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authorJan Blunck <jblunck@infradead.org>2010-08-15 22:51:10 +0200
committerArnd Bergmann <arnd@arndb.de>2010-10-04 21:10:10 +0200
commitdb71922217a214e5c9268448e537b54fc1f301ea (patch)
tree9c9afbf29411547891f6968e5ade29ce59d66c07 /fs/squashfs/super.c
parent899611ee7d373e5eeda08e9a8632684e1ebbbf00 (diff)
BKL: Explicitly add BKL around get_sb/fill_super
This patch is a preparation necessary to remove the BKL from do_new_mount(). It explicitly adds calls to lock_kernel()/unlock_kernel() around get_sb/fill_super operations for filesystems that still uses the BKL. I've read through all the code formerly covered by the BKL inside do_kern_mount() and have satisfied myself that it doesn't need the BKL any more. do_kern_mount() is already called without the BKL when mounting the rootfs and in nfsctl. do_kern_mount() calls vfs_kern_mount(), which is called from various places without BKL: simple_pin_fs(), nfs_do_clone_mount() through nfs_follow_mountpoint(), afs_mntpt_do_automount() through afs_mntpt_follow_link(). Both later functions are actually the filesystems follow_link inode operation. vfs_kern_mount() is calling the specified get_sb function and lets the filesystem do its job by calling the given fill_super function. Therefore I think it is safe to push down the BKL from the VFS to the low-level filesystems get_sb/fill_super operation. [arnd: do not add the BKL to those file systems that already don't use it elsewhere] Signed-off-by: Jan Blunck <jblunck@infradead.org> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Cc: Matthew Wilcox <matthew@wil.cx> Cc: Christoph Hellwig <hch@infradead.org>
Diffstat (limited to 'fs/squashfs/super.c')
-rw-r--r--fs/squashfs/super.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/fs/squashfs/super.c b/fs/squashfs/super.c
index 88b4f860665..ab1a401a0e1 100644
--- a/fs/squashfs/super.c
+++ b/fs/squashfs/super.c
@@ -87,11 +87,14 @@ static int squashfs_fill_super(struct super_block *sb, void *data, int silent)
u64 lookup_table_start, xattr_id_table_start;
int err;
+ lock_kernel();
+
TRACE("Entered squashfs_fill_superblock\n");
sb->s_fs_info = kzalloc(sizeof(*msblk), GFP_KERNEL);
if (sb->s_fs_info == NULL) {
ERROR("Failed to allocate squashfs_sb_info\n");
+ unlock_kernel();
return -ENOMEM;
}
msblk = sb->s_fs_info;
@@ -301,6 +304,7 @@ allocate_root:
TRACE("Leaving squashfs_fill_super\n");
kfree(sblk);
+ unlock_kernel();
return 0;
failed_mount:
@@ -315,11 +319,13 @@ failed_mount:
kfree(sb->s_fs_info);
sb->s_fs_info = NULL;
kfree(sblk);
+ unlock_kernel();
return err;
failure:
kfree(sb->s_fs_info);
sb->s_fs_info = NULL;
+ unlock_kernel();
return -ENOMEM;
}