Revision 38d78e587d4960d0db94add518d27ee74bad2301 authored by Vladimir Davydov on 22 March 2013, 22:04:51 UTC, committed by Linus Torvalds on 22 March 2013, 23:41:21 UTC
mnt_drop_write() must be called only if mnt_want_write() succeeded, otherwise the mnt_writers counter will diverge. mnt_writers counters are used to check if remounting FS as read-only is OK, so after an extra mnt_drop_write() call, it would be impossible to remount mqueue FS as read-only. Besides, on umount a warning would be printed like this one: ===================================== [ BUG: bad unlock balance detected! ] 3.9.0-rc3 #5 Not tainted ------------------------------------- a.out/12486 is trying to release lock (sb_writers) at: mnt_drop_write+0x1f/0x30 but there are no more locks to release! Signed-off-by: Vladimir Davydov <vdavydov@parallels.com> Cc: Doug Ledford <dledford@redhat.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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super.c
/*
* super.c
*
* Copyright (C) 2001-2002 Will Dyson <will_dyson@pobox.com>
*
* Licensed under the GNU GPL. See the file COPYING for details.
*
*/
#include <linux/fs.h>
#include <asm/page.h> /* for PAGE_SIZE */
#include "befs.h"
#include "super.h"
/**
* load_befs_sb -- Read from disk and properly byteswap all the fields
* of the befs superblock
*
*
*
*
*/
int
befs_load_sb(struct super_block *sb, befs_super_block * disk_sb)
{
befs_sb_info *befs_sb = BEFS_SB(sb);
/* Check the byte order of the filesystem */
if (disk_sb->fs_byte_order == BEFS_BYTEORDER_NATIVE_LE)
befs_sb->byte_order = BEFS_BYTESEX_LE;
else if (disk_sb->fs_byte_order == BEFS_BYTEORDER_NATIVE_BE)
befs_sb->byte_order = BEFS_BYTESEX_BE;
befs_sb->magic1 = fs32_to_cpu(sb, disk_sb->magic1);
befs_sb->magic2 = fs32_to_cpu(sb, disk_sb->magic2);
befs_sb->magic3 = fs32_to_cpu(sb, disk_sb->magic3);
befs_sb->block_size = fs32_to_cpu(sb, disk_sb->block_size);
befs_sb->block_shift = fs32_to_cpu(sb, disk_sb->block_shift);
befs_sb->num_blocks = fs64_to_cpu(sb, disk_sb->num_blocks);
befs_sb->used_blocks = fs64_to_cpu(sb, disk_sb->used_blocks);
befs_sb->inode_size = fs32_to_cpu(sb, disk_sb->inode_size);
befs_sb->blocks_per_ag = fs32_to_cpu(sb, disk_sb->blocks_per_ag);
befs_sb->ag_shift = fs32_to_cpu(sb, disk_sb->ag_shift);
befs_sb->num_ags = fs32_to_cpu(sb, disk_sb->num_ags);
befs_sb->log_blocks = fsrun_to_cpu(sb, disk_sb->log_blocks);
befs_sb->log_start = fs64_to_cpu(sb, disk_sb->log_start);
befs_sb->log_end = fs64_to_cpu(sb, disk_sb->log_end);
befs_sb->root_dir = fsrun_to_cpu(sb, disk_sb->root_dir);
befs_sb->indices = fsrun_to_cpu(sb, disk_sb->indices);
befs_sb->nls = NULL;
return BEFS_OK;
}
int
befs_check_sb(struct super_block *sb)
{
befs_sb_info *befs_sb = BEFS_SB(sb);
/* Check magic headers of super block */
if ((befs_sb->magic1 != BEFS_SUPER_MAGIC1)
|| (befs_sb->magic2 != BEFS_SUPER_MAGIC2)
|| (befs_sb->magic3 != BEFS_SUPER_MAGIC3)) {
befs_error(sb, "invalid magic header");
return BEFS_ERR;
}
/*
* Check blocksize of BEFS.
*
* Blocksize of BEFS is 1024, 2048, 4096 or 8192.
*/
if ((befs_sb->block_size != 1024)
&& (befs_sb->block_size != 2048)
&& (befs_sb->block_size != 4096)
&& (befs_sb->block_size != 8192)) {
befs_error(sb, "invalid blocksize: %u", befs_sb->block_size);
return BEFS_ERR;
}
if (befs_sb->block_size > PAGE_SIZE) {
befs_error(sb, "blocksize(%u) cannot be larger"
"than system pagesize(%lu)", befs_sb->block_size,
PAGE_SIZE);
return BEFS_ERR;
}
/*
* block_shift and block_size encode the same information
* in different ways as a consistency check.
*/
if ((1 << befs_sb->block_shift) != befs_sb->block_size) {
befs_error(sb, "block_shift disagrees with block_size. "
"Corruption likely.");
return BEFS_ERR;
}
if (befs_sb->log_start != befs_sb->log_end) {
befs_error(sb, "Filesystem not clean! There are blocks in the "
"journal. You must boot into BeOS and mount this volume "
"to make it clean.");
return BEFS_ERR;
}
return BEFS_OK;
}
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