goto out_noread;
@@ -748,7 +748,7 @@
goto fail;
brelse(bh);
*rpnt = '\0';
- unlock_kernel();
+ mutex_unlock(&sbi->s_mutex);
SetPageUptodate(page);
kunmap(page);
unlock_page(page);
@@ -765,7 +765,7 @@
printk("symlink spans iso9660 blocks\n");
fail:
brelse(bh);
- unlock_kernel();
+ mutex_unlock(&sbi->s_mutex);
error:
SetPageError(page);
kunmap(page);