From db71922217a214e5c9268448e537b54fc1f301ea Mon Sep 17 00:00:00 2001 From: Jan Blunck Date: Sun, 15 Aug 2010 22:51:10 +0200 Subject: 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 Signed-off-by: Arnd Bergmann Cc: Matthew Wilcox Cc: Christoph Hellwig --- fs/fat/namei_msdos.c | 7 ++++++- fs/fat/namei_vfat.c | 7 ++++++- 2 files changed, 12 insertions(+), 2 deletions(-) (limited to 'fs/fat') diff --git a/fs/fat/namei_msdos.c b/fs/fat/namei_msdos.c index bbc94ae4fd77..e2b0b978340d 100644 --- a/fs/fat/namei_msdos.c +++ b/fs/fat/namei_msdos.c @@ -9,6 +9,7 @@ #include #include #include +#include /* For lock_kernel() */ #include "fat.h" /* Characters that are undesirable in an MS-DOS file name */ @@ -662,12 +663,16 @@ static int msdos_fill_super(struct super_block *sb, void *data, int silent) { int res; + lock_kernel(); res = fat_fill_super(sb, data, silent, &msdos_dir_inode_operations, 0); - if (res) + if (res) { + unlock_kernel(); return res; + } sb->s_flags |= MS_NOATIME; sb->s_root->d_op = &msdos_dentry_operations; + unlock_kernel(); return 0; } diff --git a/fs/fat/namei_vfat.c b/fs/fat/namei_vfat.c index 6fcc7e71fbaa..9006ad9c7b11 100644 --- a/fs/fat/namei_vfat.c +++ b/fs/fat/namei_vfat.c @@ -21,6 +21,7 @@ #include #include #include +#include /* For lock_kernel() */ #include "fat.h" /* @@ -1055,15 +1056,19 @@ static int vfat_fill_super(struct super_block *sb, void *data, int silent) { int res; + lock_kernel(); res = fat_fill_super(sb, data, silent, &vfat_dir_inode_operations, 1); - if (res) + if (res) { + unlock_kernel(); return res; + } if (MSDOS_SB(sb)->options.name_check != 's') sb->s_root->d_op = &vfat_ci_dentry_ops; else sb->s_root->d_op = &vfat_dentry_ops; + unlock_kernel(); return 0; } -- cgit v1.2.2