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Push lock_super() into the ->remount_fs() of filesystems that care ab…
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…out it

Note that since we can't run into contention between remount_fs and write_super
(due to exclusion on s_umount), we have to care only about filesystems that
touch lock_super() on their own.  Out of those ext3, ext4, hpfs, sysv and ufs
do need it; fat doesn't since its ->remount_fs() only accesses assign-once
data (basically, it's "we have no atime on directories and only have atime on
files for vfat; force nodiratime and possibly noatime into *flags").

[folded a build fix from hch]

Signed-off-by: Al Viro <[email protected]>
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Al Viro committed Jun 12, 2009
1 parent 6cfd014 commit bbd6851
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Showing 6 changed files with 21 additions and 3 deletions.
3 changes: 3 additions & 0 deletions fs/ext3/super.c
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Original file line number Diff line number Diff line change
Expand Up @@ -2491,6 +2491,7 @@ static int ext3_remount (struct super_block * sb, int * flags, char * data)
#endif

/* Store the original options */
lock_super(sb);
old_sb_flags = sb->s_flags;
old_opts.s_mount_opt = sbi->s_mount_opt;
old_opts.s_resuid = sbi->s_resuid;
Expand Down Expand Up @@ -2598,6 +2599,7 @@ static int ext3_remount (struct super_block * sb, int * flags, char * data)
old_opts.s_qf_names[i] != sbi->s_qf_names[i])
kfree(old_opts.s_qf_names[i]);
#endif
unlock_super(sb);
return 0;
restore_opts:
sb->s_flags = old_sb_flags;
Expand All @@ -2614,6 +2616,7 @@ static int ext3_remount (struct super_block * sb, int * flags, char * data)
sbi->s_qf_names[i] = old_opts.s_qf_names[i];
}
#endif
unlock_super(sb);
return err;
}

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3 changes: 3 additions & 0 deletions fs/ext4/super.c
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Original file line number Diff line number Diff line change
Expand Up @@ -3421,6 +3421,7 @@ static int ext4_remount(struct super_block *sb, int *flags, char *data)
#endif

/* Store the original options */
lock_super(sb);
old_sb_flags = sb->s_flags;
old_opts.s_mount_opt = sbi->s_mount_opt;
old_opts.s_resuid = sbi->s_resuid;
Expand Down Expand Up @@ -3554,6 +3555,7 @@ static int ext4_remount(struct super_block *sb, int *flags, char *data)
old_opts.s_qf_names[i] != sbi->s_qf_names[i])
kfree(old_opts.s_qf_names[i]);
#endif
unlock_super(sb);
return 0;

restore_opts:
Expand All @@ -3573,6 +3575,7 @@ static int ext4_remount(struct super_block *sb, int *flags, char *data)
sbi->s_qf_names[i] = old_opts.s_qf_names[i];
}
#endif
unlock_super(sb);
return err;
}

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3 changes: 3 additions & 0 deletions fs/hpfs/super.c
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Original file line number Diff line number Diff line change
Expand Up @@ -398,6 +398,7 @@ static int hpfs_remount_fs(struct super_block *s, int *flags, char *data)

*flags |= MS_NOATIME;

lock_super(s);
uid = sbi->sb_uid; gid = sbi->sb_gid;
umask = 0777 & ~sbi->sb_mode;
lowercase = sbi->sb_lowercase; conv = sbi->sb_conv;
Expand Down Expand Up @@ -430,9 +431,11 @@ static int hpfs_remount_fs(struct super_block *s, int *flags, char *data)

replace_mount_options(s, new_opts);

unlock_super(s);
return 0;

out_err:
unlock_super(s);
kfree(new_opts);
return -EINVAL;
}
Expand Down
2 changes: 0 additions & 2 deletions fs/super.c
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Original file line number Diff line number Diff line change
Expand Up @@ -556,9 +556,7 @@ int do_remount_sb(struct super_block *sb, int flags, void *data, int force)
remount_rw = !(flags & MS_RDONLY) && (sb->s_flags & MS_RDONLY);

if (sb->s_op->remount_fs) {
lock_super(sb);
retval = sb->s_op->remount_fs(sb, &flags, data);
unlock_super(sb);
if (retval)
return retval;
}
Expand Down
2 changes: 2 additions & 0 deletions fs/sysv/inode.c
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Original file line number Diff line number Diff line change
Expand Up @@ -61,10 +61,12 @@ static void sysv_write_super(struct super_block *sb)
static int sysv_remount(struct super_block *sb, int *flags, char *data)
{
struct sysv_sb_info *sbi = SYSV_SB(sb);
lock_super(sb);
if (sbi->s_forced_ro)
*flags |= MS_RDONLY;
if (!(*flags & MS_RDONLY))
sb->s_dirt = 1;
unlock_super(sb);
return 0;
}

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11 changes: 10 additions & 1 deletion fs/ufs/super.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1181,6 +1181,7 @@ static int ufs_remount (struct super_block *sb, int *mount_flags, char *data)
unsigned new_mount_opt, ufstype;
unsigned flags;

lock_super(sb);
uspi = UFS_SB(sb)->s_uspi;
flags = UFS_SB(sb)->s_flags;
usb1 = ubh_get_usb_first(uspi);
Expand All @@ -1193,17 +1194,21 @@ static int ufs_remount (struct super_block *sb, int *mount_flags, char *data)
ufstype = UFS_SB(sb)->s_mount_opt & UFS_MOUNT_UFSTYPE;
new_mount_opt = 0;
ufs_set_opt (new_mount_opt, ONERROR_LOCK);
if (!ufs_parse_options (data, &new_mount_opt))
if (!ufs_parse_options (data, &new_mount_opt)) {
unlock_super(sb);
return -EINVAL;
}
if (!(new_mount_opt & UFS_MOUNT_UFSTYPE)) {
new_mount_opt |= ufstype;
} else if ((new_mount_opt & UFS_MOUNT_UFSTYPE) != ufstype) {
printk("ufstype can't be changed during remount\n");
unlock_super(sb);
return -EINVAL;
}

if ((*mount_flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY)) {
UFS_SB(sb)->s_mount_opt = new_mount_opt;
unlock_super(sb);
return 0;
}

Expand All @@ -1228,6 +1233,7 @@ static int ufs_remount (struct super_block *sb, int *mount_flags, char *data)
#ifndef CONFIG_UFS_FS_WRITE
printk("ufs was compiled with read-only support, "
"can't be mounted as read-write\n");
unlock_super(sb);
return -EINVAL;
#else
if (ufstype != UFS_MOUNT_UFSTYPE_SUN &&
Expand All @@ -1236,16 +1242,19 @@ static int ufs_remount (struct super_block *sb, int *mount_flags, char *data)
ufstype != UFS_MOUNT_UFSTYPE_SUNx86 &&
ufstype != UFS_MOUNT_UFSTYPE_UFS2) {
printk("this ufstype is read-only supported\n");
unlock_super(sb);
return -EINVAL;
}
if (!ufs_read_cylinder_structures(sb)) {
printk("failed during remounting\n");
unlock_super(sb);
return -EPERM;
}
sb->s_flags &= ~MS_RDONLY;
#endif
}
UFS_SB(sb)->s_mount_opt = new_mount_opt;
unlock_super(sb);
return 0;
}

Expand Down

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